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Author SHA1 Message Date
Nanyong Sun
dbc6e7d44a nilfs2: fix NULL pointer in nilfs_##name##_attr_release 
In nilfs_##name##_attr_release, kobj->parent should not be referenced
because it is a NULL pointer.  The release() method of kobject is always
called in kobject_put(kobj), in the implementation of kobject_put(), the
kobj->parent will be assigned as NULL before call the release() method.
So just use kobj to get the subgroups, which is more efficient and can fix
a NULL pointer reference problem.

Link: https://lkml.kernel.org/r/20210629022556.3985106-3-sunnanyong@huawei.com
Link: https://lkml.kernel.org/r/1625651306-10829-3-git-send-email-konishi.ryusuke@gmail.com
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:27 -07:00
Nanyong Sun
5f5dec07ac nilfs2: fix memory leak in nilfs_sysfs_create_device_group 
Patch series "nilfs2: fix incorrect usage of kobject".

This patchset from Nanyong Sun fixes memory leak issues and a NULL
pointer dereference issue caused by incorrect usage of kboject in nilfs2
sysfs implementation.

This patch (of 6):

Reported by syzkaller:

  BUG: memory leak
  unreferenced object 0xffff888100ca8988 (size 8):
  comm "syz-executor.1", pid 1930, jiffies 4294745569 (age 18.052s)
  hex dump (first 8 bytes):
  6c 6f 6f 70 31 00 ff ff loop1...
  backtrace:
    kstrdup+0x36/0x70 mm/util.c:60
    kstrdup_const+0x35/0x60 mm/util.c:83
    kvasprintf_const+0xf1/0x180 lib/kasprintf.c:48
    kobject_set_name_vargs+0x56/0x150 lib/kobject.c:289
    kobject_add_varg lib/kobject.c:384 [inline]
    kobject_init_and_add+0xc9/0x150 lib/kobject.c:473
    nilfs_sysfs_create_device_group+0x150/0x7d0 fs/nilfs2/sysfs.c:986
    init_nilfs+0xa21/0xea0 fs/nilfs2/the_nilfs.c:637
    nilfs_fill_super fs/nilfs2/super.c:1046 [inline]
    nilfs_mount+0x7b4/0xe80 fs/nilfs2/super.c:1316
    legacy_get_tree+0x105/0x210 fs/fs_context.c:592
    vfs_get_tree+0x8e/0x2d0 fs/super.c:1498
    do_new_mount fs/namespace.c:2905 [inline]
    path_mount+0xf9b/0x1990 fs/namespace.c:3235
    do_mount+0xea/0x100 fs/namespace.c:3248
    __do_sys_mount fs/namespace.c:3456 [inline]
    __se_sys_mount fs/namespace.c:3433 [inline]
    __x64_sys_mount+0x14b/0x1f0 fs/namespace.c:3433
    do_syscall_x64 arch/x86/entry/common.c:50 [inline]
    do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
    entry_SYSCALL_64_after_hwframe+0x44/0xae

If kobject_init_and_add return with error, then the cleanup of kobject
is needed because memory may be allocated in kobject_init_and_add
without freeing.

And the place of cleanup_dev_kobject should use kobject_put to free the
memory associated with the kobject.  As the section "Kobject removal" of
"Documentation/core-api/kobject.rst" says, kobject_del() just makes the
kobject "invisible", but it is not cleaned up.  And no more cleanup will
do after cleanup_dev_kobject, so kobject_put is needed here.

Link: https://lkml.kernel.org/r/1625651306-10829-1-git-send-email-konishi.ryusuke@gmail.com
Link: https://lkml.kernel.org/r/1625651306-10829-2-git-send-email-konishi.ryusuke@gmail.com
Reported-by: Hulk Robot <hulkci@huawei.com>
Link: https://lkml.kernel.org/r/20210629022556.3985106-2-sunnanyong@huawei.com
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:27 -07:00
Kefeng Wang
8b097881b5 trap: cleanup trap_init() 
There are some empty trap_init() definitions in different ARCHs, Introduce
a new weak trap_init() function to clean them up.

Link: https://lkml.kernel.org/r/20210812123602.76356-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>	[arm32]
Acked-by: Vineet Gupta						[arc]
Acked-by: Michael Ellerman <mpe@ellerman.id.au>			[powerpc]
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Stafford Horne <shorne@gmail.com>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <palmerdabbelt@google.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:27 -07:00
Rasmus Villemoes
b234ed6d62 init: move usermodehelper_enable() to populate_rootfs() 
Currently, usermodehelper is enabled right before PID1 starts going
through the initcalls. However, any call of a usermodehelper from a
pure_, core_, postcore_, arch_, subsys_ or fs_ initcall is futile, as
there is no filesystem contents yet.

Up until commit e7cb072eb9 ("init/initramfs.c: do unpacking
asynchronously"), such calls, whether via some request_module(), a
legacy uevent "/sbin/hotplug" notification or something else, would
just fail silently with (presumably) -ENOENT from
kernel_execve(). However, that commit introduced the
wait_for_initramfs() synchronization hook which must be called from
the usermodehelper exec path right before the kernel_execve, in order
that request_module() et al done from *after* rootfs_initcall()
time (i.e. device_ and late_ initcalls) would continue to find a
populated initramfs as they used to.

Any call of wait_for_initramfs() done before the unpacking has been
scheduled (i.e. before rootfs_initcall time) must just return
immediately [and let the caller find an empty file system] in order
not to deadlock the machine. I mistakenly thought, and my limited
testing confirmed, that there were no such calls, so I added a
pr_warn_once() in wait_for_initramfs(). It turns out that one can
indeed hit request_module() as well as kobject_uevent_env() during
those early init calls, leading to a user-visible warning in the
kernel log emitted consistently for certain configurations.

We could just remove the pr_warn_once(), but I think it's better to
postpone enabling the usermodehelper framework until there is at least
some chance of finding the executable. That is also a little more
efficient in that a lot of work done in umh.c will be elided. However,
it does change the error seen by those early callers from -ENOENT to
-EBUSY, so there is a risk of a regression if any caller care about
the exact error value.

Link: https://lkml.kernel.org/r/20210728134638.329060-1-linux@rasmusvillemoes.dk
Fixes: e7cb072eb9 ("init/initramfs.c: do unpacking asynchronously")
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reported-by: Alexander Egorenkov <egorenar@linux.ibm.com>
Reported-by: Bruno Goncalves <bgoncalv@redhat.com>
Reported-by: Heiner Kallweit <hkallweit1@gmail.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:27 -07:00
Nicholas Piggin
1e1c15839d fs/epoll: use a per-cpu counter for user's watches count 
This counter tracks the number of watches a user has, to compare against
the 'max_user_watches' limit. This causes a scalability bottleneck on
SPECjbb2015 on large systems as there is only one user. Changing to a
per-cpu counter increases throughput of the benchmark by about 30% on a
16-socket, > 1000 thread system.

