Re: [PATCH] Reduce stack usage in acct.c

From: Randy.Dunlap
Date: Thu Mar 31 2005 - 15:12:32 EST


Jörn Engel wrote:
On Wed, 30 March 2005 23:39:40 -0800, Yum Rayan wrote:

Before patch
------------
check_free_space - 128
do_acct_process - 105

After patch
-----------
check_free_space - 36
do_acct_process - 44


It is always nice to see enthusiams, but in your case it might be a
bit misguided. None of the functions you worked on appear to be real
problems wrt. stack usage.

Yes, this is similar to what I was about to write.
It would be more useful to tackle the really large stack consumers
or ones in deep call chains.

But if you have time to tackle some of these functions, that may make
a real difference:

http://wh.fh-wedel.de/~joern/stackcheck.2.6.11

In principle, all recursive paths should consume as little stack as
possible. Or the recursion itself could be avoided, even better. And
some of the call chains with ~3k of stack consumption may be
problematic on other platforms, like the x86-64. Taking care of those
could result in smaller stacks for the respective platform.

Here is 2.6.12-rc1-bk3 raw checkstack output on x86-64:
http://developer.osdl.org/~rddunlap/doc/checkstack1.out

--
~Randy
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