Trond Myklebust wrote:
On Mon, 2005-12-05 at 16:18 -0500, Trond Myklebust wrote:
On Tue, 2005-12-06 at 07:52 +1100, Nick Piggin wrote:
The VM doesn't expect to have to rely on pdflush to write out pages
for it. ->writepage should be enough. Adding wakeup_pdflush here
actually could do the wrong thing for non-NFS filesystems if it
starts more writeback.
nr_unstable is not going to be set for non-NFS filesystems. 'unstable'
is a caching state in which pages have been written out to the NFS
server, but the server has not yet flushed the data to disk.
But if you have NFS and non-NFS filesystems, wakeup_pdflush isn't
always going to do the right thing.
...and most important of all: 'unstable' does _not_ mean that I/O is
active on those pages (unlike the apparent assumption in
vm_throttle_write.
That is why the choice is either to kick pdflush there, or to remove
nr_unstable from the accounting in that loop.
Doesn't matter if IO is actually active or not, if you've allocated
memory for these unstable pages, then page reclaim can scan itself
to death, which is what seems to have happened here. And which is
what vm_throttle_write is supposed to help.
--
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]
