Re: [PATCH v2 3/4] mm/truncate: bail out early from invalidate_inode_pages2_range() if mapping is empty

From: Jan Kara <jack@suse.cz>
To: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Jan Kara <jack@suse.cz>, Jens Axboe <axboe@kernel.dk>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Alexey Kuznetsov <kuznet@virtuozzo.com>,
	Christoph Hellwig <hch@lst.de>,
	Nikolay Borisov <n.borisov.lkml@gmail.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org
Subject: Re: [PATCH v2 3/4] mm/truncate: bail out early from invalidate_inode_pages2_range() if mapping is empty
Date: Tue, 25 Apr 2017 10:37:15 +0200	[thread overview]
Message-ID: <20170425083715.GD2793@quack2.suse.cz> (raw)
In-Reply-To: <20170424164135.22350-4-aryabinin@virtuozzo.com>

On Mon 24-04-17 19:41:34, Andrey Ryabinin wrote:
> If mapping is empty (both ->nrpages and ->nrexceptional is zero) we can
> avoid pointless lookups in empty radix tree and bail out immediately after
> cleancache invalidation.
> 
> Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
> Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Looks good. You can add:

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

								Honza

> ---
>  mm/truncate.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/mm/truncate.c b/mm/truncate.c
> index 6263aff..8f12b0e 100644
> --- a/mm/truncate.c
> +++ b/mm/truncate.c
> @@ -624,6 +624,9 @@ int invalidate_inode_pages2_range(struct address_space *mapping,
>  	int did_range_unmap = 0;
>  
>  	cleancache_invalidate_inode(mapping);
> +	if (mapping->nrpages == 0 && mapping->nrexceptional == 0)
> +		return 0;
> +
>  	pagevec_init(&pvec, 0);
>  	index = start;
>  	while (index <= end && pagevec_lookup_entries(&pvec, mapping, index,
> -- 
> 2.10.2
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR