linux-kernel - RE: [PATCH v3] exfat: speed up iterate/lookup by fixing start point of traversing cluster chain

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Date:   Tue, 23 Mar 2021 17:26:26 +0900
From:   "Namjae Jeon" <namjae.jeon@...sung.com>
To:     "'Sungjong Seo'" <sj1557.seo@...sung.com>,
        "'Hyeongseok Kim'" <hyeongseok@...il.com>
Cc:     <linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>
Subject: RE: [PATCH v3] exfat: speed up iterate/lookup by fixing start point
 of traversing cluster chain

> > When directory iterate and lookup is called, there's a buggy rewinding
> > of start point for traversing cluster chain to the parent directory
> > entry's first cluster. This caused repeated cluster chain traversing
> > from the first entry of the parent directory that would show worse
> > performance if huge amounts of files exist under the parent directory.
> > Fix not to rewind, make continue from currently referenced cluster and
> > dir entry.
> >
> > Tested with 50,000 files under single directory / 256GB sdcard, with
> > command "time ls -l > /dev/null",
> > Before :     0m08.69s real     0m00.27s user     0m05.91s system
> > After  :     0m07.01s real     0m00.25s user     0m04.34s system
> >
> > Signed-off-by: Hyeongseok Kim <hyeongseok@...il.com>
> 
> Looks good.
> Thanks for your contribution.
> 
> Reviewed-by: Sungjong Seo <sj1557.seo@...sung.com>
Applied. Thanks!