Nick Piggin wrote:
William Lee Irwin III wrote:
On Mon, Jun 27, 2005 at 04:32:38PM +1000, Nick Piggin wrote:
+static inline struct page *page_cache_get_speculative(struct page
**pagep)
+{
+ struct page *page;
+
+ preempt_disable();
+ page = *pagep;
+ if (!page)
+ goto out_failed;
+
+ if (unlikely(get_page_testone(page))) {
+ /* Picked up a freed page */
+ __put_page(page);
+ goto out_failed;
+ }
So you pick up 0->1 refcount transitions.
Yep ie. a page that's freed or being freed.
Oh, one thing it does need is a check for PageFree(), so it also
picks up 1->2 and other transitions without freeing the free page
if the put()s are done out of order. Maybe that's what you were
alluding to.
I'll add that.
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
