From: "Ken Chen" <kenchen@google.com>
To: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: Badari Pulavarty <pbadari@gmail.com>, linux-mm <linux-mm@kvack.org>
Subject: Re: [rfc] more granular page table lock for hugepages
Date: Wed, 10 Oct 2007 00:50:13 -0700 [thread overview]
Message-ID: <b040c32a0710100050x51498022m247acf34da7bc3de@mail.gmail.com> (raw)
In-Reply-To: <b040c32a0710092310t22693865ue0b53acec85fae44@mail.gmail.com>
On 10/9/07, Ken Chen <kenchen@google.com> wrote:
> That's what I figures. In that case, why don't we get rid of all spin
> lock in the fast path of follow_hugetlb_pages.
>
> follow_hugetlb_page is called from get_user_pages, which should
> already hold mm->mmap_sem in read mode. That means page table tear
> down can not happen. We do a racy read on page table chain. If a
> race happened with another thread, no big deal, it will just fall into
> hugetlb_fault() which will then serialize with
> hugetlb_instantiation_mutex or mm->page_table_lock. And that's slow
> path anyway.
never mind. ftruncate can come through in another path removes
mapping without holding mm->mmap_sem. So much for the crazy idea.
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next prev parent reply other threads:[~2007-10-10 7:50 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-08 22:52 [rfc] more granular page table lock for hugepages Siddha, Suresh B
2007-10-09 20:23 ` Ken Chen
2007-10-09 21:05 ` Badari Pulavarty
2007-10-10 0:15 ` Siddha, Suresh B
2007-10-10 6:10 ` Ken Chen
2007-10-10 7:50 ` Ken Chen [this message]
2007-10-11 11:39 ` Nick Piggin
2007-10-12 20:34 ` Siddha, Suresh B
2007-10-13 23:27 ` Nick Piggin
2007-10-14 1:01 ` [rfc] lockless get_user_pages for dio (and more) Nick Piggin
2007-10-14 18:19 ` Siddha, Suresh B
2007-10-15 4:15 ` Nick Piggin
2007-10-15 12:25 ` Nick Piggin
2007-10-15 17:03 ` Badari Pulavarty
2007-10-15 17:49 ` Siddha, Suresh B
2007-10-15 17:54 ` Siddha, Suresh B
2007-10-15 20:21 ` Ken Chen
2007-10-16 2:15 ` Nick Piggin
2007-10-16 0:14 ` Dave Hansen
2007-10-16 3:26 ` Nick Piggin
2007-10-16 3:32 ` Nick Piggin
2007-12-10 21:30 ` Dave Kleikamp
2007-12-12 4:57 ` Nick Piggin
2007-12-12 5:11 ` Dave Kleikamp
2007-12-12 5:40 ` Nick Piggin
2008-01-16 19:58 ` Dave Kleikamp
2008-01-17 6:34 ` Nick Piggin
2008-01-24 7:06 ` Nick Piggin
2007-10-14 15:42 ` [rfc] more granular page table lock for hugepages Siddha, Suresh B
2007-10-15 4:17 ` Nick Piggin
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