From: Jan Kara <jack@suse.cz>
To: Waiman Long <longman@redhat.com>
Cc: 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>
Subject: Re: [PATCH v6 5/6] lib/dlock-list: Enable faster lookup with hashing
Date: Thu, 5 Oct 2017 11:14:06 +0200 [thread overview]
Message-ID: <20171005091406.GD28132@quack2.suse.cz> (raw)
In-Reply-To: <1507152007-28753-6-git-send-email-longman@redhat.com>
On Wed 04-10-17 17:20:06, Waiman Long wrote:
> Insertion and deletion is relatively cheap and mostly contention
> free for dlock-list. Lookup, on the other hand, can be rather costly
> because all the lists in a dlock-list will have to be iterated.
>
> Currently dlock-list insertion is based on the cpu that the task is
> running on. So a given object can be inserted into any one of the
> lists depending on what the current cpu is.
>
> This patch provides an alternative way of list selection. The caller
> can provide a object context which will be hashed to one of the list
> in a dlock-list. The object can then be added into that particular
> list. Lookup can be done by iterating elements in the provided list
> only instead of all the lists in a dlock-list.
>
> The new APIs are:
>
> struct dlock_list_head *dlock_list_hash(struct dlock_list_heads *, void *);
> void dlock_list_add(struct dlock_list_node *, struct dlock_list_head *);
>
> Signed-off-by: Waiman Long <longman@redhat.com>
OK, this makes sense but do you have any particular user in mind? In
particular I'm not sure how big advantage this API brings over an existing
one in include/linux/list_bl.h. Sure it's a tradeoff between bitlock /
spinlock but is there a user where it matters?
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2017-10-05 9:14 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
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 [this message]
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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