mm: limit growth of 3% hardcoded other user reserve

[cascardo/linux.git] / Documentation / vm / overcommit-accounting

diff --git a/Documentation/vm/overcommit-accounting b/Documentation/vm/overcommit-accounting
index 706d7ed..8eaa2fc 100644 (file)
--- 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'.