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From: Roman Gushchin <roman.gushchin@linux.dev>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Zhaoyang Huang <huangzhaoyang@gmail.com>,
	"zhaoyang.huang" <zhaoyang.huang@unisoc.com>,
	Roman Gushchin <guro@fb.com>, Minchan Kim <minchan@kernel.org>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	ke.wang@unisoc.com
Subject: Re: [PATCHv5] mm: optimization on page allocation when CMA enabled
Date: Mon, 9 Oct 2023 18:31:43 -0700	[thread overview]
Message-ID: <ZSSpfw_VdFkus4F5@P9FQF9L96D> (raw)
In-Reply-To: <20231009171415.cfc26b45c2f9f4489afe16c2@linux-foundation.org>

On Mon, Oct 09, 2023 at 05:14:15PM -0700, Andrew Morton wrote:
> On Sun, 8 Oct 2023 15:54:40 +0800 Zhaoyang Huang <huangzhaoyang@gmail.com> wrote:
> 
> > > Roman previously asked
> > >
> > > : Also I'm a bit concerned about potential performance implications.
> > > : Would be great to provide some benchmarks or some data.  Probably it's
> > > : ok because of we have pcp caches on top, but I'm not 100% sure.
> > >
> > > Are you able to perform such testing and tell us the result?
> > I have applied this patch in a v5.4 based ANDROID system and got no
> > regression problem. Actually, this commit is aimed to have
> > alloc_pages(GFP_USER) use CMA instead of stealing U&R(could lead to
> > GFP_KERNEL fail) only when zone's free pages and free cma are around
> > WATERMARK_LOW/MIN which would NOT affect most scenarios.
> 
> OK, thanks.
> 
> Could the appropriate people please take a look at this?  It has been
> in mm-unstable since May.

I have 2 concerns:
1) it's still hard to understand the commit message and comments, I can
   only reverse-engineer it based on the code changes;
2) performance concerns I expressed earlier are not addressed. Idk what's
   a good benchmark for the page allocator, probably something i/o or
   networking heavy.

On the positive side I believe that the patch is solving a real problem.


  reply	other threads:[~2023-10-10  1:31 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-05-11  5:22 [PATCHv5] mm: optimization on page allocation when CMA enabled zhaoyang.huang
2023-10-06 21:17 ` Andrew Morton
2023-10-08  7:54   ` Zhaoyang Huang
2023-10-10  0:14     ` Andrew Morton
2023-10-10  1:31       ` Roman Gushchin [this message]
2023-10-10  1:42         ` Zhaoyang Huang

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