[rdunlap@infradead.org: fix build errors in kernel/user.c when CONFIG_EPOLL=n]
[npiggin@gmail.com: move ifdefs into wrapper functions, slightly improve panic message]
  Link: https://lkml.kernel.org/r/1628051945.fens3r99ox.astroid@bobo.none
[akpm@linux-foundation.org: tweak user_epoll_alloc(), per Guenter]
  Link: https://lkml.kernel.org/r/20210804191421.GA1900577@roeck-us.net

Link: https://lkml.kernel.org/r/20210802032013.2751916-1-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reported-by: Anton Blanchard <anton@ozlabs.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:27 -07:00
Joe Perches
4ce9f97045 checkpatch: improve GIT_COMMIT_ID test 
The preferred git commit id reference has the form

	commit <SHA-1> ("Title line")

where SHA-1 is the commit hex hash with a minimum lenth of 12 and ("Title
line") is the complete title line of the commit with a (" prefix and ")
suffix.

The current tests fail when the "Title line" has one or more embedded
double quotes.

Improve the test that finds the commit SHA-1 hex hash then ("Title line")
by using $balanced_parens for a maximum of 3 consecutive lines.

[akpm@linux-foundation.org: add missing &&]

Link: https://lkml.kernel.org/r/976c6cdd680db4b55ae31b5fc2d1779da5c0dc66.camel@perches.com
Signed-off-by: Joe Perches <joe@perches.com>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Denis Efremov <efremov@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:27 -07:00
Mimi Zohar
046fc741e3 checkpatch: make email address check case insensitive 
Instead of checkpatch requiring the patch author to exactly match the
signed-off-by tag, commit 48ca2d8ac8 ("checkpatch: add new warnings to
author signoff checks.") safely relaxed this requirement.

Although the local-part of an email address (local-part@domain), may be
case sensitive, exploiting the case sensitivity of mailbox local-parts
impedes interoperability and is discouraged.  Mailbox domains follow
normal DNS rules and are hence not case sensitive.  (Refer to
https://datatracker.ietf.org/doc/html/rfc5321#section-2.4.)

Further relax the patch author and signed-off-by tag comparison by making
the email address check case insensitive.

Link: https://lkml.kernel.org/r/20210816112725.173206-1-zohar@linux.ibm.com
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
Acked-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:27 -07:00
Joe Perches
d2af5aa6c0 checkpatch: support wide strings 
Allow prefixing typical strings with L for wide strings and u for unicode
strings.

Link: https://lkml.kernel.org/r/20210801170733.1.I3f9784fd3c1007d08ec2e70b151d137687575495@changeid
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Cc: Dwaipayan Ray <dwaipayanray1@gmail.com>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:27 -07:00
Andy Shevchenko
7fc5b57132 tools: rename bitmap_alloc() to bitmap_zalloc() 
Rename bitmap_alloc() to bitmap_zalloc() in tools to follow the bitmap API
in the kernel.

No functional changes intended.

Link: https://lkml.kernel.org/r/20210814211713.180533-14-yury.norov@gmail.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Suggested-by: Yury Norov <yury.norov@gmail.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Lobakin <alobakin@pm.me>
Cc: Alexey Klimov <aklimov@redhat.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:27 -07:00
Randy Dunlap
44e5599775 lib/iov_iter.c: fix kernel-doc warnings 
Fix all kernel-doc warnings in lib/iov_iter.c:

lib/iov_iter.c:695: warning: Function parameter or member 'i' not described in '_copy_mc_to_iter'
lib/iov_iter.c:695: warning: Excess function parameter 'iter' description in '_copy_mc_to_iter'
lib/iov_iter.c:695: warning: No description found for return value of '_copy_mc_to_iter'
lib/iov_iter.c:758: warning: Function parameter or member 'i' not described in '_copy_from_iter_flushcache'
lib/iov_iter.c:758: warning: Excess function parameter 'iter' description in '_copy_from_iter_flushcache'
lib/iov_iter.c:758: warning: No description found for return value of '_copy_from_iter_flushcache'

Link: https://lkml.kernel.org/r/20210809051053.6531-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Randy Dunlap
83a29beb23 lib/dump_stack: correct kernel-doc notation 
Fix kernel-doc warnings in dump_stack.c:

lib/dump_stack.c:97: warning: Function parameter or member 'log_lvl' not described in 'dump_stack_lvl'
lib/dump_stack.c:97: warning: expecting prototype for dump_stack(). Prototype was for dump_stack_lvl() instead

Link: https://lkml.kernel.org/r/20210809051643.17567-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Daniel Latypov
36f33b5629 lib/test: convert test_sort.c to use KUnit 
This follows up commit ebd09577be ("lib/test: convert
lib/test_list_sort.c to use KUnit").

Converting this test to KUnit makes the test a bit shorter, standardizes
how it reports pass/fail, and adds an easier way to run the test [1].

Like ebd09577be, this leaves the file and Kconfig option name the same,
but slightly changes their dependencies (needs CONFIG_KUNIT).

[1] Can be run via
$ ./tools/testing/kunit/kunit.py run --kunitconfig /dev/stdin <<EOF
CONFIG_KUNIT=y
CONFIG_TEST_SORT=y
EOF

[11:30:27] Starting KUnit Kernel ...
[11:30:30] ============================================================
[11:30:30] ======== [PASSED] lib_sort ========
[11:30:30] [PASSED] test_sort
[11:30:30] ============================================================
[11:30:30] Testing complete. 1 tests run. 0 failed. 0 crashed. 0 skipped.
[11:30:30] Elapsed time: 37.032s total, 0.001s configuring, 34.090s building, 0.000s running

Note: this is the time it took after a `make mrproper`.

With an incremental rebuild, this looks more like:
[11:38:58] Elapsed time: 6.444s total, 0.001s configuring, 3.416s building, 0.000s running

Since the test has no dependencies, it can also be run (with some other
tests) with just:
$ ./tools/testing/kunit/kunit.py run

Link: https://lkml.kernel.org/r/20210715232441.1380885-1-dlatypov@google.com
Signed-off-by: Daniel Latypov <dlatypov@google.com>
Cc: Pravin Shedge <pravin.shedge4linux@gmail.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Geert Uytterhoeven
8ba739ede4 math: RATIONAL_KUNIT_TEST should depend on RATIONAL instead of selecting it 
RATIONAL_KUNIT_TEST selects RATIONAL, thus enabling an optional feature
the user may not want to have enabled.  Fix this by making the test depend
on RATIONAL instead.

Link: https://lkml.kernel.org/r/20210706100945.3803694-3-geert@linux-m68k.org
Fixes: b6c75c4afc ("lib/math/rational: add Kunit test cases")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Trent Piepho <tpiepho@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Geert Uytterhoeven
bcda5fd344 math: make RATIONAL tristate 
Patch series "math: RATIONAL and RATIONAL_KUNIT_TEST improvements".

This series makes the RATIONAL symbol tristate, so it is not forced
builtin if all users are modular, and makes the RATIONAL_KUNIT_TEST depend
on RATIONAL, to avoid enabling RATIONAL if there are no real users.

