Linux-kernel mailing list archive 1999-32,: Re: [PATCH] ext2/namei.c lookup performance patch

# Re: [PATCH] ext2/namei.c lookup performance patch

Sang-yong Suh (sysuh@kigam.re.kr)
Wed, 11 Aug 1999 10:20:20 +0900

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On Tue, Aug 10, 1999 at 11:46:56AM -0400, Alexander Viro <viro@math.psu.edu> wrote:
> Beautiful. Just to clarify: proposed patch drops the cached offset in the
> rename(), so it's OK in that area.

Thank you for the applaude. Actually, it was my very first result of
Linux kernel hack...

> I have a couple of small fixes (e.g. foo[++bar]==baz[bar] is *not* a valid
> C - order of evaluation is not guaranteed here), but the thing looks

Oops! I didn't aware of that. The reason I changed ext2_match() was
for my news server, where almost all files have same leading characters,
as:
news:~/spool/articles/control/cancel$ ls -1 | tail -10
32942461
32942462
32942463
32942464
32942465
32942466
32942467
32942468
32942469
32942470

Therefore, for news servers, checking the last character first should
be a great win. Anyway, please correct my error and clean up my patch
as well.

> Would you mind if I'll merge it with another kind of lookup
> caching (if the directory didn't change since the last real lookup - start
> searching from that position; it helps if we are going to do a sequence of
> ->lookup() after the readdir(), e.g. in any shell globbing, etc.)?

I will certainly appreciate a lot if you do that. Your caching should
be more effective for the general puropse users.

Regards,

    --
    Sang-yong Suh

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