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| author | Michael Kerrisk <mtk.manpages@gmail.com> | 2017-01-16 15:43:37 +1300 |
|---|---|---|
| committer | Michael Kerrisk <mtk.manpages@gmail.com> | 2017-01-16 22:07:14 +1300 |
| commit | 4fb6ed947dd7097b99286060464c922fc179f94d (patch) | |
| tree | 19df9cf4fdfcf233b8c36e4c8b4c4658ea2c3dd2 | |
| parent | b017f51b94af908013e977df60f3038f075e487d (diff) | |
| download | man-pages-4fb6ed947dd7097b99286060464c922fc179f94d.tar.gz | |
proc.5: Document /proc/sys/vm/admin_reserve_kbytes
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
| -rw-r--r-- | man5/proc.5 | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/man5/proc.5 b/man5/proc.5 index eebebaeef4..351d684056 100644 --- a/man5/proc.5 +++ b/man5/proc.5 @@ -4887,6 +4887,33 @@ On some systems, it is not present. This directory contains files for memory management tuning, buffer and cache management. .TP +.IR /proc/sys/vm/admin_reserve_kbytes " (since Linux 3.10)" +.\" commit 4eeab4f5580d11bffedc697684b91b0bca0d5009 +This file defines the amount of free memory (in KiB) on the system that +that should be reserved for users with the capability +.BR CAP_SYS_ADMIN . + +The default value in this file is the minimum of [3% of free pages, 8MiB] +expressed as KiB. +The default is intended to provide enough for the superuser +to log in and kill a process, if necessary, +under the default overcommit 'guess' mode (i.e., 0 in +.IR /proc/sys/vm/overcommit_memory ). + +Systems running in "overcommit never" mode (i.e., 2 in +.IR /proc/sys/vm/overcommit_memory ) +should increase the value in this file to account +for the full virtual memory size of the programs used to recover (e.g., +.BR login (1) +.BR ssh (1), +and +.BR top (1)) +Otherwise, the superuser may not be able to log in to recover the system. +For example, on x86_64 a suitable value is 131072 (128MiB reserved). + +Changing the value in this file takes effect whenever +an application requests memory. +.TP .IR /proc/sys/vm/compact_memory " (since Linux 2.6.35)" When 1 is written to this file, all zones are compacted such that free memory is available in contiguous blocks where possible. |