From: Andrew Morton <akpm@linux-foundation.org>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Tejun Heo <tj@kernel.org>,
linux-kernel@vger.kernel.org,
Lai Jiangshan <jiangshanlai@gmail.com>,
Jens Axboe <axboe@kernel.dk>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-block@vger.kernel.org, dri-devel@lists.freedesktop.org,
Matthew Wilcox <mawilcox@microsoft.com>
Subject: Re: [RFC 00/10] implement alternative and much simpler id allocator
Date: Fri, 9 Dec 2016 14:01:40 -0800 [thread overview]
Message-ID: <20161209140140.5e0a68e2e1cf9861335bdf3b@linux-foundation.org> (raw)
In-Reply-To: <1481160187-9652-1-git-send-email-linux@rasmusvillemoes.dk>
On Thu, 8 Dec 2016 02:22:55 +0100 Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote:
> TL;DR: these patches save 250 KB of memory, with more low-hanging
> fruit ready to pick.
>
> While browsing through the lib/idr.c code, I noticed that the code at
> the end of ida_get_new_above() probably doesn't work as intended: Most
> users of ida use it via ida_simple_get(), and that starts by
> unconditionally calling ida_pre_get(), ensuring that ida->idr has
> 8==MAX_IDR_FREE idr_layers in its free list id_free. In the common
> case, none (or at most one) of these get used during
> ida_get_new_above(), and we only free one, leaving at least 6 (usually
> 7) idr_layers in the free list.
Please be aware of
http://ozlabs.org/~akpm/mmots/broken-out/reimplement-idr-and-ida-using-the-radix-tree.patch
http://lkml.kernel.org/r/1480369871-5271-68-git-send-email-mawilcox@linuxonhyperv.com
I expect we'll be merging patches 1-32 of that series into 4.10-rc1 and
the above patch (#33) into 4.11-rc1.
next prev parent reply other threads:[~2016-12-09 22:01 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-08 1:22 Rasmus Villemoes
2016-12-08 1:22 ` [RFC 01/10] lib/idr.c: reused free bitmaps are already clear Rasmus Villemoes
2016-12-08 1:22 ` [RFC 02/10] lib/idr.c: delete useless condition Rasmus Villemoes
2016-12-08 1:22 ` [RFC 03/10] lib/idr.c: only fill ida->idr when needed Rasmus Villemoes
2016-12-08 1:22 ` [RFC 04/10] lib/tida.c: a very simple integer id allocator Rasmus Villemoes
2016-12-08 1:23 ` [RFC 05/10] kernel/workqueue.c: replace id allocator ida with tida Rasmus Villemoes
2016-12-08 1:23 ` [RFC 06/10] block: use tida as small id allocator Rasmus Villemoes
2016-12-08 3:56 ` Jens Axboe
2016-12-08 11:02 ` Greg Kroah-Hartman
2016-12-08 1:23 ` [RFC 07/10] drivers/base/platform.c: use simpler " Rasmus Villemoes
2016-12-08 1:23 ` [RFC 08/10] lib/tida.c: introduce tida_get_above Rasmus Villemoes
2016-12-08 1:23 ` [RFC 09/10] drm: use simpler id allocator Rasmus Villemoes
2016-12-08 1:23 ` [RFC 10/10] fs/devpts: use tida for id allocation Rasmus Villemoes
2016-12-09 13:49 ` [RFC 00/10] implement alternative and much simpler id allocator Tejun Heo
2016-12-09 22:01 ` Andrew Morton [this message]
2016-12-12 17:09 ` Tejun Heo
2016-12-12 17:35 ` Matthew Wilcox
2016-12-12 18:05 ` Tejun Heo
2016-12-16 19:14 ` Matthew Wilcox
2016-12-16 20:32 ` Rasmus Villemoes
2016-12-16 21:09 ` Matthew Wilcox
2016-12-17 13:28 ` Matthew Wilcox
2016-12-22 23:46 ` Rasmus Villemoes
2016-12-23 17:03 ` Matthew Wilcox
2016-12-18 2:42 ` Matthew Wilcox
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