Messages in this thread | | | Date | Tue, 17 Apr 2007 22:14:02 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [PATCH 0/4] 2.6.21-rc7 NFS writes: fix a series of issues |
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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.
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