linux-ext4 - Re: [PATCH v3 4/4] ext4: perform dax

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Message-ID: <20170831082427.GE7897@quack2.suse.cz>
Date:   Thu, 31 Aug 2017 10:24:27 +0200
From:   Jan Kara <jack@...e.cz>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     linux-xfs@...r.kernel.org, linux-ext4@...r.kernel.org,
        Jan Kara <jack@...e.cz>, linux-nvdimm@...ts.01.org,
        Andreas Dilger <adilger.kernel@...ger.ca>,
        Theodore Ts'o <tytso@....edu>, Christoph Hellwig <hch@....de>
Subject: Re: [PATCH v3 4/4] ext4: perform dax_device lookup at mount

On Wed 30-08-17 12:44:08, Dan Williams wrote:
> The ->iomap_begin() operation is a hot path, so cache the
> fs_dax_get_by_host() result at mount time to avoid the incurring the
> hash lookup overhead on a per-i/o basis.
> 
> Cc: "Theodore Ts'o" <tytso@....edu>
> Cc: Andreas Dilger <adilger.kernel@...ger.ca>
> Cc: Jan Kara <jack@...e.cz>
> Reported-by: Christoph Hellwig <hch@....de>
> Signed-off-by: Dan Williams <dan.j.williams@...el.com>

Looks good to me. You can add:

Reviewed-by: Jan Kara <jack@...e.cz>

With the same nit as for ext2:

> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index d61a70e2193a..0b3d94e25efb 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -864,6 +864,7 @@ static inline void ext4_quota_off_umount(struct super_block *sb)
>  static void ext4_put_super(struct super_block *sb)
>  {
>  	struct ext4_sb_info *sbi = EXT4_SB(sb);
> +	struct dax_device *dax_dev = sbi->s_daxdev;
>  	struct ext4_super_block *es = sbi->s_es;
>  	int aborted = 0;
>  	int i, err;
> @@ -952,6 +953,7 @@ static void ext4_put_super(struct super_block *sb)
>  		crypto_free_shash(sbi->s_chksum_driver);
>  	kfree(sbi->s_blockgroup_lock);
>  	kfree(sbi);
> +	fs_put_dax(dax_dev);

Just remove dax_dev local variable...

								Honza

-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR