From: Jan Kara <jack@suse.cz>
To: Waiman Long <longman@redhat.com>
Cc: Jan Kara <jack@suse.cz>, 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>,
Peter Zijlstra <peterz@infradead.org>,
Andi Kleen <andi@firstfloor.org>,
Dave Chinner <dchinner@redhat.com>,
Boqun Feng <boqun.feng@gmail.com>,
Davidlohr Bueso <dave@stgolabs.net>,
Waiman Long <Waiman.Long@hpe.com>
Subject: Re: [PATCH v6 4/6] lib/dlock-list: Make sibling CPUs share the same linked list
Date: Mon, 9 Oct 2017 09:26:13 +0200 [thread overview]
Message-ID: <20171009072613.GA17917@quack2.suse.cz> (raw)
In-Reply-To: <9ded5c76-4379-0339-6482-1f8bb590e3f2@redhat.com>
On Thu 05-10-17 10:57:07, Waiman Long wrote:
> On 10/05/2017 04:59 AM, Jan Kara wrote:
> > On Wed 04-10-17 17:20:05, Waiman Long wrote:
> >> int alloc_dlock_list_heads(struct dlock_list_heads *dlist)
> >> {
> >> - int idx;
> >> + int idx, cnt = nr_dlock_lists ? nr_dlock_lists : nr_cpu_ids;
> > Hum, is this there for the case where alloc_dlock_list_heads() is called
> > before nr_dlock_lists is initialized? But how can the dlist be used later
> > when it has larger number of lists and you don't know how many?
>
> The point is nr_dlock_lists <= nr_cpu_ids. Before nr_dlock_lists is
> initialized, the mapping table will map all cpus to the first entry. So
> the extra entries will just stay unused. At free time, they will all get
> de-allocated. I will clarify that with a comment.
OK, nice trick.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2017-10-09 7:26 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-04 21:20 [PATCH v6 0/6] vfs: Use dlock list for SB's s_inodes list Waiman Long
2017-10-04 21:20 ` [PATCH v6 1/6] lib/dlock-list: Distributed and lock-protected lists Waiman Long
2017-10-04 21:20 ` [PATCH v6 2/6] vfs: Remove unnecessary list_for_each_entry_safe() variants Waiman Long
2017-10-04 21:20 ` [PATCH v6 3/6] vfs: Use dlock list for superblock's inode list Waiman Long
2017-10-04 21:20 ` [PATCH v6 4/6] lib/dlock-list: Make sibling CPUs share the same linked list Waiman Long
2017-10-05 8:59 ` Jan Kara
2017-10-05 14:57 ` Waiman Long
2017-10-09 7:26 ` Jan Kara [this message]
2017-10-05 17:40 ` Davidlohr Bueso
2017-10-05 18:01 ` Waiman Long
2017-10-07 13:44 ` kbuild test robot
2017-10-07 14:38 ` kbuild test robot
2017-10-04 21:20 ` [PATCH v6 5/6] lib/dlock-list: Enable faster lookup with hashing Waiman Long
2017-10-05 9:14 ` Jan Kara
2017-10-05 11:06 ` Davidlohr Bueso
2017-10-04 21:20 ` [PATCH v6 6/6] lib/dlock-list: Provide IRQ-safe APIs Waiman Long
2017-10-04 22:46 ` Davidlohr Bueso
2017-10-05 13:40 ` Waiman Long
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