Re: [PATCH] xfs: do not pass unused params to xfs_flush_pages

From: Eric Sandeen
Date: Tue Apr 22 2008 - 08:51:53 EST


Denys Vlasenko wrote:
> On Tuesday 22 April 2008 05:15, Eric Sandeen wrote:


>>> Compile-tested only.
>> FWIW this one actually does not seem to reduce stack usage anywhere.
>
> I hope this will not deteriorate into a contest whether
> every particular patch reduces stack usage or not, but:

Sorry if you took it that way; since the patch was in response to Dave's
mention of accepting stack-reducing patches, I thought it was worth
checking and highlighting whether it seemed to help. It wasn't supposed
to be an attack or argument.

> You do not see reduced stack usage in "make checkstack",
> because "make checkstack" shows only stack usage caused by
> local variables (it analyses sub %esp,NN instructions which
> make room for them). Parameters also take up stack, but
> they are pushed on stack with push instruction,
> and so are invisible in "make checkstack" output.

Hm, I had assumed that the %esp subtraction also made room for the
arguments pushed onto the stack. Is there no way to analyze that part?

Thanks,
-Eric
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