This patch (of 2):

All but one symbols that select RATIONAL are tristate, but RATIONAL itself
is bool.  Change it to tristate, so the rational fractions support code
can be modular if no builtin code relies on it.

Link: https://lkml.kernel.org/r/20210706100945.3803694-1-geert@linux-m68k.org
Link: https://lkml.kernel.org/r/20210706100945.3803694-2-geert@linux-m68k.org
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Trent Piepho <tpiepho@gmail.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Nathan Chancellor
1c3493bb29 Documentation/llvm: update IRC location 
This should have been done with commit 91ed3ed0f7 ("MAINTAINERS: update
ClangBuiltLinux IRC chat") but I did not realize it was in two separate
spots.

Link: https://lkml.kernel.org/r/20210825211823.6406-3-nathan@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Nathan Chancellor
28f8fc19b2 Documentation/llvm: update mailing list 
We are now at llvm@lists.linux.dev.

Link: https://lkml.kernel.org/r/20210825211823.6406-2-nathan@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Nathan Chancellor
726248b62f MAINTAINERS: update ClangBuiltLinux mailing list 
We are now at llvm@lists.linux.dev.

Link: https://lkml.kernel.org/r/20210825211823.6406-1-nathan@kernel.org
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Pavel Skripkin
2d186afd04 profiling: fix shift-out-of-bounds bugs 
Syzbot reported shift-out-of-bounds bug in profile_init().
The problem was in incorrect prof_shift. Since prof_shift value comes from
userspace we need to clamp this value into [0, BITS_PER_LONG -1]
boundaries.

Second possible shiht-out-of-bounds was found by Tetsuo:
sample_step local variable in read_profile() had "unsigned int" type,
but prof_shift allows to make a BITS_PER_LONG shift. So, to prevent
possible shiht-out-of-bounds sample_step type was changed to
"unsigned long".

Also, "unsigned short int" will be sufficient for storing
[0, BITS_PER_LONG] value, that's why there is no need for
"unsigned long" prof_shift.

Link: https://lkml.kernel.org/r/20210813140022.5011-1-paskripkin@gmail.com
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-and-tested-by: syzbot+e68c89a9510c159d9684@syzkaller.appspotmail.com
Suggested-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Pavel Skripkin <paskripkin@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Yang Yang
3c91dda97e kernel/acct.c: use dedicated helper to access rlimit values 
Use rlimit() helper instead of manually writing whole chain from
task to rlimit value. See patch "posix-cpu-timers: Use dedicated
helper to access rlimit values".

Link: https://lkml.kernel.org/r/20210728030822.524789-1-yang.yang29@zte.com.cn
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Reported-by: Zeal Robot <zealci@zte.com.cn>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: sh_def@163.com <sh_def@163.com>
Cc: Yang Yang <yang.yang29@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Daniel Lezcano
18821693b9 phy/drivers/stm32: use HZ macros 
HZ unit conversion macros are available in units.h, use them and remove
the duplicate definition.

Link: https://lkml.kernel.org/r/20210816114732.1834145-11-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Christian Eggers <ceggers@arri.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Daniel Lezcano
9ef347c3df mtd/drivers/nand: use HZ macros 
HZ unit conversion macros are available in units.h, use them and remove
the duplicate definition.

Link: https://lkml.kernel.org/r/20210816114732.1834145-10-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Christian Eggers <ceggers@arri.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Daniel Lezcano
09704a941c i2c/drivers/ov02q10: use HZ macros 
HZ unit conversion macros are available in units.h, use them and remove
the duplicate definition.

Link: https://lkml.kernel.org/r/20210816114732.1834145-9-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Christian Eggers <ceggers@arri.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Daniel Lezcano
87000e7fe0 iio/drivers/hid-sensor: use HZ macros 
HZ unit conversion macros are available in units.h, use them and remove
the duplicate definition.

Link: https://lkml.kernel.org/r/20210816114732.1834145-8-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Christian Eggers <ceggers@arri.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Daniel Lezcano
d59eacaac9 hwmon/drivers/mr75203: use HZ macros 
HZ unit conversion macros are available in units.h, use them and remove
the duplicate definition.

The new macro is an unsigned long.  The code dealing with it is
considering as an unsigned long also.

Link: https://lkml.kernel.org/r/20210816114732.1834145-7-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Christian Eggers <ceggers@arri.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Daniel Lezcano
55c653e0be iio/drivers/as73211: use HZ macros 
HZ unit conversion macros are available in units.h, use them and remove
the duplicate definition.

Link: https://lkml.kernel.org/r/20210816114732.1834145-6-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Christian Eggers <ceggers@arri.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Daniel Lezcano
04c8984ae3 devfreq: use HZ macros 
HZ unit conversion macros are available in units.h, use them and remove
the duplicate definition.

The new macro has an unsigned long type.

All the code is dealing with unsigned long and the code using the macro is
doing a coercitive cast to unsigned long.

Link: https://lkml.kernel.org/r/20210816114732.1834145-5-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Christian Eggers <ceggers@arri.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:26 -07:00
Daniel Lezcano
73b718c617 thermal/drivers/devfreq_cooling: use HZ macros 
HZ unit conversion macros are available in units.h, use them and remove
the duplicate definition.

The new macro uses a unsigned long type which is already the type in the
current code via the 'freq' variable.

Link: https://lkml.kernel.org/r/20210816114732.1834145-4-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Christian Eggers <ceggers@arri.de>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
Daniel Lezcano
e2c77032fc units: add the HZ macros 
The macros for the unit conversion for frequency are duplicated in
different places.

Provide these macros in the 'units' header, so they can be reused.

Link: https://lkml.kernel.org/r/20210816114732.1834145-3-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Christian Eggers <ceggers@arri.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
Daniel Lezcano
c9221919a2 units: change from 'L' to 'UL' 
Patch series "Add Hz macros", v3.

There are multiple definitions of the HZ_PER_MHZ or HZ_PER_KHZ in the
different drivers.  Instead of duplicating this definition again and
again, add one in the units.h header to be reused in all the place the
redefiniton occurs.

At the same time, change the type of the Watts, as they can not be
negative.

This patch (of 10):

The users of the macros are safe to be assigned with an unsigned instead
of signed as the variables using them are themselves unsigned.

Link: https://lkml.kernel.org/r/20210816114732.1834145-1-daniel.lezcano@linaro.org
Link: https://lkml.kernel.org/r/20210816114732.1834145-2-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Christian Eggers <ceggers@arri.de>
Cc: Lukasz Luba <lukasz.luba@arm.com>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Chanwoo Choi <cw00.choi@samsung.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
Andy Shevchenko
a8a47cf5ce include/linux/once.h: fix trivia typo Not -> Note 
Fix trivia typo Not -> Note in the comment to DO_ONCE().

Link: https://lkml.kernel.org/r/20210722184349.76290-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
Colin Ian King
c226bc3cd9 arch: Kconfig: fix spelling mistake "seperate" -> "separate" 
Threre is a spelling mistake in the Kconfig text. Fix it.

