From: shenghui <crosslonelyover@gmail.com>
Subject: Re: [PATCH] fix return value for mb_cache_shrink_fn when nr_to_scan >
	0
Date: Tue, 20 Jul 2010 09:04:46 +0800
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Cc: Christoph Hellwig <hch@infradead.org>,
	Eric Sandeen <sandeen@redhat.com>,
	linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk,
	linux-mm@kvack.org, linux-ext4 <linux-ext4@vger.kernel.org>,
	kernel-janitors <kernel-janitors@vger.kernel.org>
To: Andreas Gruenbacher <agruen@suse.de>
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2010/7/20 shenghui <crosslonelyover@gmail.com>:
> 2010/7/20 Andreas Gruenbacher <agruen@suse.de>:
>
> Sorry, I haven't found any special attention on
> sysctl_vfs_cache_pressure =3D=3D 0 case or scale
> nr_to_scan in fs/dcache.c
>
> =C2=A0900static int shrink_dcache_memory(int nr, gfp_t gfp_mask)
> =C2=A0901{
> =C2=A0902 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (nr) {
> =C2=A0903 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0if (=
!(gfp_mask & __GFP_FS))
> =C2=A0904 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=
=A0 =C2=A0 =C2=A0 =C2=A0return -1;
> =C2=A0905 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0prun=
e_dcache(nr);
> =C2=A0906 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
> =C2=A0907 =C2=A0 =C2=A0 =C2=A0 =C2=A0return (dentry_stat.nr_unused / =
100) * sysctl_vfs_cache_pressure;
> =C2=A0908}
>

And for sysctl_vfs_cache_pressure =3D=3D 0 case, it's
enough to return 0 to indicate no cache entries left.



--=20


Thanks and Best Regards,
shenghui
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