On (28/09/07 20:25), Peter Zijlstra didst pronounce: > > On Fri, 2007-09-28 at 11:20 -0700, Christoph Lameter wrote: > > > > start 2 processes that each mmap a separate 64M file, and which does > > > sequential writes on them. start a 3th process that does the same with > > > 64M anonymous. > > > > > > wait for a while, and you'll see order=1 failures. > > > > Really? That means we can no longer even allocate stacks for forking. > > > > Its surprising that neither lumpy reclaim nor the mobility patches can > > deal with it? Lumpy reclaim should be able to free neighboring pages to > > avoid the order 1 failure unless there are lots of pinned pages. > > > > I guess then that lots of pages are pinned through I/O? > > memory got massively fragemented, as anti-frag gets easily defeated. > setting min_free_kbytes to 12M does seem to solve it - it forces 2 max The 12MB is related to the size of pageblock_order. I strongly suspect that if you forced pageblock_order to be something like 4 or 5, the min_free_kbytes would not need to be raised. The current values are selected based on the hugepage size. > order blocks to stay available, so we don't mix types. however 12M on > 128M is rather a lot. > > its still on my todo list to look at it further.. > -- -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