Link: https://lkml.kernel.org/r/20210704095207.37342-1-colin.king@canonical.com
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
Ohhoon Kwon
c2f273ebd8 connector: send event on write to /proc/[pid]/comm 
While comm change event via prctl has been reported to proc connector by
'commit f786ecba41 ("connector: add comm change event report to proc
connector")', connector listeners were missing comm changes by explicit
writes on /proc/[pid]/comm.

Let explicit writes on /proc/[pid]/comm report to proc connector.

Link: https://lkml.kernel.org/r/20210701133458epcms1p68e9eb9bd0eee8903ba26679a37d9d960@epcms1p6
Signed-off-by: Ohhoon Kwon <ohoono.kwon@samsung.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
Christoph Hellwig
8d23b2080b proc: stop using seq_get_buf in proc_task_name 
Use seq_escape_str and seq_printf instead of poking holes into the
seq_file abstraction.

Link: https://lkml.kernel.org/r/20210810151945.1795567-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
Greg Kroah-Hartman
3843c50a78 percpu: remove export of pcpu_base_addr 
This is not needed by any modules, so remove the export.

Link: https://lkml.kernel.org/r/20210722185814.504541-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
Randy Dunlap
0a9d991c42 alpha: pci-sysfs: fix all kernel-doc warnings 
Fix all kernel-doc warnings in arch/alpha/kernel/pci-sysfs.c:

  arch/alpha/kernel/pci-sysfs.c:67: warning: No description found for return value of 'pci_mmap_resource'
  arch/alpha/kernel/pci-sysfs.c:115: warning: Function parameter or member 'pdev' not described in 'pci_remove_resource_files'
  arch/alpha/kernel/pci-sysfs.c:115: warning: Excess function parameter 'dev' description in 'pci_remove_resource_files'
  arch/alpha/kernel/pci-sysfs.c:230: warning: Function parameter or member 'pdev' not described in 'pci_create_resource_files'
  arch/alpha/kernel/pci-sysfs.c:230: warning: Excess function parameter 'dev' description in 'pci_create_resource_files'
  arch/alpha/kernel/pci-sysfs.c:232: warning: No description found for return value of 'pci_create_resource_files'
  arch/alpha/kernel/pci-sysfs.c:305: warning: Function parameter or member 'bus' not described in 'pci_adjust_legacy_attr'
  arch/alpha/kernel/pci-sysfs.c:305: warning: Excess function parameter 'b' description in 'pci_adjust_legacy_attr'

Link: https://lkml.kernel.org/r/20210808185249.31442-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
Randy Dunlap
5ecae8f6aa alpha: agp: make empty macros use do-while-0 style 
Copy these macros from ia64/include/asm/agp.h to avoid the
"empty-body" in 'if' statment warning.

drivers/char/agp/generic.c: In function 'agp_generic_destroy_page':
../drivers/char/agp/generic.c:1265:42: warning: suggest braces around empty body in an 'if' statement [-Wempty-body]
 1265 |                 unmap_page_from_agp(page);

Link: https://lkml.kernel.org/r/20210809030822.20658-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: David Airlie <airlied@linux.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
SeongJae Park
75e39b1a36 MAINTAINERS: update for DAMON 
This commit updates MAINTAINERS file for DAMON related files.

Link: https://lkml.kernel.org/r/20210716081449.22187-14-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Markus Boehme <markubo@amazon.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Fernand Sieber <sieberf@amazon.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
SeongJae Park
b348eb7abd mm/damon: add user space selftests 
This commit adds a simple user space tests for DAMON.  The tests are using
kselftest framework.

Link: https://lkml.kernel.org/r/20210716081449.22187-13-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Markus Boehme <markubo@amazon.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Fernand Sieber <sieberf@amazon.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
SeongJae Park
17ccae8bb5 mm/damon: add kunit tests 
This commit adds kunit based unit tests for the core and the virtual
address spaces monitoring primitives of DAMON.

Link: https://lkml.kernel.org/r/20210716081449.22187-12-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Brendan Higgins <brendanhiggins@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Fernand Sieber <sieberf@amazon.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
SeongJae Park
c4ba6014ae Documentation: add documents for DAMON 
This commit adds documents for DAMON under
`Documentation/admin-guide/mm/damon/` and `Documentation/vm/damon/`.

Link: https://lkml.kernel.org/r/20210716081449.22187-11-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Reviewed-by: Markus Boehme <markubo@amazon.de>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
SeongJae Park
75c1c2b53c mm/damon/dbgfs: support multiple contexts 
In some use cases, users would want to run multiple monitoring context.
For example, if a user wants a high precision monitoring and dedicating
multiple CPUs for the job is ok, because DAMON creates one monitoring
thread per one context, the user can split the monitoring target regions
into multiple small regions and create one context for each region.  Or,
someone might want to simultaneously monitor different address spaces,
e.g., both virtual address space and physical address space.

The DAMON's API allows such usage, but 'damon-dbgfs' does not.  Therefore,
only kernel space DAMON users can do multiple contexts monitoring.

This commit allows the user space DAMON users to use multiple contexts
monitoring by introducing two new 'damon-dbgfs' debugfs files,
'mk_context' and 'rm_context'.  Users can create a new monitoring context
by writing the desired name of the new context to 'mk_context'.  Then, a
new directory with the name and having the files for setting of the
context ('attrs', 'target_ids' and 'record') will be created under the
debugfs directory.  Writing the name of the context to remove to
'rm_context' will remove the related context and directory.

Link: https://lkml.kernel.org/r/20210716081449.22187-10-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
SeongJae Park
429538e854 mm/damon/dbgfs: export kdamond pid to the user space 
For CPU usage accounting, knowing pid of the monitoring thread could be
helpful.  For example, users could use cpuaccount cgroups with the pid.

This commit therefore exports the pid of currently running monitoring
thread to the user space via 'kdamond_pid' file in the debugfs directory.

Link: https://lkml.kernel.org/r/20210716081449.22187-9-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:25 -07:00
SeongJae Park
4bc05954d0 mm/damon: implement a debugfs-based user space interface 
DAMON is designed to be used by kernel space code such as the memory
management subsystems, and therefore it provides only kernel space API.
That said, letting the user space control DAMON could provide some
benefits to them.  For example, it will allow user space to analyze their
specific workloads and make their own special optimizations.

For such cases, this commit implements a simple DAMON application kernel
module, namely 'damon-dbgfs', which merely wraps the DAMON api and exports
those to the user space via the debugfs.

'damon-dbgfs' exports three files, ``attrs``, ``target_ids``, and
``monitor_on`` under its debugfs directory, ``<debugfs>/damon/``.

