lkml.org 
[lkml]   [2007]   [Apr]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 0/4] 2.6.21-rc7 NFS writes: fix a series of issues


On Tue, 17 Apr 2007, Florin Iucha wrote:
>
> Already did. Traces from vanilla kernel at
> http://iucha.net/nfs/21-rc7/big-copy

Well, there's a pdflush in io_schedule_timeout/congestion_wait, and
there's a nfsv4-scv in svc_recv/nfs_callback_sv, and a lot of processes
either just in schedule_timeout or similar "normal" waiting (pollwait
etc).

[ The call traces could be prettier, but sadly, even if you enable frame
pointers, the x86-64 kernel is too stupid to follow them. So you kind of
just have to ignore the noise) ]

The triggering process looks like it might be that "cp", it is in the
__wait_on_bit/sync_page/wait_on_page_bit/wait_on_page_writeback_range/
filemap_fdatawait.

Is this a trace from the "big copy" hang, or from a gnome splashscreen
hang? It *looks* like it's a big copy. Yes/no?

Anyway, looks like the cp did a "utimes()" system call, which triggers
"nfs_setattr(), which in turn triggers the filemap_fdatawait() and some
kind of endless wait. Nothing stands out from the traces, in other words.
Doesn't look like a locking thing, for example - we're not stuck on some
inode semaphore, we're literally waiting for the page to be written out.

Linus
-
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: 2007-04-18 07:19    [W:0.421 / U:0.384 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site