On Mon, 2010-03-29 at 20:37 +0200, Andrea Arcangeli wrote: > From: Andrea Arcangeli <aarcange@xxxxxxxxxx> > > PG_buddy can be converted to page->_count == -1. So the PG_compound_lock can be > added to page->flags without overflowing (because of the section bits > increasing) with CONFIG_X86_PAE=y. This seems to break the assumption that all free pages have a zero page count relied upon by things like page_cache_get_speculative(). What if a page-cache pages gets freed and used as a head in the buddy list while a concurrent lockless page-cache lookup tries to get a page ref? -- 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>