From: Peter Zijlstra <peterz@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: Waiman Long <Waiman.Long@hpe.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jan Kara <jack@suse.com>, Jeff Layton <jlayton@poochiereds.net>,
"J. Bruce Fields" <bfields@fieldses.org>,
Tejun Heo <tj@kernel.org>,
Christoph Lameter <cl@linux-foundation.org>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Ingo Molnar <mingo@redhat.com>, Andi Kleen <andi@firstfloor.org>,
Dave Chinner <dchinner@redhat.com>,
Scott J Norton <scott.norton@hp.com>,
Douglas Hatch <doug.hatch@hp.com>
Subject: Re: [RFC PATCH 1/2] lib/percpu-list: Per-cpu list with associated per-cpu locks
Date: Wed, 17 Feb 2016 12:05:20 +0100 [thread overview]
Message-ID: <20160217110520.GN6375@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160217110040.GB6357@twins.programming.kicks-ass.net>
On Wed, Feb 17, 2016 at 12:00:40PM +0100, Peter Zijlstra wrote:
> On Wed, Feb 17, 2016 at 08:53:18PM +1100, Dave Chinner wrote:
> > > +/**
> > > + * for_all_percpu_list_entries - iterate over all the per-cpu list with locking
But the locking is 'pointless'. You only lock one per-cpu sublist at a
time, therefore the list can be modified concurrently anyhow.
So why not use RCU for the list iteration and avoid potentially large
lock hold times?
> > > + * @pos: the type * to use as a loop cursor for the current .
> > > + * @next: an internal type * variable pointing to the next entry
> > > + * @pchead: an internal struct list * of percpu list head
> > > + * @pclock: an internal variable for the current per-cpu spinlock
> > > + * @head: the head of the per-cpu list
> > > + * @member: the name of the per-cpu list within the struct
> > > + */
next prev parent reply other threads:[~2016-02-17 11:05 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-17 1:31 [RFC PATCH 0/2] vfs: Use per-cpu list for SB's s_inodes list Waiman Long
2016-02-17 1:31 ` [RFC PATCH 1/2] lib/percpu-list: Per-cpu list with associated per-cpu locks Waiman Long
2016-02-17 9:53 ` Dave Chinner
2016-02-17 11:00 ` Peter Zijlstra
2016-02-17 11:05 ` Peter Zijlstra [this message]
2016-02-17 16:16 ` Waiman Long
2016-02-17 16:22 ` Peter Zijlstra
2016-02-17 16:27 ` Christoph Lameter
2016-02-17 17:12 ` Waiman Long
2016-02-17 17:18 ` Peter Zijlstra
2016-02-17 17:41 ` Waiman Long
2016-02-17 18:22 ` Peter Zijlstra
2016-02-17 18:45 ` Waiman Long
2016-02-17 19:39 ` Peter Zijlstra
2016-02-17 11:10 ` Dave Chinner
2016-02-17 11:26 ` Peter Zijlstra
2016-02-17 11:36 ` Peter Zijlstra
2016-02-17 15:56 ` Waiman Long
2016-02-17 16:02 ` Peter Zijlstra
2016-02-17 15:13 ` Christoph Lameter
2016-02-17 1:31 ` [RRC PATCH 2/2] vfs: Use per-cpu list for superblock's inode list Waiman Long
2016-02-17 7:16 ` Ingo Molnar
2016-02-17 15:40 ` Waiman Long
2016-02-17 10:37 ` Dave Chinner
2016-02-17 16:08 ` Waiman Long
2016-02-18 23:58 ` [RFC PATCH 0/2] vfs: Use per-cpu list for SB's s_inodes list Dave Chinner
2016-02-19 21:04 ` Long, Wai Man
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