From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
To: Hillf Danton <dhillf@gmail.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>,
Andi Kleen <andi@firstfloor.org>,
Wu Fengguang <fengguang.wu@intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/6] thp: optimize away unnecessary page table locking
Date: Fri, 13 Jan 2012 10:14:25 -0500 [thread overview]
Message-ID: <4F104A51.2000701@ah.jp.nec.com> (raw)
In-Reply-To: <CAJd=RBB6azf9nin5tjqTtHakxy896rCxr6ErK4p2KDrke_goEA@mail.gmail.com>
Hi Hillf,
(1/13/2012 7:04), Hillf Danton wrote:
[...]
>> +/*
>> + * Returns 1 if a given pmd is mapping a thp and stable (not under splitting.)
>> + * Returns 0 otherwise. Note that if it returns 1, this routine returns without
>> + * unlocking page table locks. So callers must unlock them.
>> + */
>> +int pmd_trans_huge_stable(pmd_t *pmd, struct vm_area_struct *vma)
>> +{
>> + VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem));
>> +
>> + if (!pmd_trans_huge(*pmd))
>> + return 0;
>> +
>> + spin_lock(&vma->vm_mm->page_table_lock);
>> + if (likely(pmd_trans_huge(*pmd))) {
>> + if (pmd_trans_splitting(*pmd)) {
>> + spin_unlock(&vma->vm_mm->page_table_lock);
>> + wait_split_huge_page(vma->anon_vma, pmd);
>> + return 0;
>> + } else {
>
> spin_unlock(&vma->vm_mm->page_table_lock); yes?
No. Unlocking is supposed to be done by the caller as commented.
Thanks,
Naoya
>
>> + /* Thp mapped by 'pmd' is stable, so we can
>> + * handle it as it is. */
>> + return 1;
>> + }
>> + }
>> + spin_unlock(&vma->vm_mm->page_table_lock);
>> + return 0;
>> +}
>> +
next prev parent reply other threads:[~2012-01-13 15:20 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-12 19:34 [PATCH 0/6 v3] pagemap handles transparent hugepage Naoya Horiguchi
2012-01-12 19:34 ` [PATCH 1/6] pagemap: avoid splitting thp when reading /proc/pid/pagemap Naoya Horiguchi
2012-01-14 17:00 ` Andrea Arcangeli
2012-01-15 12:06 ` Andrea Arcangeli
2012-01-16 17:18 ` Naoya Horiguchi
2012-01-12 19:34 ` [PATCH 2/6] thp: optimize away unnecessary page table locking Naoya Horiguchi
2012-01-13 12:04 ` Hillf Danton
2012-01-13 15:14 ` Naoya Horiguchi [this message]
2012-01-14 3:24 ` Hillf Danton
2012-01-14 17:19 ` Andrea Arcangeli
2012-01-12 19:34 ` [PATCH 3/6] pagemap: export KPF_THP Naoya Horiguchi
2012-01-12 19:34 ` [PATCH 4/6] pagemap: document KPF_THP and make page-types aware of it Naoya Horiguchi
2012-01-12 19:34 ` [PATCH 5/6] introduce thp_ptep_get() Naoya Horiguchi
2012-01-12 19:34 ` [PATCH 6/6] pagemap: introduce data structure for pagemap entry Naoya Horiguchi
2012-01-13 21:54 ` [PATCH 0/6 v3] pagemap handles transparent hugepage Andrew Morton
2012-01-16 17:19 [PATCH 2/6] thp: optimize away unnecessary page table locking Naoya Horiguchi
2012-01-27 23:02 [PATCH 0/6 v4] pagemap handles transparent hugepage Naoya Horiguchi
2012-01-27 23:02 ` [PATCH 2/6] thp: optimize away unnecessary page table locking Naoya Horiguchi
2012-01-28 11:23 ` Hillf Danton
2012-01-28 22:33 ` Naoya Horiguchi
2012-01-30 6:22 ` KAMEZAWA Hiroyuki
2012-02-02 5:27 ` Naoya Horiguchi
2012-02-02 8:32 ` KAMEZAWA Hiroyuki
2012-02-08 15:51 [PATCH 0/6 v5] pagemap handles transparent hugepage Naoya Horiguchi
2012-02-08 15:51 ` [PATCH 2/6] thp: optimize away unnecessary page table locking Naoya Horiguchi
2012-02-09 2:19 ` KAMEZAWA Hiroyuki
2012-02-19 21:21 ` Hugh Dickins
2012-02-20 7:28 ` Naoya Horiguchi
2012-02-20 11:38 ` Hugh Dickins
2012-02-20 11:54 ` Jiri Slaby
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