![]() | ||||||||||
Messages in this thread |
On Sat, Nov 17, 2001 at 10:24:44PM -0800, Linus Torvalds wrote: > > On Sun, 18 Nov 2001, Andrea Arcangeli wrote: > > > > I also agree the patch shouldn't matter, but one suspect thing is the > > fact add_to_swap_cache goes to clobber in a non atomic manner the page > > lock. > > .. you mean __add_to_page_cache(), not add_to_swap_cache(). > > And nope, not really. It does use plain stores to page->flags, and I agree > that it is ugly, but if the page was locked before calling it, all the > stores will be with the PG_lock bit set - and even plain stores _are_ > documented to be atomic on x86 (and on all other reasonable architectures > too). I know all is right if GCC just overwrites the page->flags with data that keeps PG_locked set. But GCC doesn't guarantee that. GCC can as well do: flags = page->flags; page->flags = 0; change flags here page->flags = flags probably gcc doesn't, but that's still a kernel bug. Andrea - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | |||||||||
| Last update: 2005-03-22 12:13 [from the cache] ©2003-2008 | ||||||||||