linux-kernel - Re: [PATCH net-next v5 01/13] mm: page_frag: add a test module for page

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Date: Thu, 30 May 2024 17:17:17 +0800
From: Yunsheng Lin <linyunsheng@...wei.com>
To: Jakub Kicinski <kuba@...nel.org>
CC: <davem@...emloft.net>, <pabeni@...hat.com>, <netdev@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, Alexander Duyck <alexander.duyck@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>, <linux-mm@...ck.org>
Subject: Re: [PATCH net-next v5 01/13] mm: page_frag: add a test module for
 page_frag

On 2024/5/30 8:29, Jakub Kicinski wrote:
> On Tue, 28 May 2024 20:55:51 +0800 Yunsheng Lin wrote:
>> Basing on the lib/objpool.c, change it to something like a
>> ptrpool, so that we can utilize that to test the correctness
>> and performance of the page_frag.
>>
>> The testing is done by ensuring that the fragments allocated
>> from a frag_frag_cache instance is pushed into a ptrpool
>> instance in a kthread binded to a specified cpu, and a kthread
>> binded to a specified cpu will pop the fragmemt from the
> 
> fragment
> 
>> ptrpool and free the fragmemt.
>>
>> We may refactor out the common part between objpool and ptrpool
>> if this ptrpool thing turns out to be helpful for other place.
> 
> Is this test actually meaningfully testing page_frag or rather
> the objpool construct and the scheduler? :S

For the objpool part, I guess it is ok to say that it is a
meaningfully testing for both page_frag and objpool if there is
changing to either of them.

For the scheduler part, this test provides the below module param
to avoid the the noise from scheduler.

+static int test_push_cpu;
+module_param(test_push_cpu, int, 0600);
+MODULE_PARM_DESC(test_push_cpu, "test cpu for pushing fragment");
+
+static int test_pop_cpu;
+module_param(test_pop_cpu, int, 0600);
+MODULE_PARM_DESC(test_pop_cpu, "test cpu for popping fragment");

Or is there any better idea for testing page_frag?

Thanks for taking a look.

> 
> .
>