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From: Tejun Heo <tj@kernel.org>
To: Dennis Zhou <dennisz@fb.com>
Cc: Christoph Lameter <cl@linux.com>,
	kernel-team@fb.com, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, Dennis Zhou <dennisszhou@gmail.com>
Subject: Re: [PATCH 10/10] percpu: add optimizations on allocation path for the bitmap allocator
Date: Mon, 17 Jul 2017 19:32:05 -0400	[thread overview]
Message-ID: <20170717233205.GD585283@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <20170716022315.19892-11-dennisz@fb.com>

On Sat, Jul 15, 2017 at 10:23:15PM -0400, Dennis Zhou wrote:
> From: "Dennis Zhou (Facebook)" <dennisszhou@gmail.com>
> 
> This patch adds two optimizations to the allocation path. The first is
> to not consider a chunk if the requested allocation cannot fit in the
> chunk's contig_hint. The benefit is that this avoids unncessary scanning
> over a chunk as the assumption is memory pressure is high and creating a
> new chunk has minimal consequences. This may fail when the contig_hint
> has poor alignment, but again we fall back on the high memory pressure
> argument.
> 
> The second is just a fail-fast mechanism. When allocating, a offset is
> identified within a block and then scanning is used to see if it will
> fit. An offset should never be returned unless it is known to fit, so
> here we just bind the scanning to the size of a block.
> 
> Signed-off-by: Dennis Zhou <dennisszhou@gmail.com>

Looks good to me and there's nothing wrong with these two
optimizations being in a separate patch but they might be too little
to help reviewing / debugging in any noticeable way.  It'd be great if
more significant parts can be separated out.  If not, this is fine
too.

Thanks.

-- 
tejun

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  reply	other threads:[~2017-07-17 23:32 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-16  2:23 [PATCH 00/10] percpu: replace percpu area map allocator with bitmap allocator Dennis Zhou
2017-07-16  2:23 ` [PATCH 01/10] percpu: pcpu-stats change void buffer to int buffer Dennis Zhou
2017-07-17 14:44   ` Tejun Heo
2017-07-16  2:23 ` [PATCH 02/10] percpu: change the format for percpu_stats output Dennis Zhou
2017-07-17 14:46   ` Tejun Heo
2017-07-16  2:23 ` [PATCH 03/10] percpu: expose pcpu_nr_empty_pop_pages in pcpu_stats Dennis Zhou
2017-07-17 14:47   ` Tejun Heo
2017-07-16  2:23 ` [PATCH 04/10] percpu: update the header comment and pcpu_build_alloc_info comments Dennis Zhou
2017-07-17 14:53   ` Tejun Heo
2017-07-16  2:23 ` [PATCH 05/10] percpu: change reserved_size to end page aligned Dennis Zhou
2017-07-16  4:01   ` kbuild test robot
2017-07-16  5:11   ` kbuild test robot
2017-07-17 16:46   ` Tejun Heo
2017-07-17 19:10     ` Dennis Zhou
2017-07-24 20:04     ` Dennis Zhou
2017-07-16  2:23 ` [PATCH 06/10] percpu: modify base_addr to be region specific Dennis Zhou
2017-07-17 18:57   ` Tejun Heo
2017-07-18 19:26   ` Josef Bacik
2017-07-18 19:36     ` Matthew Wilcox
2017-07-19 14:20       ` Josef Bacik
2017-07-16  2:23 ` [PATCH 07/10] percpu: fix misnomer in schunk/dchunk variable names Dennis Zhou
2017-07-17 19:10   ` Tejun Heo
2017-07-24 20:07     ` Dennis Zhou
2017-07-16  2:23 ` [PATCH 08/10] percpu: change the number of pages marked in the first_chunk bitmaps Dennis Zhou
2017-07-17 19:26   ` Tejun Heo
2017-07-24 20:13     ` Dennis Zhou
2017-07-16  2:23 ` [PATCH 09/10] percpu: replace area map allocator with bitmap allocator Dennis Zhou
2017-07-17 23:27   ` Tejun Heo
2017-07-24 21:37     ` Dennis Zhou
2017-07-19 19:11   ` Josef Bacik
2017-07-19 22:19     ` Dennis Zhou
2017-07-19 19:16   ` Josef Bacik
2017-07-19 22:13     ` Dennis Zhou
2017-07-16  2:23 ` [PATCH 10/10] percpu: add optimizations on allocation path for the " Dennis Zhou
2017-07-17 23:32   ` Tejun Heo [this message]
2017-07-18 19:15 ` [PATCH 00/10] percpu: replace percpu area map allocator with " Josef Bacik
2017-07-24 21:14   ` Dennis Zhou

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