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authorFrederic Weisbecker <fweisbec@gmail.com>2013-05-02 17:37:49 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2013-05-02 17:54:19 +0200
commitc032862fba51a3ca504752d3a25186b324c5ce83 (patch)
tree955dc2ba4ab3df76ecc2bb780ee84aca04967e8d /Documentation/vm
parentfda76e074c7737fc57855dd17c762e50ed526052 (diff)
parent8700c95adb033843fc163d112b9d21d4fda78018 (diff)
downloadlinux-c032862fba51a3ca504752d3a25186b324c5ce83.tar.bz2
Merge commit '8700c95adb03' into timers/nohz
The full dynticks tree needs the latest RCU and sched upstream updates in order to fix some dependencies. Merge a common upstream merge point that has these updates. Conflicts: include/linux/perf_event.h kernel/rcutree.h kernel/rcutree_plugin.h Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'Documentation/vm')
-rw-r--r--Documentation/vm/overcommit-accounting8
1 files changed, 7 insertions, 1 deletions
diff --git a/Documentation/vm/overcommit-accounting b/Documentation/vm/overcommit-accounting
index 706d7ed9d8d2..8eaa2fc4b8fa 100644
--- a/Documentation/vm/overcommit-accounting
+++ b/Documentation/vm/overcommit-accounting
@@ -8,7 +8,9 @@ The Linux kernel supports the following overcommit handling modes
default.
1 - Always overcommit. Appropriate for some scientific
- applications.
+ applications. Classic example is code using sparse arrays
+ and just relying on the virtual memory consisting almost
+ entirely of zero pages.
2 - Don't overcommit. The total address space commit
for the system is not permitted to exceed swap + a
@@ -18,6 +20,10 @@ The Linux kernel supports the following overcommit handling modes
pages but will receive errors on memory allocation as
appropriate.
+ Useful for applications that want to guarantee their
+ memory allocations will be available in the future
+ without having to initialize every page.
+
The overcommit policy is set via the sysctl `vm.overcommit_memory'.
The overcommit percentage is set via `vm.overcommit_ratio'.