diff options
| author | Charan Teja Reddy <charante@codeaurora.org> | 2021-09-02 14:59:59 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-09-03 09:58:17 -0700 |
| commit | 65d759c8f9f57b96c199f3fe5cfb93ac7da095e9 (patch) | |
| tree | aae99d3d34c7279a96895541e0422d7ead7bfb34 /Documentation/admin-guide/sysctl | |
| parent | e1e92bfa3825b72be4957f9fef267b3106d20aa6 (diff) | |
mm: compaction: support triggering of proactive compaction by user
The proactive compaction[1] gets triggered for every 500msec and run
compaction on the node for COMPACTION_HPAGE_ORDER (usually order-9) pages
based on the value set to sysctl.compaction_proactiveness. Triggering the
compaction for every 500msec in search of COMPACTION_HPAGE_ORDER pages is
not needed for all applications, especially on the embedded system
usecases which may have few MB's of RAM. Enabling the proactive
compaction in its state will endup in running almost always on such
systems.
Other side, proactive compaction can still be very much useful for getting
a set of higher order pages in some controllable manner(controlled by
using the sysctl.compaction_proactiveness). So, on systems where enabling
the proactive compaction always may proove not required, can trigger the
same from user space on write to its sysctl interface. As an example, say
app launcher decide to launch the memory heavy application which can be
launched fast if it gets more higher order pages thus launcher can prepare
the system in advance by triggering the proactive compaction from
userspace.
This triggering of proactive compaction is done on a write to
sysctl.compaction_proactiveness by user.
[1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=facdaa917c4d5a376d09d25865f5a863f906234a
[akpm@linux-foundation.org: tweak vm.rst, per Mike]
Link: https://lkml.kernel.org/r/1627653207-12317-1-git-send-email-charante@codeaurora.org
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Rafael Aquini <aquini@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Nitin Gupta <nigupta@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/admin-guide/sysctl')
| -rw-r--r-- | Documentation/admin-guide/sysctl/vm.rst | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst index 003d5cc3751b..5e795202111f 100644 --- a/Documentation/admin-guide/sysctl/vm.rst +++ b/Documentation/admin-guide/sysctl/vm.rst @@ -118,7 +118,8 @@ compaction_proactiveness This tunable takes a value in the range [0, 100] with a default value of 20. This tunable determines how aggressively compaction is done in the -background. Setting it to 0 disables proactive compaction. +background. Write of a non zero value to this tunable will immediately +trigger the proactive compaction. Setting it to 0 disables proactive compaction. Note that compaction has a non-trivial system-wide impact as pages belonging to different processes are moved around, which could also lead |