From: Jan Kara <jack@suse.cz>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Linux-MM <linux-mm@kvack.org>,
Linux-FSDevel <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>, Jan Kara <jack@suse.cz>,
Andi Kleen <ak@linux.intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Dave Chinner <david@fromorbit.com>
Subject: Re: [PATCH 2/8] mm, truncate: Do not check mapping for every page being truncated
Date: Thu, 12 Oct 2017 14:15:27 +0200 [thread overview]
Message-ID: <20171012121527.GA29293@quack2.suse.cz> (raw)
In-Reply-To: <20171012093103.13412-3-mgorman@techsingularity.net>
On Thu 12-10-17 10:30:57, Mel Gorman wrote:
> During truncation, the mapping has already been checked for shmem and dax
> so it's known that workingset_update_node is required. This patch avoids
> the checks on mapping for each page being truncated. In all other cases,
> a lookup helper is used to determine if workingset_update_node() needs
> to be called. The one danger is that the API is slightly harder to use as
> calling workingset_update_node directly without checking for dax or shmem
> mappings could lead to surprises. However, the API rarely needs to be used
> and hopefully the comment is enough to give people the hint.
>
> sparsetruncate (tiny)
> 4.14.0-rc4 4.14.0-rc4
> oneirq-v1r1 pickhelper-v1r1
> Min Time 141.00 ( 0.00%) 140.00 ( 0.71%)
> 1st-qrtle Time 142.00 ( 0.00%) 141.00 ( 0.70%)
> 2nd-qrtle Time 142.00 ( 0.00%) 142.00 ( 0.00%)
> 3rd-qrtle Time 143.00 ( 0.00%) 143.00 ( 0.00%)
> Max-90% Time 144.00 ( 0.00%) 144.00 ( 0.00%)
> Max-95% Time 147.00 ( 0.00%) 145.00 ( 1.36%)
> Max-99% Time 195.00 ( 0.00%) 191.00 ( 2.05%)
> Max Time 230.00 ( 0.00%) 205.00 ( 10.87%)
> Amean Time 144.37 ( 0.00%) 143.82 ( 0.38%)
> Stddev Time 10.44 ( 0.00%) 9.00 ( 13.74%)
> Coeff Time 7.23 ( 0.00%) 6.26 ( 13.41%)
> Best99%Amean Time 143.72 ( 0.00%) 143.34 ( 0.26%)
> Best95%Amean Time 142.37 ( 0.00%) 142.00 ( 0.26%)
> Best90%Amean Time 142.19 ( 0.00%) 141.85 ( 0.24%)
> Best75%Amean Time 141.92 ( 0.00%) 141.58 ( 0.24%)
> Best50%Amean Time 141.69 ( 0.00%) 141.31 ( 0.27%)
> Best25%Amean Time 141.38 ( 0.00%) 140.97 ( 0.29%)
>
> As you'd expect, the gain is marginal but it can be detected. The differences
> in bonnie are all within the noise which is not surprising given the impact
> on the microbenchmark.
>
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
...
> diff --git a/mm/workingset.c b/mm/workingset.c
> index 7119cd745ace..a80d52387734 100644
> --- a/mm/workingset.c
> +++ b/mm/workingset.c
> @@ -341,12 +341,6 @@ static struct list_lru shadow_nodes;
>
> void workingset_update_node(struct radix_tree_node *node, void *private)
> {
> - struct address_space *mapping = private;
> -
> - /* Only regular page cache has shadow entries */
> - if (dax_mapping(mapping) || shmem_mapping(mapping))
> - return;
> -
Hum, we don't need to pass 'mapping' from call sites then? Either pass NULL
or just remove the argument completely since nobody needs it anymore...
Otherwise the patch looks good.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
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next prev parent reply other threads:[~2017-10-12 12:15 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-12 9:30 [PATCH 0/8] Follow-up for speed up page cache truncation Mel Gorman
2017-10-12 9:30 ` [PATCH 1/8] mm, page_alloc: Enable/disable IRQs once when freeing a list of pages Mel Gorman
2017-10-12 9:30 ` [PATCH 2/8] mm, truncate: Do not check mapping for every page being truncated Mel Gorman
2017-10-12 12:15 ` Jan Kara [this message]
2017-10-12 12:41 ` Mel Gorman
2017-10-12 19:11 ` Johannes Weiner
2017-10-12 9:30 ` [PATCH 3/8] mm, truncate: Remove all exceptional entries from pagevec under one lock Mel Gorman
2017-10-12 13:33 ` Jan Kara
2017-10-12 14:53 ` Mel Gorman
2017-10-12 19:45 ` Johannes Weiner
2017-10-12 9:30 ` [PATCH 4/8] mm: Only drain per-cpu pagevecs once per pagevec usage Mel Gorman
2017-10-12 9:31 ` [PATCH 5/8] mm, pagevec: Remove cold parameter for pagevecs Mel Gorman
2017-10-12 9:31 ` [PATCH 6/8] mm: Remove cold parameter for release_pages Mel Gorman
2017-10-12 9:31 ` [PATCH 7/8] mm, Remove cold parameter from free_hot_cold_page* Mel Gorman
2017-10-12 9:31 ` [PATCH 8/8] mm: Remove __GFP_COLD Mel Gorman
2017-10-18 7:59 [PATCH 0/8] Follow-up for speed up page cache truncation v2 Mel Gorman
2017-10-18 7:59 ` [PATCH 2/8] mm, truncate: Do not check mapping for every page being truncated Mel Gorman
2017-10-19 8:11 ` Jan Kara
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