linux-kernel - Re: [PATCH v2 4/4] mm/truncate: avoid pointless cleancache_invalidate

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Date:   Tue, 25 Apr 2017 10:41:57 +0200
From:   Jan Kara <jack@...e.cz>
To:     Andrey Ryabinin <aryabinin@...tuozzo.com>
Cc:     Alexander Viro <viro@...iv.linux.org.uk>,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        Ross Zwisler <ross.zwisler@...ux.intel.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Jan Kara <jack@...e.cz>, Jens Axboe <axboe@...nel.dk>,
        Johannes Weiner <hannes@...xchg.org>,
        Alexey Kuznetsov <kuznet@...tuozzo.com>,
        Christoph Hellwig <hch@....de>,
        Nikolay Borisov <n.borisov.lkml@...il.com>,
        linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-mm@...ck.org
Subject: Re: [PATCH v2 4/4] mm/truncate: avoid pointless
 cleancache_invalidate_inode() calls.

On Mon 24-04-17 19:41:35, Andrey Ryabinin wrote:
> cleancache_invalidate_inode() called truncate_inode_pages_range()
> and invalidate_inode_pages2_range() twice - on entry and on exit.
> It's stupid and waste of time. It's enough to call it once at
> exit.
> 
> Signed-off-by: Andrey Ryabinin <aryabinin@...tuozzo.com>
> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>

Looks sensible to me but I don't really know cleancache :). Anyway feel
free to add:

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

> ---
>  mm/truncate.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
> 
> diff --git a/mm/truncate.c b/mm/truncate.c
> index 8f12b0e..83a059e 100644
> --- a/mm/truncate.c
> +++ b/mm/truncate.c
> @@ -266,9 +266,8 @@ void truncate_inode_pages_range(struct address_space *mapping,
>  	pgoff_t		index;
>  	int		i;
>  
> -	cleancache_invalidate_inode(mapping);
>  	if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
> -		return;
> +		goto out;
>  
>  	/* Offsets within partial pages */
>  	partial_start = lstart & (PAGE_SIZE - 1);
> @@ -363,7 +362,7 @@ void truncate_inode_pages_range(struct address_space *mapping,
>  	 * will be released, just zeroed, so we can bail out now.
>  	 */
>  	if (start >= end)
> -		return;
> +		goto out;
>  
>  	index = start;
>  	for ( ; ; ) {
> @@ -410,6 +409,8 @@ void truncate_inode_pages_range(struct address_space *mapping,
>  		pagevec_release(&pvec);
>  		index++;
>  	}
> +
> +out:
>  	cleancache_invalidate_inode(mapping);
>  }
>  EXPORT_SYMBOL(truncate_inode_pages_range);
> @@ -623,9 +624,8 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
>  	int ret2 = 0;
>  	int did_range_unmap = 0;
>  
> -	cleancache_invalidate_inode(mapping);
>  	if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
> -		return 0;
> +		goto out;
>  
>  	pagevec_init(&pvec, 0);
>  	index = start;
> @@ -689,6 +689,8 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
>  		cond_resched();
>  		index++;
>  	}
> +
> +out:
>  	cleancache_invalidate_inode(mapping);
>  	return ret;
>  }
> -- 
> 2.10.2
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR