On Sat, Sep 20, 2014 at 10:23 AM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Sat, 20 Sep 2014 09:25:01 +0400 Konstantin Khlebnikov <koct9i@xxxxxxxxx> wrote: > >> > >> > So I'm going to send "fix for >> > mm-balloon_compaction-use-common-page-ballooning-v2" to Linus >> > separately, but it has no changelog at all. >> >> Probably it would be better if you drop everything except actually >> fixes and stresstest. This is gone too far, now balloon won't compile >> in the middle of patchset. Just tell me and I'll redo the rest. > > I think it's best if I drop everything: > > mm-balloon_compaction-ignore-anonymous-pages.patch > mm-balloon_compaction-keep-ballooned-pages-away-from-normal-migration-path.patch > mm-balloon_compaction-isolate-balloon-pages-without-lru_lock.patch > selftests-vm-transhuge-stress-stress-test-for-memory-compaction.patch > mm-introduce-common-page-state-for-ballooned-memory.patch > mm-balloon_compaction-use-common-page-ballooning.patch > mm-balloon_compaction-general-cleanup.patch > mm-balloon_compaction-use-common-page-ballooning-v2-fix-1.patch > > Please go through it and send out a new version? > > I've found yet another bug in this code. It seems here is a nest. balloon_page_dequeue can race with balloon_page_isolate: balloon_page_isolate can remove page from list between llist_for_each_entry_safe and trylock_page in balloon_page_dequeue. balloon_page_dequeue runs under mutex_lock(&vb->balloon_lock); both of them lock page using trylock_page so race is tight but it is not impossible. Probably it's really easier to rewrite it than to fix bugs one by one =/ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>