Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[pandora-kernel.git] / Documentation / sysctl / vm.txt

diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index c4de635..a6e360d 100644 (file)
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -32,6 +32,8 @@ Currently, these files are in /proc/sys/vm:
 - legacy_va_layout
 - lowmem_reserve_ratio
 - max_map_count
+- memory_failure_early_kill
+- memory_failure_recovery
 - min_free_kbytes
 - min_slab_ratio
 - min_unmapped_ratio
@@ -53,7 +55,6 @@ Currently, these files are in /proc/sys/vm:
 - vfs_cache_pressure
 - zone_reclaim_mode
 
-
 ==============================================================
 
 block_dump
@@ -275,6 +276,44 @@ e.g., up to one or two maps per allocation.
 
 The default value is 65536.
 
+=============================================================
+
+memory_failure_early_kill:
+
+Control how to kill processes when uncorrected memory error (typically
+a 2bit error in a memory module) is detected in the background by hardware
+that cannot be handled by the kernel. In some cases (like the page
+still having a valid copy on disk) the kernel will handle the failure
+transparently without affecting any applications. But if there is
+no other uptodate copy of the data it will kill to prevent any data
+corruptions from propagating.
+
+1: Kill all processes that have the corrupted and not reloadable page mapped
+as soon as the corruption is detected.  Note this is not supported
+for a few types of pages, like kernel internally allocated data or
+the swap cache, but works for the majority of user pages.
+
+0: Only unmap the corrupted page from all processes and only kill a process
+who tries to access it.
+
+The kill is done using a catchable SIGBUS with BUS_MCEERR_AO, so processes can
+handle this if they want to.
+
+This is only active on architectures/platforms with advanced machine
+check handling and depends on the hardware capabilities.
+
+Applications can override this setting individually with the PR_MCE_KILL prctl
+
+==============================================================
+
+memory_failure_recovery
+
+Enable memory failure recovery (when supported by the platform)
+
+1: Attempt recovery.
+
+0: Always panic on a memory failure.
+
 ==============================================================
 
 min_free_kbytes:
@@ -585,7 +624,9 @@ caching of directory and inode objects.
 At the default value of vfs_cache_pressure=100 the kernel will attempt to
 reclaim dentries and inodes at a "fair" rate with respect to pagecache and
 swapcache reclaim.  Decreasing vfs_cache_pressure causes the kernel to prefer
-to retain dentry and inode caches.  Increasing vfs_cache_pressure beyond 100
+to retain dentry and inode caches. When vfs_cache_pressure=0, the kernel will
+never reclaim dentries and inodes due to memory pressure and this can easily
+lead to out-of-memory conditions. Increasing vfs_cache_pressure beyond 100
 causes the kernel to prefer to reclaim dentries and inodes.
 
 ==============================================================