From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Wed, 11 Oct 2017 08:39:59 +0100
From: Mel Gorman <mgorman@suse.de>
To: Jan Kara <jack@suse.cz>
Cc: linux-mm@kvack.org,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 7/7] mm: Batch radix tree operations when truncating pages
Message-ID: <20171011073959.tvajcejxho7g7zw2@suse.de>
References: <20171010151937.26984-1-jack@suse.cz>
 <20171010151937.26984-8-jack@suse.cz>
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On Tue, Oct 10, 2017 at 05:19:37PM +0200, Jan Kara wrote:
> Currently we remove pages from the radix tree one by one. To speed up
> page cache truncation, lock several pages at once and free them in one
> go. This allows us to batch radix tree operations in a more efficient
> way and also save round-trips on mapping->tree_lock. As a result we gain
> about 20% speed improvement in page cache truncation.
> 
> Data from a simple benchmark timing 10000 truncates of 1024 pages (on
> ext4 on ramdisk but the filesystem is barely visible in the profiles).
> The range shows 1% and 95% percentiles of the measured times:
> 
> 4.14-rc2	4.14-rc2 + batched truncation
> 248-256		209-219
> 249-258		209-217
> 248-255		211-239
> 248-255		209-217
> 247-256		210-218
> 
> Signed-off-by: Jan Kara <jack@suse.cz>

Acked-by: Mel Gorman <mgorman@suse.de>

-- 
Mel Gorman
SUSE Labs

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