Re: [patch] mmap<->write deadlock fix, plus bug in block_write_zero_range

[Chuck Lever <cel@monkey.org>]

On Wed, 22 Dec 1999, Benjamin C.R. LaHaise wrote:
> The patch to filemap.c changes filemap_nopage to use __find_page_nolock
> rather than __find_get_page which waits for the page to become unlocked
> before returning (maybe __find_get_page was meant to check PageUptodate?),
> since filemap_nopage checks PageUptodate before proceeding -- which is
> consistent with do_generic_file_read.

i've tried this before several times.  i could never get the system to
perform as well under benchmark load using find_page_nolock as when using
find_get_page. the throughput difference was about 5%, if i recall.  i
haven't explained this to myself yet.

perhaps a better fix would be to take out some of the page lock complexity
from filemap_nopage?  dunno.

	- Chuck Lever
--
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personal:	<chucklever@netscape.net> or <cel@monkey.org>

The Linux Scalability project:
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