Currently the per cpu counter's batch size for memory accounting is
configured as twice the number of cpus in the system. However, for
system with very large memory, it is more appropriate to make it
proportional to the memory size per cpu in the system.
For example, for a x86_64 system with 64 cpus and 128 GB of memory, the
batch size is only 2*64 pages (0.5 MB). So any memory accounting
changes of more than 0.5MB will overflow the per cpu counter into the
global counter. Instead, for the new scheme, the batch size is
configured to be 0.4% of the memory/cpu = 8MB (128 GB/64 /256), which is
more inline with the memory size.
I've done a repeated brk test of 800KB (from will-it-scale test suite)
with 80 concurrent processes on a 4 socket Westmere machine with a total
of 40 cores. Without the patch, about 80% of cpu is spent on spin-lock
contention within the vm_committed_as counter. With the patch, there's
a 73x speedup on the benchmark and the lock contention drops off almost
entirely.
[akpm@linux-foundation.org: fix section mismatch]
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Answering the question "how much space remains in the page->flags" is
time-consuming. mminit_loglevel can help answer the question but it
does not take last_nid information into account. This patch corrects it
and while there it corrects the messages related to page flag usage,
pgshifts and node/zone id. When applied the relevant output looks
something like this but will depend on the kernel configuration.
mminit::pageflags_layout_widths Section 0 Node 9 Zone 2 Lastnid 9 Flags 25
mminit::pageflags_layout_shifts Section 19 Node 9 Zone 2 Lastnid 9
mminit::pageflags_layout_pgshifts Section 0 Node 55 Zone 53 Lastnid 44
mminit::pageflags_layout_nodezoneid Node/Zone ID: 64 -> 53
mminit::pageflags_layout_usage location: 64 -> 44 layout 44 -> 25 unused 25 -> 0 page-flags
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The files changed within are only using the EXPORT_SYMBOL
macro variants. They are not using core modular infrastructure
and hence don't need module.h but only the export.h header.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
mminit_loglevel is now used from mminit_verify_zonelist <- build_all_zonelists <-
1. online_pages <- memory_block_action <- memory_block_change_state <- store_mem_state (sys handler)
2. numa_zonelist_order_handler (proc handler)
so it cannot be annotated __meminit - drop it
fixes following section mismatch warning:
WARNING: vmlinux.o(.text+0x71628): Section mismatch in reference from the function mminit_verify_zonelist() to the variable .meminit.data:mminit_loglevel
The function mminit_verify_zonelist() references
the variable __meminitdata mminit_loglevel.
This is often because mminit_verify_zonelist lacks a __meminitdata
annotation or the annotation of mminit_loglevel is wrong.
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
gcc-3.2:
mm/mm_init.c:77:1: directives may not be used inside a macro argument
mm/mm_init.c:76:47: unterminated argument list invoking macro "mminit_dprintk"
mm/mm_init.c: In function `mminit_verify_pageflags_layout':
mm/mm_init.c:80: `mminit_dprintk' undeclared (first use in this function)
mm/mm_init.c:80: (Each undeclared identifier is reported only once
mm/mm_init.c:80: for each function it appears in.)
mm/mm_init.c:80: syntax error before numeric constant
Also fix a typo in a comment.
Reported-by: Adrian Bunk <bunk@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a kobject to create /sys/kernel/mm when sysfs is mounted. The kobject
will exist regardless. This will allow for the hugepage related sysfs
directories to exist under the mm "subsystem" directory. Add an ABI file
appropriately.
[kosaki.motohiro@jp.fujitsu.com: fix build]
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Towards the end of putting all core mm initialization in mm_init.c, I
plan on putting the creation of a mm kobject in a function in that file.
However, the file is currently only compiled if CONFIG_DEBUG_MEMORY_INIT
is set. Remove this dependency, but put the code under an #ifdef on the
same config option. This should result in no functional changes.
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch prints out the zonelists during boot for manual verification by the
user if the mminit_loglevel is MMINIT_VERIFY or higher.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Print out information on how the page flags are being used if mminit_loglevel
is MMINIT_VERIFY or higher and unconditionally performs sanity checks on the
flags regardless of loglevel.
When the page flags are updated with section, node and zone information, a
check are made to ensure the values can be retrieved correctly. Finally we
confirm that pfn_to_page and page_to_pfn are the correct inverse functions.
[akpm@linux-foundation.org: fix printk warnings]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Boot initialisation is very complex, with significant numbers of
architecture-specific routines, hooks and code ordering. While significant
amounts of the initialisation is architecture-independent, it trusts the data
received from the architecture layer. This is a mistake, and has resulted in
a number of difficult-to-diagnose bugs.
This patchset adds some validation and tracing to memory initialisation. It
also introduces a few basic defensive measures. The validation code can be
explicitly disabled for embedded systems.
This patch:
Add additional debugging and verification code for memory initialisation.
Once enabled, the verification checks are always run and when required
additional debugging information may be outputted via a mminit_loglevel=
command-line parameter.
The verification code is placed in a new file mm/mm_init.c. Ideally other mm
initialisation code will be moved here over time.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
