On Fri, Apr 09, 2010 at 02:11:08PM -0400, Chris Mason wrote: > On Fri, Apr 09, 2010 at 01:05:05PM -0500, Eric Sandeen wrote: > > Chris Mason wrote: > > > > > shrink_zone on my box isn't 500 bytes, but lets try the easy stuff > > > first. This is against .34, if you have any trouble applying to .32, > > > just add the word noinline after the word static on the function > > > definitions. > > > > > > This makes shrink_zone disappear from my check_stack.pl output. > > > Basically I think the compiler is inlining the shrink_active_zone and > > > shrink_inactive_zone code into shrink_zone. > > > > > > -chris > > > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > > index 79c8098..c70593e 100644 > > > --- a/mm/vmscan.c > > > +++ b/mm/vmscan.c > > > @@ -620,7 +620,7 @@ static enum page_references page_check_references(struct page *page, > > > /* > > > * shrink_page_list() returns the number of reclaimed pages > > > */ > > > -static unsigned long shrink_page_list(struct list_head *page_list, > > > +static noinline unsigned long shrink_page_list(struct list_head *page_list, > > > > FWIW akpm suggested that I add: > > > > /* > > * Rather then using noinline to prevent stack consumption, use > > * noinline_for_stack instead. For documentaiton reasons. > > */ > > #define noinline_for_stack noinline > > > > so maybe for a formal submission that'd be good to use. > > Oh yeah, I forgot about that one. If the patch actually helps we can > switch it. Well, given that the largest stack overflow reported was about 800 bytes, I don't think it's enough. All the fat has been trimmed from XFS long ago, and there isn't that much in the generic code paths to trim. And if we consider that this isn't including a significant storage subsystem (i.e. NFS on top and stacked DM+MD+FC below), then trimming a few hundred bytes is not enough to prevent an 8k stack being blown sky high. That is why I was saying I'm not sure what the best way to solve the problem is - I've got a couple of ideas for fixing the problem in XFS once and for all, but I'm not sure if they will fly or not yet, let alone written any code.... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>