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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-23 04:34:11 +08:00
linux-next/fs/proc
Alexey Dobriyan 81243eacfa cred: simpler, 1D supplementary groups
Current supplementary groups code can massively overallocate memory and
is implemented in a way so that access to individual gid is done via 2D
array.

If number of gids is <= 32, memory allocation is more or less tolerable
(140/148 bytes).  But if it is not, code allocates full page (!)
regardless and, what's even more fun, doesn't reuse small 32-entry
array.

2D array means dependent shifts, loads and LEAs without possibility to
optimize them (gid is never known at compile time).

All of the above is unnecessary.  Switch to the usual
trailing-zero-len-array scheme.  Memory is allocated with
kmalloc/vmalloc() and only as much as needed.  Accesses become simpler
(LEA 8(gi,idx,4) or even without displacement).

Maximum number of gids is 65536 which translates to 256KB+8 bytes.  I
think kernel can handle such allocation.

On my usual desktop system with whole 9 (nine) aux groups, struct
group_info shrinks from 148 bytes to 44 bytes, yay!

Nice side effects:

 - "gi->gid[i]" is shorter than "GROUP_AT(gi, i)", less typing,

 - fix little mess in net/ipv4/ping.c
   should have been using GROUP_AT macro but this point becomes moot,

 - aux group allocation is persistent and should be accounted as such.

Link: http://lkml.kernel.org/r/20160817201927.GA2096@p183.telecom.by
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-07 18:46:30 -07:00
..
array.c cred: simpler, 1D supplementary groups 2016-10-07 18:46:30 -07:00
base.c proc: fix timerslack_ns CAP_SYS_NICE check when adjusting self 2016-10-07 18:46:30 -07:00
cmdline.c fs/proc: don't use module_init for non-modular core code 2014-01-23 16:37:02 -08:00
consoles.c fs/proc: don't use module_init for non-modular core code 2014-01-23 16:37:02 -08:00
cpuinfo.c fs/proc: don't use module_init for non-modular core code 2014-01-23 16:37:02 -08:00
devices.c fs/proc: don't use module_init for non-modular core code 2014-01-23 16:37:02 -08:00
fd.c switch all procfs directories ->iterate_shared() 2016-05-02 19:49:30 -04:00
fd.h proc: Move proc_fd() to fs/proc/fd.h 2013-05-01 17:29:39 -04:00
generic.c proc: make proc entries inherit ownership from parent 2016-08-14 21:07:20 -07:00
inode.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2016-07-29 15:54:19 -07:00
internal.h proc: Convert proc_mount to use mount_ns. 2016-06-23 15:41:54 -05:00
interrupts.c fs/proc: don't use module_init for non-modular core code 2014-01-23 16:37:02 -08:00
Kconfig fs, proc: add help for CONFIG_PROC_CHILDREN 2015-07-17 16:39:52 -07:00
kcore.c fs/proc/kcore.c: Add bounce buffer for ktext data 2016-09-20 13:32:49 -07:00
kmsg.c fs/proc: don't use module_init for non-modular core code 2014-01-23 16:37:02 -08:00
loadavg.c fs/proc: don't use module_init for non-modular core code 2014-01-23 16:37:02 -08:00
Makefile fs/proc: Add compiler check for -Wno-override-init to support gcc < 4.2 2016-08-03 12:45:23 -04:00
meminfo.c meminfo: break apart a very long seq_printf with #ifdefs 2016-10-07 18:46:30 -07:00
namespaces.c switch all procfs directories ->iterate_shared() 2016-05-02 19:49:30 -04:00
nommu.c vfs: add seq_file_path() helper 2015-06-23 18:01:07 -04:00
page.c mm: rename _count, field of the struct page, to _refcount 2016-05-19 19:12:14 -07:00
proc_net.c proc: make proc entries inherit ownership from parent 2016-08-14 21:07:20 -07:00
proc_sysctl.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2016-10-06 09:52:23 -07:00
proc_tty.c proc: remove proc_tty_ldisc variable 2014-08-08 15:57:22 -07:00
root.c proc: Convert proc_mount to use mount_ns. 2016-06-23 15:41:54 -05:00
self.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
softirqs.c fs/proc: don't use module_init for non-modular core code 2014-01-23 16:37:02 -08:00
stat.c seq/proc: modify seq_put_decimal_[u]ll to take a const char *, not char 2016-10-07 18:46:30 -07:00
task_mmu.c mm, proc: fix region lost in /proc/self/smaps 2016-10-07 18:46:30 -07:00
task_nommu.c proc: revert /proc/<pid>/maps [stack:TID] annotation 2016-02-03 08:28:43 -08:00
thread_self.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
uptime.c cputime: Default implementation of nsecs -> cputime conversion 2014-03-13 15:56:43 +01:00
version.c fs/proc: don't use module_init for non-modular core code 2014-01-23 16:37:02 -08:00
vmcore.c crash_dump: Add vmcore_elf32_check_arch 2016-05-13 14:01:59 +02:00