[lkml]   [2007]   [Sep]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: patch: improve generic_file_buffered_write() (2nd try 1/2)
Nick Piggin <> writes:

> Anyway, there are fixes for this deadlock in Andrew's -mm tree, but
> also a workaround for the NFSD problem in git commit 29dbb3fc. Did
> you try a later kernel to see if it is fixed there?

I had a chance to look up that commit (git clone took a while so sorry
for writing 2 mails). It is present in 2.6.23-rc5 so I already noticed
it when merging our patch in 2.6.23-rc5.

Upon closer reading of the patch though I see that it will indeed
prevent writes by the nfsd to be split smaller than PAGE_SIZE and it
will cause filemap_copy_from_user[_iovec] to be called with a source
spanning multiple pages.

So the commit 29dbb3fc should have a simmilar, slightly better even,
gain for the nfsd and other kernel space segments. But it will not
improve writes from user space, where ~14% of the commits were saved
during a days work for me.

Now I have a question about fault_in_pages_readable(). Can I call that
for multiple pages and then call __grab_cache_page() without risking
one of the pages from getting lost again and causing a deadlock?

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-09-07 23:03    [W:0.064 / U:66.300 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site