• KOSAKI Motohiro's avatar
    x86,mm: make pagefault killable · 37b23e05
    KOSAKI Motohiro authored
    
    
    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: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
    Reviewed-by: default avatarKAMEZAWA 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: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    37b23e05
fault.c 27.8 KB