Attributes
----------

Users can read and write the ``sampling interval``, ``aggregation
interval``, ``regions update interval``, and min/max number of monitoring
target regions by reading from and writing to the ``attrs`` file.  For
example, below commands set those values to 5 ms, 100 ms, 1,000 ms, 10,
1000 and check it again::

    # cd <debugfs>/damon
    # echo 5000 100000 1000000 10 1000 > attrs
    # cat attrs
    5000 100000 1000000 10 1000

Target IDs
----------

Some types of address spaces supports multiple monitoring target.  For
example, the virtual memory address spaces monitoring can have multiple
processes as the monitoring targets.  Users can set the targets by writing
relevant id values of the targets to, and get the ids of the current
targets by reading from the ``target_ids`` file.  In case of the virtual
address spaces monitoring, the values should be pids of the monitoring
target processes.  For example, below commands set processes having pids
42 and 4242 as the monitoring targets and check it again::

    # cd <debugfs>/damon
    # echo 42 4242 > target_ids
    # cat target_ids
    42 4242

Note that setting the target ids doesn't start the monitoring.

Turning On/Off
--------------

Setting the files as described above doesn't incur effect unless you
explicitly start the monitoring.  You can start, stop, and check the
current status of the monitoring by writing to and reading from the
``monitor_on`` file.  Writing ``on`` to the file starts the monitoring of
the targets with the attributes.  Writing ``off`` to the file stops those.
DAMON also stops if every targets are invalidated (in case of the virtual
memory monitoring, target processes are invalidated when terminated).
Below example commands turn on, off, and check the status of DAMON::

    # cd <debugfs>/damon
    # echo on > monitor_on
    # echo off > monitor_on
    # cat monitor_on
    off

Please note that you cannot write to the above-mentioned debugfs files
while the monitoring is turned on.  If you write to the files while DAMON
is running, an error code such as ``-EBUSY`` will be returned.

[akpm@linux-foundation.org: remove unneeded "alloc failed" printks]
[akpm@linux-foundation.org: replace macro with static inline]

Link: https://lkml.kernel.org/r/20210716081449.22187-8-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:24 -07:00
SeongJae Park
2fcb93629a mm/damon: add a tracepoint 
This commit adds a tracepoint for DAMON.  It traces the monitoring results
of each region for each aggregation interval.  Using this, DAMON can
easily integrated with tracepoints supporting tools such as perf.

Link: https://lkml.kernel.org/r/20210716081449.22187-7-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:24 -07:00
SeongJae Park
3f49584b26 mm/damon: implement primitives for the virtual memory address spaces 
This commit introduces a reference implementation of the address space
specific low level primitives for the virtual address space, so that users
of DAMON can easily monitor the data accesses on virtual address spaces of
specific processes by simply configuring the implementation to be used by
DAMON.

The low level primitives for the fundamental access monitoring are defined
in two parts:

1. Identification of the monitoring target address range for the address
   space.
2. Access check of specific address range in the target space.

The reference implementation for the virtual address space does the works
as below.

PTE Accessed-bit Based Access Check
-----------------------------------

The implementation uses PTE Accessed-bit for basic access checks.  That
is, it clears the bit for the next sampling target page and checks whether
it is set again after one sampling period.  This could disturb the reclaim
logic.  DAMON uses ``PG_idle`` and ``PG_young`` page flags to solve the
conflict, as Idle page tracking does.

VMA-based Target Address Range Construction
-------------------------------------------

Only small parts in the super-huge virtual address space of the processes
are mapped to physical memory and accessed.  Thus, tracking the unmapped
address regions is just wasteful.  However, because DAMON can deal with
some level of noise using the adaptive regions adjustment mechanism,
tracking every mapping is not strictly required but could even incur a
high overhead in some cases.  That said, too huge unmapped areas inside
the monitoring target should be removed to not take the time for the
adaptive mechanism.

For the reason, this implementation converts the complex mappings to three
distinct regions that cover every mapped area of the address space.  Also,
the two gaps between the three regions are the two biggest unmapped areas
in the given address space.  The two biggest unmapped areas would be the
gap between the heap and the uppermost mmap()-ed region, and the gap
between the lowermost mmap()-ed region and the stack in most of the cases.
Because these gaps are exceptionally huge in usual address spaces,
excluding these will be sufficient to make a reasonable trade-off.  Below
shows this in detail::

    <heap>
    <BIG UNMAPPED REGION 1>
    <uppermost mmap()-ed region>
    (small mmap()-ed regions and munmap()-ed regions)
    <lowermost mmap()-ed region>
    <BIG UNMAPPED REGION 2>
    <stack>

[akpm@linux-foundation.org: mm/damon/vaddr.c needs highmem.h for kunmap_atomic()]
[sjpark@amazon.de: remove unnecessary PAGE_EXTENSION setup]
  Link: https://lkml.kernel.org/r/20210806095153.6444-2-sj38.park@gmail.com
[sjpark@amazon.de: safely walk page table]
  Link: https://lkml.kernel.org/r/20210831161800.29419-1-sj38.park@gmail.com

Link: https://lkml.kernel.org/r/20210716081449.22187-6-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:24 -07:00
SeongJae Park
1c676e0d9b mm/idle_page_tracking: make PG_idle reusable 
PG_idle and PG_young allow the two PTE Accessed bit users, Idle Page
Tracking and the reclaim logic concurrently work while not interfering
with each other.  That is, when they need to clear the Accessed bit, they
set PG_young to represent the previous state of the bit, respectively.
And when they need to read the bit, if the bit is cleared, they further
read the PG_young to know whether the other has cleared the bit meanwhile
or not.

For yet another user of the PTE Accessed bit, we could add another page
flag, or extend the mechanism to use the flags.  For the DAMON usecase,
however, we don't need to do that just yet.  IDLE_PAGE_TRACKING and DAMON
are mutually exclusive, so there's only ever going to be one user of the
current set of flags.

In this commit, we split out the CONFIG options to allow for the use of
PG_young and PG_idle outside of idle page tracking.

In the next commit, DAMON's reference implementation of the virtual memory
address space monitoring primitives will use it.

[sjpark@amazon.de: set PAGE_EXTENSION for non-64BIT]
  Link: https://lkml.kernel.org/r/20210806095153.6444-1-sj38.park@gmail.com
[akpm@linux-foundation.org: tweak Kconfig text]
[sjpark@amazon.de: hide PAGE_IDLE_FLAG from users]
  Link: https://lkml.kernel.org/r/20210813081238.34705-1-sj38.park@gmail.com

Link: https://lkml.kernel.org/r/20210716081449.22187-5-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Leonard Foerster <foersleo@amazon.de>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:24 -07:00
SeongJae Park
b9a6ac4e4e mm/damon: adaptively adjust regions 
Even somehow the initial monitoring target regions are well constructed to
fulfill the assumption (pages in same region have similar access
frequencies), the data access pattern can be dynamically changed.  This
will result in low monitoring quality.  To keep the assumption as much as
possible, DAMON adaptively merges and splits each region based on their
access frequency.

For each ``aggregation interval``, it compares the access frequencies of
adjacent regions and merges those if the frequency difference is small.
Then, after it reports and clears the aggregated access frequency of each
region, it splits each region into two or three regions if the total
number of regions will not exceed the user-specified maximum number of
regions after the split.

