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From: Andrea Arcangeli <aarcange@redhat.com>
To: Eric B Munson <emunson@mgebm.net>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Michael J Wolf <mjwolf@us.ibm.com>
Subject: Re: [PATCH 0/5] fix up /proc/$pid/smaps to not split huge pages
Date: Tue, 15 Feb 2011 18:01:52 +0100	[thread overview]
Message-ID: <20110215170152.GF5935@random.random> (raw)
In-Reply-To: <20110215165510.GA2550@mgebm.net>

On Tue, Feb 15, 2011 at 11:55:10AM -0500, Eric B Munson wrote:
> I am noticing in smaps that KernelPageSize is wrong of areas
> that have been merged into THP.  For instance:
> 
> 7ff852a00000-7ff852c00000 rw-p 00000000 00:00 0 
> Size:               2048 kB
> Rss:                2048 kB
> Pss:                2048 kB
> Shared_Clean:          0 kB
> Shared_Dirty:          0 kB
> Private_Clean:         0 kB
> Private_Dirty:      2048 kB
> Referenced:         2048 kB
> Anonymous:          2048 kB
> AnonHugePages:      2048 kB
> Swap:                  0 kB
> KernelPageSize:        4 kB
> MMUPageSize:           4 kB
> Locked:                0 kB
> 
> The entire mapping is contained in a THP but the
> KernelPageSize shows 4kb.  For cases where the mapping might
> have mixed page sizes this may be okay, but for this
> particular mapping the 4kb page size is wrong.

I'm not sure this is a bug, if the mapping grows it may become 4096k
but the new pages may be 4k. There's no such thing as a
vma_mmu_pagesize in terms of hugepages because we support graceful
fallback and collapse/split on the fly without altering the vma. So I
think 4k is correct here.


WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.com>
To: Eric B Munson <emunson@mgebm.net>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Michael J Wolf <mjwolf@us.ibm.com>
Subject: Re: [PATCH 0/5] fix up /proc/$pid/smaps to not split huge pages
Date: Tue, 15 Feb 2011 18:01:52 +0100	[thread overview]
Message-ID: <20110215170152.GF5935@random.random> (raw)
In-Reply-To: <20110215165510.GA2550@mgebm.net>

On Tue, Feb 15, 2011 at 11:55:10AM -0500, Eric B Munson wrote:
> I am noticing in smaps that KernelPageSize is wrong of areas
> that have been merged into THP.  For instance:
> 
> 7ff852a00000-7ff852c00000 rw-p 00000000 00:00 0 
> Size:               2048 kB
> Rss:                2048 kB
> Pss:                2048 kB
> Shared_Clean:          0 kB
> Shared_Dirty:          0 kB
> Private_Clean:         0 kB
> Private_Dirty:      2048 kB
> Referenced:         2048 kB
> Anonymous:          2048 kB
> AnonHugePages:      2048 kB
> Swap:                  0 kB
> KernelPageSize:        4 kB
> MMUPageSize:           4 kB
> Locked:                0 kB
> 
> The entire mapping is contained in a THP but the
> KernelPageSize shows 4kb.  For cases where the mapping might
> have mixed page sizes this may be okay, but for this
> particular mapping the 4kb page size is wrong.

I'm not sure this is a bug, if the mapping grows it may become 4096k
but the new pages may be 4k. There's no such thing as a
vma_mmu_pagesize in terms of hugepages because we support graceful
fallback and collapse/split on the fly without altering the vma. So I
think 4k is correct here.

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  reply	other threads:[~2011-02-15 17:02 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-02-09 19:54 [PATCH 0/5] fix up /proc/$pid/smaps to not split huge pages Dave Hansen
2011-02-09 19:54 ` Dave Hansen
2011-02-09 19:54 ` [PATCH 1/5] pagewalk: only split huge pages when necessary Dave Hansen
2011-02-09 19:54   ` Dave Hansen
2011-02-10 11:11   ` Mel Gorman
2011-02-10 11:11     ` Mel Gorman
2011-02-10 13:19     ` Andrea Arcangeli
2011-02-10 13:19       ` Andrea Arcangeli
2011-02-10 13:34       ` Mel Gorman
2011-02-10 13:34         ` Mel Gorman
2011-02-09 19:54 ` [PATCH 2/5] break out smaps_pte_entry() from smaps_pte_range() Dave Hansen
2011-02-09 19:54   ` Dave Hansen
2011-02-10 11:15   ` Mel Gorman
2011-02-10 11:15     ` Mel Gorman
2011-02-09 19:54 ` [PATCH 3/5] pass pte size argument in to smaps_pte_entry() Dave Hansen
2011-02-09 19:54   ` Dave Hansen
2011-02-10 11:16   ` Mel Gorman
2011-02-10 11:16     ` Mel Gorman
2011-02-09 19:54 ` [PATCH 4/5] teach smaps_pte_range() about THP pmds Dave Hansen
2011-02-09 19:54   ` Dave Hansen
2011-02-10 11:17   ` Mel Gorman
2011-02-10 11:17     ` Mel Gorman
2011-02-10 18:08   ` Andrea Arcangeli
2011-02-10 18:08     ` Andrea Arcangeli
2011-02-10 19:32     ` Dave Hansen
2011-02-10 19:32       ` Dave Hansen
2011-02-09 19:54 ` [PATCH 5/5] have smaps show transparent huge pages Dave Hansen
2011-02-09 19:54   ` Dave Hansen
2011-02-10 11:20   ` Mel Gorman
2011-02-10 11:20     ` Mel Gorman
2011-02-10 15:01     ` Dave Hansen
2011-02-10 15:01       ` Dave Hansen
2011-02-10 15:09       ` Mel Gorman
2011-02-10 15:09         ` Mel Gorman
2011-02-10 18:09         ` Andrea Arcangeli
2011-02-10 18:09           ` Andrea Arcangeli
2011-02-10 18:20           ` Dave Hansen
2011-02-10 18:20             ` Dave Hansen
2011-02-10 18:39             ` Andrea Arcangeli
2011-02-10 18:39               ` Andrea Arcangeli
2011-02-09 21:24 ` [PATCH 0/5] fix up /proc/$pid/smaps to not split " Andrea Arcangeli
2011-02-09 21:24   ` Andrea Arcangeli
2011-02-20 21:54   ` David Rientjes
2011-02-20 21:54     ` David Rientjes
2011-02-15 16:55 ` Eric B Munson
2011-02-15 17:01   ` Andrea Arcangeli [this message]
2011-02-15 17:01     ` Andrea Arcangeli
2011-02-15 17:05     ` Dave Hansen
2011-02-15 17:05       ` Dave Hansen
2011-02-15 18:00       ` Andrea Arcangeli
2011-02-15 18:00         ` Andrea Arcangeli
2011-02-22  1:53 Dave Hansen
2011-02-22  1:53 ` Dave Hansen

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