Messages in this thread | | | Date | Mon, 28 Apr 2008 09:23:17 +1000 | From | David Chinner <> | Subject | Re: [PATCH] xfs: reduce stack usage in xfs_page_state_convert() |
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On Sun, Apr 27, 2008 at 02:46:58AM +0200, Denys Vlasenko wrote: > Hi David, > > This patch reduces xfs_page_state_convert() stack usage by 16 bytes > by eliminating some local variables, and reducing the size > of scope for other locals. > > Compile tested only.
Can you start testing your patches? if you are touching the writeback or allocator path, there's a pretty high barrier to having patches excepted, and testing them before is one of them. Go and download the XFSQA suite from the xfs-cmds CVS tree on oss.sgi.com, and run your patches through it....
> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> > > P.S. > > xfs_page_state_convert() carries the following comment: > * Calling this without startio set means we are being asked to make a dirty > * page ready for freeing it's buffers. When called with startio set then > * we are coming from writepage. > which leads to the following proposal: reimplement it as two > functions, one which work as if startio parameter == 0 > and the other as if startio == 1. > This will result in a bit of code duplication, but reduces > stack usage on writepage path and allows for these two functions > to have more descriptive names. (Presently the meaning of this > function needs to be explained in that comment -> function > name is not descriptive enough, because it does different things > depending on startio value). > > Do you like this idea?
No. That code is complex enough with only one copy of it around. I don't want two copies that differ subtly and hence have two different sets of nasty, rarely hit corner cases in them.
Cheers,
Dave. -- Dave Chinner Principal Engineer SGI Australian Software Group
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