From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dave Hansen <dave@sr71.net>, Andi Kleen <ak@linux.intel.com>,
dave.hansen@linux.intel.com, akpm@linux-foundation.org,
jack@suse.cz, viro@zeniv.linux.org.uk, eparis@redhat.com,
john@johnmccutchan.com, rlove@rlove.org,
tim.c.chen@linux.intel.com, linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH] fs: optimize inotify/fsnotify code for unwatched files
Date: Mon, 22 Jun 2015 20:52:29 +0200 [thread overview]
Message-ID: <20150622185229.GX3644@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20150622151121.GK3913@linux.vnet.ibm.com>
On Mon, Jun 22, 2015 at 08:11:21AM -0700, Paul E. McKenney wrote:
> That depends on how slow the resulting slow global state would be.
> We have some use cases (definitely KVM, perhaps also some of the VFS
> code) that need the current speed, as opposed to the profound slowness
> that three trips through synchronize_sched() would provide.
So what we have with that percpu-rwsem code that I send out earlier
today is a conditional smp_mb(), and I think we can do the same for
SRCU.
I'm just not sure !GP is common enough for all SRCU cases to be worth
doing.
Those that rely on sync_srcu() and who do it rarely would definitely
benefit. The same with those that rarely do call_srcu().
But those that heavily use call_srcu() would be better off with the
prolonged GP with 3 sync_sched() calls in.
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next prev parent reply other threads:[~2015-06-22 18:52 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-19 21:50 [RFC][PATCH] fs: optimize inotify/fsnotify code for unwatched files Dave Hansen
2015-06-19 23:33 ` Andi Kleen
2015-06-20 0:29 ` Paul E. McKenney
2015-06-20 0:39 ` Dave Hansen
2015-06-20 2:21 ` Paul E. McKenney
2015-06-20 18:02 ` Dave Hansen
2015-06-21 1:30 ` Paul E. McKenney
2015-06-22 13:28 ` Peter Zijlstra
2015-06-22 15:11 ` Paul E. McKenney
2015-06-22 15:20 ` Peter Zijlstra
2015-06-22 16:29 ` Paul E. McKenney
2015-06-22 19:03 ` Peter Zijlstra
2015-06-23 0:31 ` Paul E. McKenney
2015-06-22 18:50 ` Dave Hansen
2015-06-23 0:26 ` Paul E. McKenney
2015-06-24 16:50 ` Dave Hansen
2015-06-24 17:29 ` Paul E. McKenney
2015-06-22 18:52 ` Peter Zijlstra [this message]
2015-06-23 0:29 ` Paul E. McKenney
2015-06-23 15:17 ` Jan Kara
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