In this way, DAMON provides its best-effort quality and minimal overhead
while keeping the upper-bound overhead that users set.

Link: https://lkml.kernel.org/r/20210716081449.22187-4-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:24 -07:00
SeongJae Park
f23b8eee18 mm/damon/core: implement region-based sampling 
To avoid the unbounded increase of the overhead, DAMON groups adjacent
pages that are assumed to have the same access frequencies into a
region.  As long as the assumption (pages in a region have the same
access frequencies) is kept, only one page in the region is required to
be checked.  Thus, for each ``sampling interval``,

 1. the 'prepare_access_checks' primitive picks one page in each region,
 2. waits for one ``sampling interval``,
 3. checks whether the page is accessed meanwhile, and
 4. increases the access count of the region if so.

Therefore, the monitoring overhead is controllable by adjusting the
number of regions.  DAMON allows both the underlying primitives and user
callbacks to adjust regions for the trade-off.  In other words, this
commit makes DAMON to use not only time-based sampling but also
space-based sampling.

This scheme, however, cannot preserve the quality of the output if the
assumption is not guaranteed.  Next commit will address this problem.

Link: https://lkml.kernel.org/r/20210716081449.22187-3-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Marco Elver <elver@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:24 -07:00
SeongJae Park
2224d84854 mm: introduce Data Access MONitor (DAMON) 
Patch series "Introduce Data Access MONitor (DAMON)", v34.

Introduction
============

DAMON is a data access monitoring framework for the Linux kernel.  The
core mechanisms of DAMON called 'region based sampling' and 'adaptive
regions adjustment' (refer to 'mechanisms.rst' in the 11th patch of this
patchset for the detail) make it

- accurate (The monitored information is useful for DRAM level memory
  management.  It might not appropriate for Cache-level accuracy,
  though.),

- light-weight (The monitoring overhead is low enough to be applied
  online while making no impact on the performance of the target
  workloads.), and

- scalable (the upper-bound of the instrumentation overhead is
  controllable regardless of the size of target workloads.).

Using this framework, therefore, several memory management mechanisms such
as reclamation and THP can be optimized to aware real data access
patterns.  Experimental access pattern aware memory management
optimization works that incurring high instrumentation overhead will be
able to have another try.

Though DAMON is for kernel subsystems, it can be easily exposed to the
user space by writing a DAMON-wrapper kernel subsystem.  Then, user space
users who have some special workloads will be able to write personalized
tools or applications for deeper understanding and specialized
optimizations of their systems.

DAMON is also merged in two public Amazon Linux kernel trees that based on
v5.4.y[1] and v5.10.y[2].

[1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon
[2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon

The userspace tool[1] is available, released under GPLv2, and actively
being maintained.  I am also planning to implement another basic user
interface in perf[2].  Also, the basic test suite for DAMON is available
under GPLv2[3].

[1] https://github.com/awslabs/damo
[2] https://lore.kernel.org/linux-mm/20210107120729.22328-1-sjpark@amazon.com/
[3] https://github.com/awslabs/damon-tests

Long-term Plan
--------------

DAMON is a part of a project called Data Access-aware Operating System
(DAOS).  As the name implies, I want to improve the performance and
efficiency of systems using fine-grained data access patterns.  The
optimizations are for both kernel and user spaces.  I will therefore
modify or create kernel subsystems, export some of those to user space and
implement user space library / tools.  Below shows the layers and
components for the project.

    ---------------------------------------------------------------------------
    Primitives:     PTE Accessed bit, PG_idle, rmap, (Intel CMT), ...
    Framework:      DAMON
    Features:       DAMOS, virtual addr, physical addr, ...
    Applications:   DAMON-debugfs, (DARC), ...
    ^^^^^^^^^^^^^^^^^^^^^^^    KERNEL SPACE    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

    Raw Interface:  debugfs, (sysfs), (damonfs), tracepoints, (sys_damon), ...

    vvvvvvvvvvvvvvvvvvvvvvv    USER SPACE      vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    Library:        (libdamon), ...
    Tools:          DAMO, (perf), ...
    ---------------------------------------------------------------------------

The components in parentheses or marked as '...' are not implemented yet
but in the future plan.  IOW, those are the TODO tasks of DAOS project.
For more detail, please refer to the plans:
https://lore.kernel.org/linux-mm/20201202082731.24828-1-sjpark@amazon.com/

Evaluations
===========

We evaluated DAMON's overhead, monitoring quality and usefulness using 24
realistic workloads on my QEMU/KVM based virtual machine running a kernel
that v24 DAMON patchset is applied.

DAMON is lightweight.  It increases system memory usage by 0.39% and slows
target workloads down by 1.16%.

DAMON is accurate and useful for memory management optimizations.  An
experimental DAMON-based operation scheme for THP, namely 'ethp', removes
76.15% of THP memory overheads while preserving 51.25% of THP speedup.
Another experimental DAMON-based 'proactive reclamation' implementation,
'prcl', reduces 93.38% of residential sets and 23.63% of system memory
footprint while incurring only 1.22% runtime overhead in the best case
(parsec3/freqmine).

NOTE that the experimental THP optimization and proactive reclamation are
not for production but only for proof of concepts.

Please refer to the official document[1] or "Documentation/admin-guide/mm:
Add a document for DAMON" patch in this patchset for detailed evaluation
setup and results.

[1] https://damonitor.github.io/doc/html/latest-damon/admin-guide/mm/damon/eval.html

Real-world User Story
=====================

In summary, DAMON has used on production systems and proved its usefulness.

DAMON as a profiler
-------------------

We analyzed characteristics of a large scale production systems of our
customers using DAMON.  The systems utilize 70GB DRAM and 36 CPUs.  From
this, we were able to find interesting things below.

There were obviously different access pattern under idle workload and
active workload.  Under the idle workload, it accessed large memory
regions with low frequency, while the active workload accessed small
memory regions with high freuqnecy.

DAMON found a 7GB memory region that showing obviously high access
frequency under the active workload.  We believe this is the
performance-effective working set and need to be protected.

There was a 4KB memory region that showing highest access frequency under
not only active but also idle workloads.  We think this must be a hottest
code section like thing that should never be paged out.

For this analysis, DAMON used only 0.3-1% of single CPU time.  Because we
used recording-based analysis, it consumed about 3-12 MB of disk space per
20 minutes.  This is only small amount of disk space, but we can further
reduce the disk usage by using non-recording-based DAMON features.  I'd
like to argue that only DAMON can do such detailed analysis (finding 4KB
highest region in 70GB memory) with the light overhead.

DAMON as a system optimization tool
-----------------------------------

We also found below potential performance problems on the systems and made
DAMON-based solutions.

The system doesn't want to make the workload suffer from the page
reclamation and thus it utilizes enough DRAM but no swap device.  However,
we found the system is actively reclaiming file-backed pages, because the
system has intensive file IO.  The file IO turned out to be not
performance critical for the workload, but the customer wanted to ensure
performance critical file-backed pages like code section to not mistakenly
be evicted.

