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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2011-05-24 17:11:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-25 08:39:08 -0700
commit37b23e0525d393d48a7d59f870b3bc061a30ccdb (patch)
tree467e6fcd785108a21d836e1aad8fc1a68aa72e17 /arch
parentf62e00cc3a00bfbd394a79fc22b334c31f91bd5f (diff)
downloadlinux-linaro-stable-37b23e0525d393d48a7d59f870b3bc061a30ccdb.tar.gz
x86,mm: make pagefault killable
When an oom killing occurs, almost all processes are getting stuck at the following two points. 1) __alloc_pages_nodemask 2) __lock_page_or_retry 1) is not very problematic because TIF_MEMDIE leads to an allocation failure and getting out from page allocator. 2) is more problematic. In an OOM situation, zones typically don't have page cache at all and memory starvation might lead to greatly reduced IO performance. When a fork bomb occurs, TIF_MEMDIE tasks don't die quickly, meaning that a fork bomb may create new process quickly rather than the oom-killer killing it. Then, the system may become livelocked. This patch makes the pagefault interruptible by SIGKILL. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/mm/fault.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index bcb394dfbb35..f7a2a054a3c0 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -965,7 +965,7 @@ do_page_fault(struct pt_regs *regs, unsigned long error_code)
struct mm_struct *mm;
int fault;
int write = error_code & PF_WRITE;
- unsigned int flags = FAULT_FLAG_ALLOW_RETRY |
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
(write ? FAULT_FLAG_WRITE : 0);
tsk = current;
@@ -1139,6 +1139,16 @@ good_area:
}
/*
+ * Pagefault was interrupted by SIGKILL. We have no reason to
+ * continue pagefault.
+ */
+ if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) {
+ if (!(error_code & PF_USER))
+ no_context(regs, error_code, address);
+ return;
+ }
+
+ /*
* Major/minor page fault accounting is only done on the
* initial attempt. If we go through a retry, it is extremely
* likely that the page will be found in page cache at that point.