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From: Daniel Wagner <daniel.wagner@bmw-carit.de>
To: Andi Kleen <andi@firstfloor.org>
Cc: Jeff Layton <jlayton@poochiereds.net>,
	<linux-fsdevel@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	John Kacur <jkacur@redhat.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	"J. Bruce Fields" <bfields@fieldses.org>
Subject: Re: [RFC v1 0/5] fs/locks: Use plain percpu spinlocks instead of lglock to protect file_lock
Date: Tue, 24 Feb 2015 16:58:26 +0100	[thread overview]
Message-ID: <54EC9FA2.1030000@bmw-carit.de> (raw)
In-Reply-To: <87vbiwwotb.fsf@tassilo.jf.intel.com>

On 02/20/2015 05:05 PM, Andi Kleen wrote:
> Daniel Wagner <daniel.wagner@bmw-carit.de> writes:
>>
>> I am looking at how to get rid of lglock. Reason being -rt is not too
>> happy with that lock, especially that it uses arch_spinlock_t and
> 
> AFAIK it could just use normal spinlock. Have you tried that?

I have tried it. At least fs/locks.c didn't blow up. The benchmark
results (lockperf) indicated that using normal spinlocks is even
slightly faster. Simply converting felt like cheating. It might be
necessary for the other user (kernel/stop_machine.c). Currently it looks
like there is some additional benefit getting lglock away in fs/locks.c.

cheers,
daniel

  reply	other threads:[~2015-02-24 15:58 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-02-20 14:39 [RFC v1 0/5] fs/locks: Use plain percpu spinlocks instead of lglock to protect file_lock Daniel Wagner
2015-02-20 14:39 ` [RFC v1 1/5] locks: Remove unnecessary IS_POSIX test Daniel Wagner
2015-02-20 14:39 ` [RFC v1 2/5] locks: Split insert/delete block functions into flock/posix parts Daniel Wagner
2015-02-20 14:39 ` [RFC v1 3/5] seq_file: Add percpu seq_hlist helpers with locking iterators Daniel Wagner
2015-02-20 14:39 ` [RFC v1 4/5] locks: Use percpu spinlocks to protect file_lock_list Daniel Wagner
2015-02-20 14:39 ` [RFC v1 5/5] locks: Use blocked_lock_lock only to protect blocked_hash Daniel Wagner
2015-02-20 16:05 ` [RFC v1 0/5] fs/locks: Use plain percpu spinlocks instead of lglock to protect file_lock Andi Kleen
2015-02-24 15:58   ` Daniel Wagner [this message]
2015-02-24 21:06     ` Jeff Layton
2015-02-27 15:01       ` Daniel Wagner
2015-02-27 15:30         ` Jeff Layton
2015-03-02 12:58           ` Daniel Wagner
2015-03-03  0:29             ` Jeff Layton
2015-03-04 14:03               ` Daniel Wagner

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