From: Andrea Arcangeli <aarcange@redhat.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>,
akpm@osdl.org, Mel Gorman <mel@csn.ul.ie>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 4/5] teach smaps_pte_range() about THP pmds
Date: Tue, 22 Feb 2011 14:35:20 +0100 [thread overview]
Message-ID: <20110222133520.GS13092@random.random> (raw)
In-Reply-To: <20110222015343.41586948@kernel>
On Mon, Feb 21, 2011 at 05:53:43PM -0800, Dave Hansen wrote:
> @@ -385,8 +387,25 @@ static int smaps_pte_range(pmd_t *pmd, u
> pte_t *pte;
> spinlock_t *ptl;
>
> - split_huge_page_pmd(walk->mm, pmd);
> -
> + spin_lock(&walk->mm->page_table_lock);
> + if (pmd_trans_huge(*pmd)) {
> + if (pmd_trans_splitting(*pmd)) {
> + spin_unlock(&walk->mm->page_table_lock);
> + wait_split_huge_page(vma->anon_vma, pmd);
> + } else {
> + smaps_pte_entry(*(pte_t *)pmd, addr,
> + HPAGE_PMD_SIZE, walk);
> + spin_unlock(&walk->mm->page_table_lock);
> + return 0;
> + }
> + } else {
> + spin_unlock(&walk->mm->page_table_lock);
> + }
> + /*
> + * The mmap_sem held all the way back in m_start() is what
> + * keeps khugepaged out of here and from collapsing things
> + * in here.
> + */
This time the locking is right and HPAGE_PMD_SIZE is used instead of
HPAGE_SIZE, thanks! I think all 5 patches can go in -mm and upstream
anytime (not mandatory for 2.6.38 but definitely we want this for
2.6.39).
BTW, Andi in his NUMA THP improvement series added a THP_SPLIT vmstat
per-cpu counter so that part removed from his series, is taken care by
him.
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <aarcange@redhat.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>,
akpm@osdl.org, Mel Gorman <mel@csn.ul.ie>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH 4/5] teach smaps_pte_range() about THP pmds
Date: Tue, 22 Feb 2011 14:35:20 +0100 [thread overview]
Message-ID: <20110222133520.GS13092@random.random> (raw)
In-Reply-To: <20110222015343.41586948@kernel>
On Mon, Feb 21, 2011 at 05:53:43PM -0800, Dave Hansen wrote:
> @@ -385,8 +387,25 @@ static int smaps_pte_range(pmd_t *pmd, u
> pte_t *pte;
> spinlock_t *ptl;
>
> - split_huge_page_pmd(walk->mm, pmd);
> -
> + spin_lock(&walk->mm->page_table_lock);
> + if (pmd_trans_huge(*pmd)) {
> + if (pmd_trans_splitting(*pmd)) {
> + spin_unlock(&walk->mm->page_table_lock);
> + wait_split_huge_page(vma->anon_vma, pmd);
> + } else {
> + smaps_pte_entry(*(pte_t *)pmd, addr,
> + HPAGE_PMD_SIZE, walk);
> + spin_unlock(&walk->mm->page_table_lock);
> + return 0;
> + }
> + } else {
> + spin_unlock(&walk->mm->page_table_lock);
> + }
> + /*
> + * The mmap_sem held all the way back in m_start() is what
> + * keeps khugepaged out of here and from collapsing things
> + * in here.
> + */
This time the locking is right and HPAGE_PMD_SIZE is used instead of
HPAGE_SIZE, thanks! I think all 5 patches can go in -mm and upstream
anytime (not mandatory for 2.6.38 but definitely we want this for
2.6.39).
BTW, Andi in his NUMA THP improvement series added a THP_SPLIT vmstat
per-cpu counter so that part removed from his series, is taken care by
him.
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
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next prev parent reply other threads:[~2011-02-22 13:37 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/$pid/smaps to not split huge pages Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-22 1:53 ` [PATCH 1/5] pagewalk: only split huge pages when necessary Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-22 21:21 ` David Rientjes
2011-02-22 21:21 ` David Rientjes
2011-02-23 15:30 ` Eric B Munson
2011-02-22 1:53 ` [PATCH 2/5] break out smaps_pte_entry() from smaps_pte_range() Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-22 21:21 ` David Rientjes
2011-02-22 21:21 ` David Rientjes
2011-02-23 15:30 ` Eric B Munson
2011-02-22 1:53 ` [PATCH 3/5] pass pte size argument in to smaps_pte_entry() Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-22 21:21 ` David Rientjes
2011-02-22 21:21 ` David Rientjes
2011-02-23 15:30 ` Eric B Munson
2011-02-22 1:53 ` [PATCH 4/5] teach smaps_pte_range() about THP pmds Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-22 13:35 ` Andrea Arcangeli [this message]
2011-02-22 13:35 ` Andrea Arcangeli
2011-02-22 21:22 ` David Rientjes
2011-02-22 21:22 ` David Rientjes
2011-02-23 15:31 ` Eric B Munson
2011-02-22 1:53 ` [PATCH 5/5] have smaps show transparent huge pages Dave Hansen
2011-02-22 1:53 ` Dave Hansen
2011-02-23 15:31 ` Eric B Munson
-- strict thread matches above, loose matches on Subject: below --
2011-02-09 19:54 [PATCH 0/5] fix up /proc/$pid/smaps to not split " Dave Hansen
2011-02-09 19:54 ` [PATCH 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
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