No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Johannes Weiner 42a3003535 mm: memcontrol: fix recursive statistics correctness & scalabilty
Right now, when somebody needs to know the recursive memory statistics
and events of a cgroup subtree, they need to walk the entire subtree and
sum up the counters manually.

There are two issues with this:

1. When a cgroup gets deleted, its stats are lost. The state counters
   should all be 0 at that point, of course, but the events are not.
   When this happens, the event counters, which are supposed to be
   monotonic, can go backwards in the parent cgroups.

2. During regular operation, we always have a certain number of lazily
   freed cgroups sitting around that have been deleted, have no tasks,
   but have a few cache pages remaining. These groups' statistics do not
   change until we eventually hit memory pressure, but somebody
   watching, say, memory.stat on an ancestor has to iterate those every
   time.

This patch addresses both issues by introducing recursive counters at
each level that are propagated from the write side when stats change.

Upward propagation happens when the per-cpu caches spill over into the
local atomic counter.  This is the same thing we do during charge and
uncharge, except that the latter uses atomic RMWs, which are more
expensive; stat changes happen at around the same rate.  In a sparse
file test (page faults and reclaim at maximum CPU speed) with 5 cgroup
nesting levels, perf shows __mod_memcg_page state at ~1%.

Link: http://lkml.kernel.org/r/20190412151507.2769-4-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 19:52:53 -07:00
arch arch: remove <asm/sizes.h> and <asm-generic/sizes.h> 2019-05-14 19:52:52 -07:00
block
certs
crypto
Documentation ipc: allow boot time extension of IPCMNI from 32k to 16M 2019-05-14 19:52:52 -07:00
drivers drivers/virt/fsl_hypervisor.c: prevent integer overflow in ioctl 2019-05-14 19:52:52 -07:00
fs fs/block_dev.c: Remove duplicate header 2019-05-14 19:52:52 -07:00
include mm: memcontrol: fix recursive statistics correctness & scalabilty 2019-05-14 19:52:53 -07:00
init mm: shuffle initial free memory to improve memory-side-cache utilization 2019-05-14 19:52:48 -07:00
ipc ipc: do cyclic id allocation for the ipc object. 2019-05-14 19:52:52 -07:00
kernel panic/reboot: allow specifying reboot_mode for panic only 2019-05-14 19:52:51 -07:00
lib tools/testing/selftests/sysctl/sysctl.sh: add proc_do_large_bitmap() test case 2019-05-14 19:52:51 -07:00
LICENSES
mm mm: memcontrol: fix recursive statistics correctness & scalabilty 2019-05-14 19:52:53 -07:00
net net: replace CONFIG_DEBUG_KERNEL with CONFIG_DEBUG_MISC 2019-05-14 19:52:50 -07:00
samples
scripts scripts/gdb: print cached rate in lx-clk-summary 2019-05-14 19:52:52 -07:00
security
sound
tools tools/testing/selftests/sysctl/sysctl.sh: add proc_do_large_bitmap() test case 2019-05-14 19:52:51 -07:00
usr
virt mm/mmu_notifier: convert user range->blockable to helper function 2019-05-14 09:47:49 -07:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS - Core Frameworks 2019-05-14 10:39:08 -07:00
Makefile
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.