Commit 4964cd41 authored Apr 26, 2010 by San Mehat Committed by Greg Kroah-Hartman Nov 30, 2011

staging: android: lowmemorykiller: Don't try to kill the same pid over and over



  Under certain circumstances, a process can take awhile to
handle a sig-kill (especially if it's in a scheduler group with
a very low share ratio). When this occurs, lowmemkiller returns
to vmscan indicating the process memory has been freed - even
though the process is still waiting to die. Since the memory
hasn't actually freed, lowmemkiller is called again shortly after,
and picks the same process to die; regardless of the fact that
it has already been 'scheduled' to die and the memory has already
been reported to vmscan as having been freed.

  Solution is to check fatal_signal_pending() on the selected
task, and if it's already pending destruction return; indicating
to vmscan that no resources were freed on this pass.

Signed-off-by: San Mehat <san@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

parent 3c762a49

drivers/staging/android/lowmemorykiller.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -133,6 +133,12 @@ static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask)
		p->pid, p->comm, oom_adj, tasksize);
		}
		if (selected) {
		if (fatal_signal_pending(selected)) {
		pr_warning("process %d is suffering a slow death\n",
		selected->pid);
		read_unlock(&tasklist_lock);
		return rem;
		}
		lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",
		selected->pid, selected->comm,
		selected_oom_adj, selected_tasksize);