From: Seth Jennings <sjenning@linux.vnet.ibm.com>
To: Dave Hansen <dave@sr71.net>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, mgorman@suse.de,
tim.c.chen@linux.intel.com
Subject: Re: [RFCv2][PATCH 0/5] mm: Batch page reclamation under shink_page_list
Date: Mon, 20 May 2013 16:55:42 -0500 [thread overview]
Message-ID: <20130520215542.GC25536@cerebellum> (raw)
In-Reply-To: <20130516203427.E3386936@viggo.jf.intel.com>
On Thu, May 16, 2013 at 01:34:27PM -0700, Dave Hansen wrote:
> These are an update of Tim Chen's earlier work:
>
> http://lkml.kernel.org/r/1347293960.9977.70.camel@schen9-DESK
>
> I broke the patches up a bit more, and tried to incorporate some
> changes based on some feedback from Mel and Andrew.
>
> Changes for v2:
> * use page_mapping() accessor instead of direct access
> to page->mapping (could cause crashes when running in
> to swap cache pages.
> * group the batch function's introduction patch with
> its first use
> * rename a few functions as suggested by Mel
> * Ran some single-threaded tests to look for regressions
> caused by the batching. If there is overhead, it is only
> in the worst-case scenarios, and then only in hundreths of
> a percent of CPU time.
>
> If you're curious how effective the batching is, I have a quick
> and dirty patch to keep some stats:
>
> https://www.sr71.net/~dave/intel/rmb-stats-only.patch
>
Didn't do any performance comparison but did a kernel build with 2 make threads
per core in a memory constrained situation w/ zswap add got an average batch
size of 6.6 pages with the batch being empty on ~10% of calls.
rmb call: 423464
rmb pages: 2790332
rmb empty: 41408
The WARN_ONCE only gave me one stack for the first empty batch and, for what
it's worth, it was from kswapd.
Tested-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
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WARNING: multiple messages have this Message-ID (diff)
From: Seth Jennings <sjenning@linux.vnet.ibm.com>
To: Dave Hansen <dave@sr71.net>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, mgorman@suse.de,
tim.c.chen@linux.intel.com
Subject: Re: [RFCv2][PATCH 0/5] mm: Batch page reclamation under shink_page_list
Date: Mon, 20 May 2013 16:55:42 -0500 [thread overview]
Message-ID: <20130520215542.GC25536@cerebellum> (raw)
In-Reply-To: <20130516203427.E3386936@viggo.jf.intel.com>
On Thu, May 16, 2013 at 01:34:27PM -0700, Dave Hansen wrote:
> These are an update of Tim Chen's earlier work:
>
> http://lkml.kernel.org/r/1347293960.9977.70.camel@schen9-DESK
>
> I broke the patches up a bit more, and tried to incorporate some
> changes based on some feedback from Mel and Andrew.
>
> Changes for v2:
> * use page_mapping() accessor instead of direct access
> to page->mapping (could cause crashes when running in
> to swap cache pages.
> * group the batch function's introduction patch with
> its first use
> * rename a few functions as suggested by Mel
> * Ran some single-threaded tests to look for regressions
> caused by the batching. If there is overhead, it is only
> in the worst-case scenarios, and then only in hundreths of
> a percent of CPU time.
>
> If you're curious how effective the batching is, I have a quick
> and dirty patch to keep some stats:
>
> https://www.sr71.net/~dave/intel/rmb-stats-only.patch
>
Didn't do any performance comparison but did a kernel build with 2 make threads
per core in a memory constrained situation w/ zswap add got an average batch
size of 6.6 pages with the batch being empty on ~10% of calls.
rmb call: 423464
rmb pages: 2790332
rmb empty: 41408
The WARN_ONCE only gave me one stack for the first empty batch and, for what
it's worth, it was from kswapd.
Tested-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
next prev parent reply other threads:[~2013-05-20 21:55 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-16 20:34 [RFCv2][PATCH 0/5] mm: Batch page reclamation under shink_page_list Dave Hansen
2013-05-16 20:34 ` Dave Hansen
2013-05-16 20:34 ` [RFCv2][PATCH 1/5] defer clearing of page_private() for swap cache pages Dave Hansen
2013-05-16 20:34 ` Dave Hansen
2013-05-16 20:34 ` [RFCv2][PATCH 2/5] make 'struct page' and swp_entry_t variants of swapcache_free() Dave Hansen
2013-05-16 20:34 ` Dave Hansen
2013-05-17 13:27 ` Mel Gorman
2013-05-17 13:27 ` Mel Gorman
2013-05-16 20:34 ` [RFCv2][PATCH 3/5] break up __remove_mapping() Dave Hansen
2013-05-16 20:34 ` Dave Hansen
2013-05-16 20:34 ` [RFCv2][PATCH 4/5] break out mapping "freepage" code Dave Hansen
2013-05-16 20:34 ` Dave Hansen
2013-05-16 20:34 ` [RFCv2][PATCH 5/5] batch shrink_page_list() locking operations Dave Hansen
2013-05-16 20:34 ` Dave Hansen
2013-05-17 13:35 ` Mel Gorman
2013-05-17 13:35 ` Mel Gorman
2013-05-20 21:55 ` Seth Jennings [this message]
2013-05-20 21:55 ` [RFCv2][PATCH 0/5] mm: Batch page reclamation under shink_page_list Seth Jennings
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