From: Tejun Heo <tj@kernel.org>
To: Kent Overstreet <kmo@daterainc.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
Stephen Rothwell <sfr@canb.auug.org.au>,
Fengguang Wu <fengguang.wu@intel.com>
Subject: Re: [PATCH] idr: Document ida tree sections
Date: Tue, 13 Aug 2013 18:19:28 -0400 [thread overview]
Message-ID: <20130813221928.GE28996@mtj.dyndns.org> (raw)
In-Reply-To: <20130813221308.GA11980@kmo-pixel>
Hello,
On Tue, Aug 13, 2013 at 03:13:08PM -0700, Kent Overstreet wrote:
> If you're convinced this is a real issue though - how about
It is a real issue. Large order allocation is fine for optimization
but shouldn't be depended upon. It does fail easily without
compaction and compaction is heavy-ass operation which will blow up
any minute performance advantage you might get from avoiding proper
radix tree implementation.
> IDA_SECTION_SIZE conditional on CONFIG_COMPACTION, so we use order 2 or
> 3 allocations if CONFIG_COMPACTION=n?
>
> Then the max size toplevel array of pointers to segments would be
> bigger, but that's only an issue when we're allocating up to near
> INT_MAX ids, so it's difficult to see how _that_ would be an issue on a
> small/embedded system... and we could even use vmalloc for that
> allocation when the size of that array is > IDA_SECTION_SIZE.
What about cyclic allocations then? This is natrually a radix tree
problem. I don't know why you're resisting radix tree so much here.
Thanks.
--
tejun
next prev parent reply other threads:[~2013-08-13 22:19 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-07 17:34 IDA/IDR rewrite, percpu ida Kent Overstreet
2013-08-07 17:34 ` [PATCH 03/10] idr: Rewrite ida Kent Overstreet
2013-08-07 20:22 ` Tejun Heo
2013-08-07 20:51 ` [PATCH] idr: Document ida tree sections Kent Overstreet
2013-08-09 14:57 ` Tejun Heo
2013-08-13 22:13 ` Kent Overstreet
2013-08-13 22:19 ` Tejun Heo [this message]
2013-08-13 22:27 ` Kent Overstreet
2013-08-13 22:44 ` Tejun Heo
2013-08-13 22:59 ` Kent Overstreet
2013-08-13 23:22 ` Tejun Heo
2013-08-13 23:51 ` Kent Overstreet
2013-08-13 23:59 ` Tejun Heo
2013-08-15 0:04 ` Kent Overstreet
2013-08-15 0:22 ` Tejun Heo
2013-08-13 22:33 ` Kent Overstreet
2013-08-07 17:34 ` [PATCH 04/10] idr: Percpu ida Kent Overstreet
2013-08-07 17:56 ` Christoph Lameter
2013-08-07 18:33 ` Kent Overstreet
2013-08-07 19:40 ` Christoph Lameter
2013-08-07 19:57 ` [PATCH] idr: Use this_cpu_ptr() for percpu_ida Kent Overstreet
2013-08-08 14:32 ` Christoph Lameter
2013-08-20 21:19 ` Nicholas A. Bellinger
2013-08-20 21:29 ` Andrew Morton
2013-08-21 2:01 ` Kent Overstreet
2013-08-21 2:07 ` Tejun Heo
2013-08-21 2:31 ` Kent Overstreet
2013-08-21 11:59 ` Tejun Heo
2013-08-21 21:09 ` Kent Overstreet
2013-08-21 21:16 ` Tejun Heo
2013-08-21 21:24 ` Kent Overstreet
2013-08-21 21:31 ` Tejun Heo
2013-08-21 14:32 ` Christoph Lameter
2013-08-21 17:49 ` Nicholas A. Bellinger
2013-08-21 20:49 ` Andrew Morton
2013-08-22 16:44 ` Christoph Lameter
2013-08-22 16:56 ` Jens Axboe
2013-08-07 17:46 ` [PATCH 05/10] idr: Kill old deprecated idr interfaces Kent Overstreet
2013-08-07 17:46 ` [PATCH 06/10] idr: Rename idr_get_next() -> idr_find_next() Kent Overstreet
2013-08-07 17:46 ` [PATCH 08/10] idr: Reimplement idr on top of ida/radix trees Kent Overstreet
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