Using direct IO should or `mlock()` would be a straightforward solution,
but modifying the user space code is not easy for the customer.
Alternatively, we could use DAMON-based operation scheme[1].  By using it,
we can ask DAMON to track access frequency of each region and make
'process_madvise(MADV_WILLNEED)[2]' call for regions having specific size
and access frequency for a time interval.

We also found the system is having high number of TLB misses.  We tried
'always' THP enabled policy and it greatly reduced TLB misses, but the
page reclamation also been more frequent due to the THP internal
fragmentation caused memory bloat.  We could try another DAMON-based
operation scheme that applies 'MADV_HUGEPAGE' to memory regions having
>=2MB size and high access frequency, while applying 'MADV_NOHUGEPAGE' to
regions having <2MB size and low access frequency.

We do not own the systems so we only reported the analysis results and
possible optimization solutions to the customers.  The customers satisfied
about the analysis results and promised to try the optimization guides.

[1] https://lore.kernel.org/linux-mm/20201006123931.5847-1-sjpark@amazon.com/
[2] https://lore.kernel.org/linux-api/20200622192900.22757-4-minchan@kernel.org/

Comparison with Idle Page Tracking
==================================

Idle Page Tracking allows users to set and read idleness of pages using a
bitmap file which represents each page with each bit of the file.  One
recommended usage of it is working set size detection.  Users can do that
by

    1. find PFN of each page for workloads in interest,
    2. set all the pages as idle by doing writes to the bitmap file,
    3. wait until the workload accesses its working set, and
    4. read the idleness of the pages again and count pages became not idle.

NOTE: While Idle Page Tracking is for user space users, DAMON is primarily
designed for kernel subsystems though it can easily exposed to the user
space.  Hence, this section only assumes such user space use of DAMON.

For what use cases Idle Page Tracking would be better?
------------------------------------------------------

1. Flexible usecases other than hotness monitoring.

Because Idle Page Tracking allows users to control the primitive (Page
idleness) by themselves, Idle Page Tracking users can do anything they
want.  Meanwhile, DAMON is primarily designed to monitor the hotness of
each memory region.  For this, DAMON asks users to provide sampling
interval and aggregation interval.  For the reason, there could be some
use case that using Idle Page Tracking is simpler.

2. Physical memory monitoring.

Idle Page Tracking receives PFN range as input, so natively supports
physical memory monitoring.

DAMON is designed to be extensible for multiple address spaces and use
cases by implementing and using primitives for the given use case.
Therefore, by theory, DAMON has no limitation in the type of target
address space as long as primitives for the given address space exists.
However, the default primitives introduced by this patchset supports only
virtual address spaces.

Therefore, for physical memory monitoring, you should implement your own
primitives and use it, or simply use Idle Page Tracking.

Nonetheless, RFC patchsets[1] for the physical memory address space
primitives is already available.  It also supports user memory same to
Idle Page Tracking.

[1] https://lore.kernel.org/linux-mm/20200831104730.28970-1-sjpark@amazon.com/

For what use cases DAMON is better?
-----------------------------------

1. Hotness Monitoring.

Idle Page Tracking let users know only if a page frame is accessed or not.
For hotness check, the user should write more code and use more memory.
DAMON do that by itself.

2. Low Monitoring Overhead

DAMON receives user's monitoring request with one step and then provide
the results.  So, roughly speaking, DAMON require only O(1) user/kernel
context switches.

In case of Idle Page Tracking, however, because the interface receives
contiguous page frames, the number of user/kernel context switches
increases as the monitoring target becomes complex and huge.  As a result,
the context switch overhead could be not negligible.

Moreover, DAMON is born to handle with the monitoring overhead.  Because
the core mechanism is pure logical, Idle Page Tracking users might be able
to implement the mechanism on their own, but it would be time consuming
and the user/kernel context switching will still more frequent than that
of DAMON.  Also, the kernel subsystems cannot use the logic in this case.

3. Page granularity working set size detection.

Until v22 of this patchset, this was categorized as the thing Idle Page
Tracking could do better, because DAMON basically maintains additional
metadata for each of the monitoring target regions.  So, in the page
granularity working set size detection use case, DAMON would incur (number
of monitoring target pages * size of metadata) memory overhead.  Size of
the single metadata item is about 54 bytes, so assuming 4KB pages, about
1.3% of monitoring target pages will be additionally used.

All essential metadata for Idle Page Tracking are embedded in 'struct
page' and page table entries.  Therefore, in this use case, only one
counter variable for working set size accounting is required if Idle Page
Tracking is used.

There are more details to consider, but roughly speaking, this is true in
most cases.

However, the situation changed from v23.  Now DAMON supports arbitrary
types of monitoring targets, which don't use the metadata.  Using that,
DAMON can do the working set size detection with no additional space
overhead but less user-kernel context switch.  A first draft for the
implementation of monitoring primitives for this usage is available in a
DAMON development tree[1].  An RFC patchset for it based on this patchset
will also be available soon.

Since v24, the arbitrary type support is dropped from this patchset
because this patchset doesn't introduce real use of the type.  You can
still get it from the DAMON development tree[2], though.

[1] https://github.com/sjp38/linux/tree/damon/pgidle_hack
[2] https://github.com/sjp38/linux/tree/damon/master

4. More future usecases

While Idle Page Tracking has tight coupling with base primitives (PG_Idle
and page table Accessed bits), DAMON is designed to be extensible for many
use cases and address spaces.  If you need some special address type or
want to use special h/w access check primitives, you can write your own
primitives for that and configure DAMON to use those.  Therefore, if your
use case could be changed a lot in future, using DAMON could be better.

Can I use both Idle Page Tracking and DAMON?
--------------------------------------------

Yes, though using them concurrently for overlapping memory regions could
result in interference to each other.  Nevertheless, such use case would
be rare or makes no sense at all.  Even in the case, the noise would bot
be really significant.  So, you can choose whatever you want depending on
the characteristics of your use cases.

More Information
================

We prepared a showcase web site[1] that you can get more information.
There are

- the official documentations[2],
- the heatmap format dynamic access pattern of various realistic workloads for
  heap area[3], mmap()-ed area[4], and stack[5] area,
- the dynamic working set size distribution[6] and chronological working set
  size changes[7], and
- the latest performance test results[8].

[1] https://damonitor.github.io/_index
[2] https://damonitor.github.io/doc/html/latest-damon
[3] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.0.png.html
[4] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.1.png.html
[5] https://damonitor.github.io/test/result/visual/latest/rec.heatmap.2.png.html
[6] https://damonitor.github.io/test/result/visual/latest/rec.wss_sz.png.html
[7] https://damonitor.github.io/test/result/visual/latest/rec.wss_time.png.html
[8] https://damonitor.github.io/test/result/perf/latest/html/index.html

Baseline and Complete Git Trees
===============================

The patches are based on the latest -mm tree, specifically
v5.14-rc1-mmots-2021-07-15-18-47 of https://github.com/hnaz/linux-mm.  You can
also clone the complete git tree:

    $ git clone git://github.com/sjp38/linux -b damon/patches/v34

The web is also available:
https://github.com/sjp38/linux/releases/tag/damon/patches/v34

Development Trees
-----------------

There are a couple of trees for entire DAMON patchset series and features
for future release.

