Re: [PATCH][resend][SCSI] Reduce number of sequential pointerderefs in scsi_error.c and reduce size as well

From: James Bottomley
Date: Tue Dec 21 2010 - 12:38:09 EST


On Sun, 2010-11-21 at 19:48 +0100, Jesper Juhl wrote:
> On Sat, 20 Nov 2010, Linus Torvalds wrote:
>
> > On Sat, Nov 20, 2010 at 12:30 PM, Jesper Juhl <jj@xxxxxxxxxxxxx> wrote:
> > >
> > > Ok, I tried doing that (see patch below)
> >
> > Actually, you kind of chose exactly the reverse of the functions I'd
> > have chosen.
> >
> > Try doing the added parameter to the small static helper functions.
> > Those are the ones that tend to get inlined, and then the parameter
> > should actually result in _fewer_ pointer reloads.
> >
> > So the ones like this:
> >
> > > static int __scsi_try_to_abort_cmd(struct scsi_cmnd *scmd)
> [...]
>
> I see your point now.
>
> I tried this with most of the functions where it seemed that it could
> possibly be a gain, but in the end it turned out that only the one you
> pointed out above actually saw any benefit, so that's the only one I
> changed.
>
> In the end, the object size is down to this:
>
> text data bss dec hex filename
> 18713 128 4704 23545 5bf9 drivers/scsi/scsi_error.o
>
> from this:
>
> text data bss dec hex filename
> 18790 128 4712 23630 5c4e drivers/scsi/scsi_error.o
>
>
> and the patch looks like this now:
>
> Signed-off-by: Jesper Juhl <jj@xxxxxxxxxxxxx>

This is rejecting against scsi-misc:

patching file drivers/scsi/scsi_error.c
Hunk #9 FAILED at 610.
Hunk #10 FAILED at 647.
Hunk #11 succeeded at 850 (offset -22 lines).
Hunk #12 succeeded at 970 (offset -22 lines).
Hunk #13 succeeded at 1013 (offset -22 lines).
Hunk #14 succeeded at 1067 (offset -22 lines).
Hunk #15 succeeded at 1167 (offset -33 lines).
Hunk #16 succeeded at 1184 (offset -33 lines).
Hunk #17 succeeded at 1226 (offset -33 lines).
Hunk #18 succeeded at 1379 (offset -33 lines).
Hunk #19 succeeded at 1976 (offset -33 lines).
2 out of 19 hunks FAILED -- saving rejects to file
drivers/scsi/scsi_error.c.rej

It looks like changes caused by

commit 459dbf72e4d2b4aa13620e6b70d54f098547bf13
[SCSI] Eliminate error handler overload of the SCSI serial number

Could you respin so it applies, please?

Thanks,

James


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