linux-kernel - RE: [f2fs-dev] [PATCH 2/2] f2fs: shrink unreferenced extent

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 2 Jul 2015 20:39:43 +0800
From:	Chao Yu <yuchaochina@...mail.com>
To:	"'Jaegeuk Kim'" <jaegeuk@...nel.org>
CC:	<linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>,
	<linux-f2fs-devel@...ts.sourceforge.net>
Subject: RE: [f2fs-dev] [PATCH 2/2] f2fs: shrink unreferenced extent_caches first

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@...nel.org]
> Sent: Wednesday, July 01, 2015 9:26 AM
> To: linux-kernel@...r.kernel.org; linux-fsdevel@...r.kernel.org;
> linux-f2fs-devel@...ts.sourceforge.net; linux-kernel@...r.kernel.org;
> linux-fsdevel@...r.kernel.org; linux-f2fs-devel@...ts.sourceforge.net
> Cc: Jaegeuk Kim; Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 2/2] f2fs: shrink unreferenced extent_caches first
> 
> If an extent_tree entry has a zero reference count, we can drop it from the
> cache in higher priority rather than currently referencing entries.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> ---
>  fs/f2fs/data.c | 51 +++++++++++++++++++++++++++++++++++++++++----------
>  1 file changed, 41 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index 8f059e0..a0a0e2b 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -661,21 +661,54 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int
> nr_shrink)
>  	struct radix_tree_root *root = &sbi->extent_tree_root;
>  	unsigned int found;
>  	unsigned int node_cnt = 0, tree_cnt = 0;
> +	int remained;
> 
>  	if (!test_opt(sbi, EXTENT_CACHE))
>  		return 0;
> 
> +	if (!down_write_trylock(&sbi->extent_tree_lock))
> +		goto out;
> +
> +	/* 1. remove unreferenced extent tree */

We always release extent node and tree from inode with lowest ino,
why not random ino?

And this step releasing breaks the rule of lru runs.

Some unreferenced file has high hit ratio and some referenced file may
have low hit ratio. Why not release low hit ratio extent tree at first?

Thanks,

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/