From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: linux-kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: vfat unlink latency 54.6ms for 128MB files
Date: Tue, 11 Jan 2005 03:38:32 +0900 [thread overview]
Message-ID: <878y71xh7b.fsf@devron.myhome.or.jp> (raw)
In-Reply-To: <20050110012330.GA10846@m.safari.iki.fi> (Sami Farin's message of "Mon, 10 Jan 2005 03:23:30 +0200")
Sami Farin <7atbggg02@sneakemail.com> writes:
> Just wondering, when I remove a 128MB file on vfat partition
> (usb-storage, memcard reader), it causes 54.6ms latency
> in rtc_latencytest... latency seems to increase linearly
> as the filesize grows. I calculated 1s would be reached with
> 2344MB file but I didn't bother trying that yet.
> Are there any possible fixes for fat fs so
> that it doesn't disable interrupts for that long a time?
The fatfs itself doesn't disable any interrupt. I guess the thing
depending on file size is the fat_free().
So, the following patch may change the behavior...
--
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
diff -up linux-2.6.10/fs/fat/cache.c.orig linux-2.6.10/fs/fat/cache.c
--- linux-2.6.10/fs/fat/cache.c.orig 2004-12-25 06:35:24.000000000 +0900
+++ linux-2.6.10/fs/fat/cache.c 2005-01-11 03:34:54.000000000 +0900
@@ -491,6 +491,8 @@ int fat_free(struct inode *inode, int sk
if (MSDOS_SB(sb)->free_clusters != -1)
MSDOS_SB(sb)->free_clusters++;
inode->i_blocks -= MSDOS_SB(sb)->cluster_size >> 9;
+
+ cond_resched();
} while (nr != FAT_ENT_EOF);
fat_clusters_flush(sb);
nr = 0;
next prev parent reply other threads:[~2005-01-10 18:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-10 1:23 vfat unlink latency 54.6ms for 128MB files Sami Farin
2005-01-10 18:38 ` OGAWA Hirofumi [this message]
2005-01-10 19:39 ` Sami Farin
2005-01-10 22:36 ` Robert Hardy
2005-01-10 23:41 ` OGAWA Hirofumi
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