- For latest release: https://github.com/sjp38/linux/tree/damon/master
- For next release: https://github.com/sjp38/linux/tree/damon/next

Long-term Support Trees
-----------------------

For people who want to test DAMON but using LTS kernels, there are another
couple of trees based on two latest LTS kernels respectively and
containing the 'damon/master' backports.

- For v5.4.y: https://github.com/sjp38/linux/tree/damon/for-v5.4.y
- For v5.10.y: https://github.com/sjp38/linux/tree/damon/for-v5.10.y

Amazon Linux Kernel Trees
-------------------------

DAMON is also merged in two public Amazon Linux kernel trees that based on
v5.4.y[1] and v5.10.y[2].

[1] https://github.com/amazonlinux/linux/tree/amazon-5.4.y/master/mm/damon
[2] https://github.com/amazonlinux/linux/tree/amazon-5.10.y/master/mm/damon

Git Tree for Diff of Patches
============================

For easy review of diff between different versions of each patch, I
prepared a git tree containing all versions of the DAMON patchset series:
https://github.com/sjp38/damon-patches

You can clone it and use 'diff' for easy review of changes between
different versions of the patchset.  For example:

    $ git clone https://github.com/sjp38/damon-patches && cd damon-patches
    $ diff -u damon/v33 damon/v34

Sequence Of Patches
===================

First three patches implement the core logics of DAMON.  The 1st patch
introduces basic sampling based hotness monitoring for arbitrary types of
targets.  Following two patches implement the core mechanisms for control
of overhead and accuracy, namely regions based sampling (patch 2) and
adaptive regions adjustment (patch 3).

Now the essential parts of DAMON is complete, but it cannot work unless
someone provides monitoring primitives for a specific use case.  The
following two patches make it just work for virtual address spaces
monitoring.  The 4th patch makes 'PG_idle' can be used by DAMON and the
5th patch implements the virtual memory address space specific monitoring
primitives using page table Accessed bits and the 'PG_idle' page flag.

Now DAMON just works for virtual address space monitoring via the kernel
space api.  To let the user space users can use DAMON, following four
patches add interfaces for them.  The 6th patch adds a tracepoint for
monitoring results.  The 7th patch implements a DAMON application kernel
module, namely damon-dbgfs, that simply wraps DAMON and exposes DAMON
interface to the user space via the debugfs interface.  The 8th patch
further exports pid of monitoring thread (kdamond) to user space for
easier cpu usage accounting, and the 9th patch makes the debugfs interface
to support multiple contexts.

Three patches for maintainability follows.  The 10th patch adds
documentations for both the user space and the kernel space.  The 11th
patch provides unit tests (based on the kunit) while the 12th patch adds
user space tests (based on the kselftest).

Finally, the last patch (13th) updates the MAINTAINERS file.

This patch (of 13):

DAMON is a data access monitoring framework for the Linux kernel.  The
core mechanisms of DAMON make it

 - accurate (the monitoring output is useful enough for DRAM level
   performance-centric memory management; It might be inappropriate for
   CPU cache levels, though),
 - light-weight (the monitoring overhead is normally low enough to be
   applied online), and
 - scalable (the upper-bound of the overhead is in constant range
   regardless of the size of target workloads).

Using this framework, hence, we can easily write efficient kernel space
data access monitoring applications.  For example, the kernel's memory
management mechanisms can make advanced decisions using this.
Experimental data access aware optimization works that incurring high
access monitoring overhead could again be implemented on top of this.

Due to its simple and flexible interface, providing user space interface
would be also easy.  Then, user space users who have some special
workloads can write personalized applications for better understanding and
optimizations of their workloads and systems.

===

Nevertheless, this commit is defining and implementing only basic access
check part without the overhead-accuracy handling core logic.  The basic
access check is as below.

The output of DAMON says what memory regions are how frequently accessed
for a given duration.  The resolution of the access frequency is
controlled by setting ``sampling interval`` and ``aggregation interval``.
In detail, DAMON checks access to each page per ``sampling interval`` and
aggregates the results.  In other words, counts the number of the accesses
to each region.  After each ``aggregation interval`` passes, DAMON calls
callback functions that previously registered by users so that users can
read the aggregated results and then clears the results.  This can be
described in below simple pseudo-code::

    init()
    while monitoring_on:
        for page in monitoring_target:
            if accessed(page):
                nr_accesses[page] += 1
        if time() % aggregation_interval == 0:
            for callback in user_registered_callbacks:
                callback(monitoring_target, nr_accesses)
            for page in monitoring_target:
                nr_accesses[page] = 0
        if time() % update_interval == 0:
            update()
        sleep(sampling interval)

The target regions constructed at the beginning of the monitoring and
updated after each ``regions_update_interval``, because the target regions
could be dynamically changed (e.g., mmap() or memory hotplug).  The
monitoring overhead of this mechanism will arbitrarily increase as the
size of the target workload grows.

The basic monitoring primitives for actual access check and dynamic target
regions construction aren't in the core part of DAMON.  Instead, it allows
users to implement their own primitives that are optimized for their use
case and configure DAMON to use those.  In other words, users cannot use
current version of DAMON without some additional works.

Following commits will implement the core mechanisms for the
overhead-accuracy control and default primitives implementations.

Link: https://lkml.kernel.org/r/20210716081449.22187-1-sj38.park@gmail.com
Link: https://lkml.kernel.org/r/20210716081449.22187-2-sj38.park@gmail.com
Signed-off-by: SeongJae Park <sjpark@amazon.de>
Reviewed-by: Leonard Foerster <foersleo@amazon.de>
Reviewed-by: Fernand Sieber <sieberf@amazon.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Amit Shah <amit@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Woodhouse <dwmw@amazon.com>
Cc: Marco Elver <elver@google.com>
Cc: Fan Du <fan.du@intel.com>
Cc: Greg Kroah-Hartman <greg@kroah.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Joe Perches <joe@perches.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Maximilian Heyne <mheyne@amazon.de>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Markus Boehme <markubo@amazon.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:24 -07:00
Marco Elver
c40c6e593b kfence: test: fail fast if disabled at boot 
Fail kfence_test fast if KFENCE was disabled at boot, instead of each test
case trying several seconds to allocate from KFENCE and failing.  KUnit
will fail all test cases if kunit_suite::init returns an error.

Even if KFENCE was disabled, we still want the test to fail, so that CI
systems that parse KUnit output will alert on KFENCE being disabled
(accidentally or otherwise).

Link: https://lkml.kernel.org/r/20210825105533.1247922-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reported-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
 2021-09-08 11:50:24 -07:00