diff options
| author | Rik van Riel <riel@redhat.com> | 2011-09-01 15:26:50 -0400 |
|---|---|---|
| committer | Colin Cross <ccross@android.com> | 2013-09-19 13:53:19 -0500 |
| commit | 2f42fa9141974d917c5a85fc484e48f53cf7ec71 (patch) | |
| tree | 50198cfca0ce4d96a2cb9b33511ce7657cfb8a77 /kernel/sysctl.c | |
| parent | bbf5538ee0e4c30ba9b4556f9699ed5f31df67da (diff) | |
add extra free kbytes tunable
Add a userspace visible knob to tell the VM to keep an extra amount
of memory free, by increasing the gap between each zone's min and
low watermarks.
This is useful for realtime applications that call system
calls and have a bound on the number of allocations that happen
in any short time period. In this application, extra_free_kbytes
would be left at an amount equal to or larger than than the
maximum number of allocations that happen in any burst.
It may also be useful to reduce the memory use of virtual
machines (temporarily?), in a way that does not cause memory
fragmentation like ballooning does.
[ccross]
Revived for use on old kernels where no other solution exists.
The tunable will be removed on kernels that do better at avoiding
direct reclaim.
Change-Id: I765a42be8e964bfd3e2886d1ca85a29d60c3bb3e
Signed-off-by: Rik van Riel<riel@redhat.com>
Signed-off-by: Colin Cross <ccross@android.com>
Diffstat (limited to 'kernel/sysctl.c')
| -rw-r--r-- | kernel/sysctl.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 1a07798c9146..6f562baf5f4a 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -105,6 +105,7 @@ extern char core_pattern[]; extern unsigned int core_pipe_limit; #endif extern int pid_max; +extern int extra_free_kbytes; extern int min_free_order_shift; extern int pid_max_min, pid_max_max; extern int percpu_pagelist_fraction; @@ -1267,6 +1268,14 @@ static struct ctl_table vm_table[] = { .extra1 = &zero, }, { + .procname = "extra_free_kbytes", + .data = &extra_free_kbytes, + .maxlen = sizeof(extra_free_kbytes), + .mode = 0644, + .proc_handler = min_free_kbytes_sysctl_handler, + .extra1 = &zero, + }, + { .procname = "min_free_order_shift", .data = &min_free_order_shift, .maxlen = sizeof(min_free_order_shift), |