Commit:     2b45ab3398a0ba119b1f672c7c56fd5a431b7f0a
Parent:     2b744c01a54fe0c9974ff1b29522f25f07084053
Author:     David Rientjes <[EMAIL PROTECTED]>
AuthorDate: Sun May 6 14:50:00 2007 -0700
Committer:  Linus Torvalds <[EMAIL PROTECTED]>
CommitDate: Mon May 7 12:12:55 2007 -0700

    oom: fix constraint deadlock
    Fixes a deadlock in the OOM killer for allocations that are not
    Before the OOM killer checks for the allocation constraint, it takes
    constrained_alloc() iterates through each zone in the allocation zonelist
    and calls cpuset_zone_allowed_softwall() to determine whether an allocation
    for gfp_mask is possible.  If a zone's node is not in the OOM-triggering
    task's mems_allowed, it is not exiting, and we did not fail on a
    __GFP_HARDWALL allocation, cpuset_zone_allowed_softwall() attempts to take
    callback_mutex to check the nearest exclusive ancestor of current's cpuset.
     This results in deadlock.
    We now take callback_mutex after iterating through the zonelist since we
    don't need it yet.
    Cc: Andi Kleen <[EMAIL PROTECTED]>
    Cc: Nick Piggin <[EMAIL PROTECTED]>
    Cc: Christoph Lameter <[EMAIL PROTECTED]>
    Cc: Martin J. Bligh <[EMAIL PROTECTED]>
    Signed-off-by: David Rientjes <[EMAIL PROTECTED]>
    Signed-off-by: Andrew Morton <[EMAIL PROTECTED]>
    Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]>
 mm/oom_kill.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 038d223..a700141 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -399,6 +399,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t 
gfp_mask, int order)
        struct task_struct *p;
        unsigned long points = 0;
        unsigned long freed = 0;
+       int constraint;
        blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
        if (freed > 0)
@@ -416,14 +417,15 @@ void out_of_memory(struct zonelist *zonelist, gfp_t 
gfp_mask, int order)
        if (sysctl_panic_on_oom == 2)
                panic("out of memory. Compulsory panic_on_oom is selected.\n");
-       cpuset_lock();
-       read_lock(&tasklist_lock);
         * Check if there were limitations on the allocation (only relevant for
         * NUMA) that may require different handling.
-       switch (constrained_alloc(zonelist, gfp_mask)) {
+       constraint = constrained_alloc(zonelist, gfp_mask);
+       cpuset_lock();
+       read_lock(&tasklist_lock);
+       switch (constraint) {
                oom_kill_process(current, points,
                                "No available memory (MPOL_BIND)");
To unsubscribe from this list: send the line "unsubscribe git-commits-head" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at

Reply via email to