From: David Rientjes <rientjes@google.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Michael J Wolf <mjwolf@us.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>
Subject: Re: [PATCH 1/5] pagewalk: only split huge pages when necessary
Date: Tue, 22 Feb 2011 13:21:48 -0800 (PST) [thread overview]
Message-ID: <alpine.DEB.2.00.1102221316400.5929@chino.kir.corp.google.com> (raw)
In-Reply-To: <20110222015339.0C9A2212@kernel>
On Mon, 21 Feb 2011, Dave Hansen wrote:
>
> v2 - rework if() block, and remove now redundant split_huge_page()
>
> Right now, if a mm_walk has either ->pte_entry or ->pmd_entry
> set, it will unconditionally split any transparent huge pages
> it runs in to. In practice, that means that anyone doing a
>
> cat /proc/$pid/smaps
>
> will unconditionally break down every huge page in the process
> and depend on khugepaged to re-collapse it later. This is
> fairly suboptimal.
>
> This patch changes that behavior. It teaches each ->pmd_entry
> handler (there are five) that they must break down the THPs
> themselves. Also, the _generic_ code will never break down
> a THP unless a ->pte_entry handler is actually set.
>
> This means that the ->pmd_entry handlers can now choose to
> deal with THPs without breaking them down.
>
> Acked-by: Mel Gorman <mel@csn.ul.ie>
> Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Thanks for adding the comment about ->pmd_entry() being required to split
the pages in include/linux/mm.h!
WARNING: multiple messages have this Message-ID (diff)
From: David Rientjes <rientjes@google.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Michael J Wolf <mjwolf@us.ibm.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>
Subject: Re: [PATCH 1/5] pagewalk: only split huge pages when necessary
Date: Tue, 22 Feb 2011 13:21:48 -0800 (PST) [thread overview]
Message-ID: <alpine.DEB.2.00.1102221316400.5929@chino.kir.corp.google.com> (raw)
In-Reply-To: <20110222015339.0C9A2212@kernel>
On Mon, 21 Feb 2011, Dave Hansen wrote:
>
> v2 - rework if() block, and remove now redundant split_huge_page()
>
> Right now, if a mm_walk has either ->pte_entry or ->pmd_entry
> set, it will unconditionally split any transparent huge pages
> it runs in to. In practice, that means that anyone doing a
>
> cat /proc/$pid/smaps
>
> will unconditionally break down every huge page in the process
> and depend on khugepaged to re-collapse it later. This is
> fairly suboptimal.
>
> This patch changes that behavior. It teaches each ->pmd_entry
> handler (there are five) that they must break down the THPs
> themselves. Also, the _generic_ code will never break down
> a THP unless a ->pte_entry handler is actually set.
>
> This means that the ->pmd_entry handlers can now choose to
> deal with THPs without breaking them down.
>
> Acked-by: Mel Gorman <mel@csn.ul.ie>
> Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Thanks for adding the comment about ->pmd_entry() being required to split
the pages in include/linux/mm.h!
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next prev parent reply other threads:[~2011-02-22 21:21 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-22 1:53 [PATCH 0/5] fix up /proc/$pid/smaps to not split huge pages Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-22 1:53 ` [PATCH 1/5] pagewalk: only split huge pages when necessary Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-22 21:21 ` David Rientjes [this message]
2011-02-22 21:21 ` David Rientjes
2011-02-23 15:30 ` Eric B Munson
2011-02-22 1:53 ` [PATCH 2/5] break out smaps_pte_entry() from smaps_pte_range() Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-22 21:21 ` David Rientjes
2011-02-22 21:21 ` David Rientjes
2011-02-23 15:30 ` Eric B Munson
2011-02-22 1:53 ` [PATCH 3/5] pass pte size argument in to smaps_pte_entry() Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-22 21:21 ` David Rientjes
2011-02-22 21:21 ` David Rientjes
2011-02-23 15:30 ` Eric B Munson
2011-02-22 1:53 ` [PATCH 4/5] teach smaps_pte_range() about THP pmds Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-22 13:35 ` Andrea Arcangeli
2011-02-22 13:35 ` Andrea Arcangeli
2011-02-22 21:22 ` David Rientjes
2011-02-22 21:22 ` David Rientjes
2011-02-23 15:31 ` Eric B Munson
2011-02-22 1:53 ` [PATCH 5/5] have smaps show transparent huge pages Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-23 15:31 ` Eric B Munson
-- strict thread matches above, loose matches on Subject: below --
2011-02-09 19:54 [PATCH 0/5] fix up /proc/$pid/smaps to not split " Dave Hansen
2011-02-09 19:54 ` [PATCH 1/5] pagewalk: only split huge pages when necessary Dave Hansen
2011-02-09 19:54 ` Dave Hansen
2011-02-10 11:11 ` Mel Gorman
2011-02-10 11:11 ` Mel Gorman
2011-02-10 13:19 ` Andrea Arcangeli
2011-02-10 13:19 ` Andrea Arcangeli
2011-02-10 13:34 ` Mel Gorman
2011-02-10 13:34 ` Mel Gorman
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