Willy Tarreau wrote:
Hi Nick,
On Wed, Sep 20, 2006 at 03:42:06AM +1000, Nick Piggin wrote:
[cut -pre3 advertisement]
I wonder if 2.4 doesn't need the memory ordering fix to prevent pagecache
corruption in reclaim? (http://www.gatago.com/linux/kernel/14682626.html)
What would need to be done is to test page_count before testing PageDirty,
and putting an smp_rmb between the two.
I've read the thread, and Linus proposed to add an smp_wmb() in
set_page_dirty() too.
I think that isn't needed because put_page is a RMW, which is defined
to order memory. And presumably you wouldn't set the page dirty without
a reference to the page.
I see that an smp_rmb() is already present
in shrink_cache() with the adequate comment.
So there is! My mistake then, I was confused and looking at
try_to_swap_out, but I see that doesn't actually free the page. Fine,
I think 2.4 is OK then.
--
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]
