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authorJerome Marchand <jmarchan@redhat.com>2014-01-21 15:49:14 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-21 16:19:44 -0800
commit49f0ce5f92321cdcf741e35f385669a421013cb7 (patch)
treed41c5a2283b32be69840cb8722ffd8cd8c38a1b0 /mm/nommu.c
parentaec6a8889a98a0cd58357cd0937a25189908f191 (diff)
downloadlwn-49f0ce5f92321cdcf741e35f385669a421013cb7.tar.gz
lwn-49f0ce5f92321cdcf741e35f385669a421013cb7.zip
mm: add overcommit_kbytes sysctl variable
Some applications that run on HPC clusters are designed around the availability of RAM and the overcommit ratio is fine tuned to get the maximum usage of memory without swapping. With growing memory, the 1%-of-all-RAM grain provided by overcommit_ratio has become too coarse for these workload (on a 2TB machine it represents no less than 20GB). This patch adds the new overcommit_kbytes sysctl variable that allow a much finer grain. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix nommu build] Signed-off-by: Jerome Marchand <jmarchan@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/nommu.c')
-rw-r--r--mm/nommu.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/nommu.c b/mm/nommu.c
index fec093adad9c..8740213b1647 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -60,6 +60,7 @@ unsigned long highest_memmap_pfn;
struct percpu_counter vm_committed_as;
int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
int sysctl_overcommit_ratio = 50; /* default is 50% */
+unsigned long sysctl_overcommit_kbytes __read_mostly;
int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */