On Tue, May 17, 2011 at 2:00 AM, Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote: > On Sun, May 15, 2011 at 12:12:36PM -0400, Andrew Lutomirski wrote: >> On Sun, May 15, 2011 at 11:27 AM, Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote: >> >> That was probably because one of my testcases creates a 1.4GB file on >> ramfs. (I can provoke the problem without doing evil things like >> that, but the test script is rather reliable at killing my system and >> it works fine on my other machines.) > > Ah I didn't read your first email.. I'm now running > > ./test_mempressure.sh 1500 1400 1 > > with mem=2G and no swap, but cannot reproduce OOM. Do you have a Sandy Bridge laptop? There was a recent thread on lkml suggesting that only Sandy Bridge laptops saw this problem. Although there's something else needed to trigger it, because I can't do it from an initramfs I made that tried to show this problem. > > What's your kconfig? Attached. This is 2.6.38.6. > >> If you want, I can try to generate a trace that isn't polluted with >> the evil ramfs file. > > No, thanks. However it would be valuable if you can retry with this > patch _alone_ (without the "if (need_resched()) return false;" change, > as I don't see how it helps your case). > > @@ -2286,7 +2290,7 @@ static bool sleeping_prematurely(pg_data_t > *pgdat, int order, long remaining, > * must be balanced > */ > if (order) > - return pgdat_balanced(pgdat, balanced, classzone_idx); > + return !pgdat_balanced(pgdat, balanced, classzone_idx); > else > return !all_zones_ok; > } Done. I logged in, added swap, and ran a program that allocated 1900MB of RAM and memset it. The system lagged a bit but survived. kswapd showed 10% CPU (which is odd, IMO, since I'm using aesni-intel and I think that all the crypt happens in kworker when aesni-intel is in use). Then I started Firefox, loaded gmail, and ran test_mempressure.sh. Kaboom! (I.e. system was hung) SysRq-F saved the system and produced the attached dump. I had 6GB swap available, so there shouldn't have been any OOM. --Andy
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