From: Waiman Long <longman@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Mike Kravetz <mike.kravetz@oracle.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, Davidlohr Bueso <dave@stgolabs.net>
Subject: Re: [PATCH 5/5] hugetlbfs: Limit wait time when trying to share huge PMD
Date: Wed, 11 Sep 2019 21:51:00 +0100 [thread overview]
Message-ID: <11361434-ca3d-78ae-e825-8521ee3bfbe6@redhat.com> (raw)
In-Reply-To: <20190911195745.GI29434@bombadil.infradead.org>
On 9/11/19 8:57 PM, Matthew Wilcox wrote:
> On Wed, Sep 11, 2019 at 04:05:37PM +0100, Waiman Long wrote:
>> To remove the unacceptable delays, we have to limit the amount of wait
>> time on the mmap_sem. So the new down_write_timedlock() function is
>> used to acquire the write lock on the mmap_sem with a timeout value of
>> 10ms which should not cause a perceivable delay. If timeout happens,
>> the task will abandon its effort to share the PMD and allocate its own
>> copy instead.
> If you do a v2, this is *NOT* the mmap_sem. It's the i_mmap_rwsem
> which protects a very different data structure from the mmap_sem.
>
Thanks for reminder. I should have read the code more carefully.
Cheers,
Longman
next prev parent reply other threads:[~2019-09-11 20:51 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 15:05 [PATCH 0/5] hugetlbfs: Disable PMD sharing for large systems Waiman Long
2019-09-11 15:05 ` [PATCH 1/5] locking/rwsem: Add down_write_timedlock() Waiman Long
2019-09-11 15:05 ` [PATCH 2/5] locking/rwsem: Enable timeout check when spinning on owner Waiman Long
2019-09-11 15:05 ` [PATCH 3/5] locking/osq: Allow early break from OSQ Waiman Long
2019-09-11 15:05 ` [PATCH 4/5] locking/rwsem: Enable timeout check when staying in the OSQ Waiman Long
2019-09-11 15:05 ` [PATCH 5/5] hugetlbfs: Limit wait time when trying to share huge PMD Waiman Long
2019-09-11 15:14 ` Matthew Wilcox
2019-09-11 15:44 ` Waiman Long
2019-09-11 17:03 ` Mike Kravetz
2019-09-11 17:15 ` Waiman Long
2019-09-11 17:22 ` Qian Cai
2019-09-11 17:28 ` Waiman Long
2019-09-11 16:01 ` Qian Cai
2019-09-11 16:34 ` Waiman Long
2019-09-11 19:42 ` Qian Cai
2019-09-11 20:54 ` Waiman Long
2019-09-11 21:57 ` Qian Cai
2019-09-11 19:57 ` Matthew Wilcox
2019-09-11 20:51 ` Waiman Long [this message]
2019-09-12 3:26 ` Mike Kravetz
2019-09-12 3:41 ` Matthew Wilcox
2019-09-12 4:40 ` Davidlohr Bueso
2019-09-16 13:53 ` Waiman Long
2019-09-12 9:06 ` Waiman Long
2019-09-12 16:43 ` Mike Kravetz
2019-09-13 18:23 ` Waiman Long
2019-09-12 5:36 ` Hillf Danton
2019-09-13 1:50 ` [PATCH 0/5] hugetlbfs: Disable PMD sharing for large systems Dave Chinner
2019-09-25 8:35 ` Peter Zijlstra
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