On 06/06/2014 07:16 PM, Linus Torvalds wrote: >> I have no evidence that its lack is responsible for the mm/filemap.c:202 >> > BUG_ON(page_mapped(page)) in __delete_from_page_cache() found by trinity, >> > and I am not optimistic that it will fix it. But I have found no other >> > explanation, and ACCESS_ONCE() here will surely not hurt. > The patch looks obviously correct to me, although like you, I have no > real reason to believe it really fixes anything. But we definitely > should just load it once, since it's very much an optimistic load done > before we take the real lock and re-compare. > > I'm somewhat dubious whether it actually would change code generation > - it doesn't change anything with the test-configuration I tried with > - but it's unquestionably a good patch. And hey, maybe some > configurations have sufficiently different code generation that gcc > actually _can_ sometimes do reloads, perhaps explaining why some > people see problems. So it's certainly worth testing even if it > doesn't make any change to code generation with *my* compiler and > config.. I'm seeing the same code generated here as well. I won't carry the patch unless Andrew/Linus take it so it won't hide possible bugs that trinity might stumble on. Thanks, Sasha -- 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>