linux-kernel - Re: [PATCH v2 3/4] fat: mark superblock as dirty less often

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Date:	Sat, 14 Apr 2012 18:17:32 +0900
From:	OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
To:	Artem Bityutskiy <dedekind1@...il.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Linux Kernel Maling List <linux-kernel@...r.kernel.org>,
	Linux FS Maling List <linux-fsdevel@...r.kernel.org>,
	Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
Subject: Re: [PATCH v2 3/4] fat: mark superblock as dirty less often

Artem Bityutskiy <dedekind1@...il.com> writes:

> From: Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>
>
> This patch is a preparation for further changes. It touches few functions
> in fatent.c and prevents them from marking the superblock as dirty
> unnecessarily often. Namely, instead of marking it as dirty in the internal
> tight loops - do it only once at the end of the functions. And instead of
> marking it as dirty while holding the FAT table lock, do it outside the lock.
>
> The reason for this patch is that marking the superblock as dirty will soon
> become a little bit heavier operation, so it is cleaner to do this only when it
> is necessary.

For it, please use local variable like,


{
       	int fsinfo_dirty = 0;

	while (1) {
        	change free_clusters
                fsinfo_dirty = 1;
        }

        if (fsinfo_dirty)
        	mark_fsinfo_dirty()
}

instead of dirty it always.
-- 
OGAWA Hirofumi <hirofumi@...l.parknet.co.jp>
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