From: Al Viro <viro@ZenIV.linux.org.uk>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Nick Piggin <npiggin@kernel.dk>, Andi Kleen <ak@linux.intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 1/3] lglock: remove online variants of lock
Date: Tue, 8 May 2012 05:50:44 +0100 [thread overview]
Message-ID: <20120508045044.GJ22082@ZenIV.linux.org.uk> (raw)
In-Reply-To: <87txzrcoge.fsf@rustcorp.com.au>
On Tue, May 08, 2012 at 01:29:45PM +0930, Rusty Russell wrote:
> Optimizing the slow paths adds a lot of complexity. If you need to
> grab every lock often, you have other problems.
Applied, but I'm not too happy about the situation with vfsmount_lock ;-/
On kernels built for a lot of possible CPUs the loss of ..._online()
versions will get painful. OTOH, we can always put the map + single
spinlock + single notifier into lglock.c and reproduce the old logics.
I'll do a patch along those lines and put it on a separate branch;
then we'll be able to test and compare.
Contention from cpu map spinlock becoming shared between different
lglocks (all two of them) is not an issue - we never use the
files_lock one anyway (there we can't use _online variants).
next prev parent reply other threads:[~2012-05-08 4:50 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-27 23:22 [PATCH] cpumask: fix lg_lock/br_lock Rusty Russell
2012-02-27 23:53 ` Andrew Morton
2012-02-27 23:53 ` Andrew Morton
2012-02-28 8:43 ` Ingo Molnar
2012-02-28 11:25 ` Andi Kleen
2012-02-28 12:51 ` Ingo Molnar
2012-02-28 21:27 ` Andrew Morton
2012-02-29 5:44 ` Srivatsa S. Bhat
2012-02-29 9:17 ` Ingo Molnar
2012-02-29 11:12 ` Srivatsa S. Bhat
2012-03-01 7:38 ` Ingo Molnar
2012-03-01 9:15 ` Srivatsa S. Bhat
2012-03-01 9:45 ` Ingo Molnar
2012-03-01 9:56 ` Srivatsa S. Bhat
2012-03-01 8:12 ` Srivatsa S. Bhat
2012-03-01 8:24 ` Srivatsa S. Bhat
2012-03-01 8:12 ` Srivatsa S. Bhat
2012-03-01 8:15 ` [PATCH 1/3] CPU hotplug: Fix issues with callback registration Srivatsa S. Bhat
2012-03-01 8:27 ` Srivatsa S. Bhat
2012-03-01 8:15 ` Srivatsa S. Bhat
2012-03-01 8:16 ` [PATCH 2/3] CPU hotplug, arch/powerpc: Fix CPU hotplug " Srivatsa S. Bhat
2012-03-01 8:28 ` Srivatsa S. Bhat
2012-03-01 8:16 ` Srivatsa S. Bhat
2012-03-01 8:18 ` [PATCH 3/3] CPU hotplug, arch/sparc: " Srivatsa S. Bhat
2012-03-01 8:30 ` Srivatsa S. Bhat
2012-03-01 8:18 ` Srivatsa S. Bhat
2012-02-29 8:29 ` [PATCH] cpumask: fix lg_lock/br_lock Ingo Molnar
2012-02-29 8:58 ` Peter Zijlstra
2012-02-29 9:32 ` Ingo Molnar
2012-02-28 11:24 ` Andi Kleen
2012-03-05 7:02 ` Rusty Russell
2012-03-05 7:03 ` [PATCH 1/3] lglock: remove online variants of lock Rusty Russell
2012-04-20 11:12 ` Nick Piggin
2012-03-05 7:04 ` [PATCH 2/3] brlocks/lglocks: API cleanups Rusty Russell
2012-03-05 7:05 ` [PATCH 3/3] brlocks/lglocks: turn into functions Rusty Russell
2012-04-20 11:21 ` Nick Piggin
2012-05-07 3:39 ` Rusty Russell
2012-05-07 5:46 ` Al Viro
2012-05-08 3:59 ` [PATCH 1/3] lglock: remove online variants of lock Rusty Russell
2012-05-08 4:50 ` Al Viro [this message]
2012-05-08 6:12 ` Rusty Russell
2012-05-08 4:02 ` [PATCH 2/3] brlocks/lglocks: API cleanups Rusty Russell
2012-05-08 4:02 ` [PATCH 3/3] brlocks/lglocks: turn into functions Rusty Russell
2012-05-09 7:35 ` Nick Piggin
2012-05-09 7:35 ` Nick Piggin
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