Yum Rayan <[EMAIL PROTECTED]> writes:
> Attempt to reduce stack usage in acct.c (linux-2.6.12-rc1-mm3). Stack
> usage was noted using checkstack.pl. Specifically:
>
> Before patch
> ------------
> check_free_space - 128
>
> After patch
> -----------
> check_free_space - 36
>
> Signed-off-by: Yum Rayan <[EMAIL PROTECTED]>
>
> --- a/kernel/acct.c 2005-03-25 22:11:06.000000000 -0800
> +++ b/kernel/acct.c 2005-03-30 15:33:05.000000000 -0800
> @@ -103,30 +103,32 @@
> */
> static int check_free_space(struct file *file)
> {
> - struct kstatfs sbuf;
> - int res;
> - int act;
> - sector_t resume;
> - sector_t suspend;
> + struct kstatfs *sbuf = NULL;
> + int res, act;
> + sector_t resume, suspend;
I can't see how you expect to save 128-36=92 bytes here. You replace
sizeof(struct kstatfs)=64 with sizeof(struct kstatfs*)=4, which would
be a saving of 60 bytes. But the call to kmalloc()/kfree() reduces
your stack saving further, not to mention the runtime penalty,
introduced by allocating dynamic memory.
Regards, Olaf.
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