From: Steven Rostedt <rostedt@goodmis.org>
To: Dan Streetman <ddstreet@ieee.org>
Cc: Hugh Dickins <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>, Michal Hocko <mhocko@suse.cz>,
Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>,
Rik van Riel <riel@redhat.com>, Weijie Yang <weijieut@gmail.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Linux-MM <linux-mm@kvack.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 3/4] plist: add plist_rotate
Date: Tue, 6 May 2014 16:39:50 -0400 [thread overview]
Message-ID: <20140506163950.7e278f7c@gandalf.local.home> (raw)
In-Reply-To: <CALZtONAr7XGMB8LHwKRjqeEaWTEKBbwkUuP1RAZd04YQiwxrGw@mail.gmail.com>
On Tue, 6 May 2014 16:12:54 -0400
Dan Streetman <ddstreet@ieee.org> wrote:
> On Mon, May 5, 2014 at 10:18 PM, Steven Rostedt <rostedt@goodmis.org> wrote:
> > On Fri, 2 May 2014 15:02:29 -0400
> > Dan Streetman <ddstreet@ieee.org> wrote:
> >
> >> Add plist_rotate(), which moves the specified plist_node after
> >> all other same-priority plist_nodes in the list.
> >
> > This is a little confusing? You mean it takes a plist_node from a plist
> > and simply moves it to the end of the list of all other nodes of the
> > same priority?
>
> yes, exactly
>
> > Kind of like what a sched_yield() would do with a
> > SCHED_FIFO task? I wonder if we should call this "plist_yield()" then?
>
> I suppose it is similar, yes...I'll rename it in a v2 patch.
I'm open to other suggestions as well. What else can give you the idea
that it's putting a node at the end of its priority?
I added Peter to the Cc list because I know how much he loves
sched_yield() :-)
>
> >
> >>
> >> This is needed by swap, which has a plist of swap_info_structs
> >> and needs to use each same-priority swap_info_struct equally.
> >
> > "needs to use each same-priority swap_info_struct equally"
> >
> > -ENOCOMPUTE
>
> heh, yeah that needs a bit more explaining doesn't it :-)
>
> by "equally", I mean as swap writes pages out to its swap devices, it
> must write to any same-priority devices on a round-robin basis.
OK, I think you are suffering from "being too involved to explain
clearly" syndrome. :)
I still don't see the connection between swap pages and plist, and even
more so, why something would already be in a plist and then needs to be
pushed to the end of its priority.
>
> I'll update the comment in the v2 patch to try to explain clearer.
>
Please do. But explain it to someone that has no idea how plists are
used by the swap subsystem, and why you need to move a node to the end
of its priority.
Thanks,
-- Steve
next prev parent reply other threads:[~2014-05-06 20:39 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-13 10:42 [PATCH] mm: swap: Use swapfiles in priority order Mel Gorman
2014-02-13 15:58 ` Weijie Yang
2014-02-14 10:17 ` Mel Gorman
2014-02-14 13:33 ` Weijie Yang
[not found] ` <loom.20140214T135753-812@post.gmane.org>
[not found] ` <CABdxLJHS5kw0rpD=+77iQtc6PMeRXoWnh-nh5VzjjfGHJ5wLGQ@mail.gmail.com>
2014-02-24 8:28 ` Hugh Dickins
2014-04-12 21:00 ` [PATCH 0/2] swap: simplify/fix swap_list handling and iteration Dan Streetman
2014-04-12 21:00 ` [PATCH 1/2] swap: change swap_info singly-linked list to list_head Dan Streetman
2014-04-23 10:34 ` Mel Gorman
2014-04-24 0:17 ` Shaohua Li
2014-04-24 8:30 ` Mel Gorman
2014-04-24 18:48 ` Dan Streetman
2014-04-25 4:15 ` Weijie Yang
2014-05-02 20:00 ` Dan Streetman
2014-05-04 9:39 ` Bob Liu
2014-05-04 20:16 ` Dan Streetman
2014-04-25 8:38 ` Mel Gorman
2014-04-12 21:00 ` [PATCH 2/2] swap: use separate priority list for available swap_infos Dan Streetman
2014-04-23 13:14 ` Mel Gorman
2014-04-24 17:52 ` Dan Streetman
2014-04-25 8:49 ` Mel Gorman
2014-05-02 19:02 ` [PATCHv2 0/4] swap: simplify/fix swap_list handling and iteration Dan Streetman
2014-05-02 19:02 ` [PATCHv2 1/4] swap: change swap_info singly-linked list to list_head Dan Streetman
2014-05-02 19:02 ` [PATCH 2/4] plist: add helper functions Dan Streetman
2014-05-12 10:35 ` Mel Gorman
2014-05-02 19:02 ` [PATCH 3/4] plist: add plist_rotate Dan Streetman
2014-05-06 2:18 ` Steven Rostedt
2014-05-06 20:12 ` Dan Streetman
2014-05-06 20:39 ` Steven Rostedt [this message]
2014-05-06 21:47 ` Dan Streetman
2014-05-06 22:43 ` Steven Rostedt
2014-05-02 19:02 ` [PATCH 4/4] swap: change swap_list_head to plist, add swap_avail_head Dan Streetman
2014-05-05 15:51 ` Dan Streetman
2014-05-05 19:13 ` Steven Rostedt
2014-05-05 19:38 ` Peter Zijlstra
2014-05-09 20:42 ` [PATCH] plist: make CONFIG_DEBUG_PI_LIST selectable Dan Streetman
2014-05-09 21:17 ` Steven Rostedt
2014-05-12 11:11 ` [PATCH 4/4] swap: change swap_list_head to plist, add swap_avail_head Mel Gorman
2014-05-12 13:00 ` Dan Streetman
2014-05-12 16:38 ` [PATCHv3 0/4] swap: simplify/fix swap_list handling and iteration Dan Streetman
2014-05-12 16:38 ` [PATCHv2 1/4] swap: change swap_info singly-linked list to list_head Dan Streetman
2014-05-12 16:38 ` [PATCH 2/4] plist: add helper functions Dan Streetman
2014-05-12 16:38 ` [PATCHv2 3/4] plist: add plist_requeue Dan Streetman
2014-05-13 10:33 ` Mel Gorman
2014-05-12 16:38 ` [PATCHv2 4/4] swap: change swap_list_head to plist, add swap_avail_head Dan Streetman
2014-05-13 10:34 ` Mel Gorman
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