linux-kernel - Re:Re: [PATCH v3] mm: slub: avoid wake up kswapd in set_track

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Message-ID: <15cc44af.7a6.198f8a95fb5.Coremail.yangshiguang1011@163.com>
Date: Sat, 30 Aug 2025 09:48:26 +0800 (CST)
From: yangshiguang  <yangshiguang1011@....com>
To: "Vlastimil Babka" <vbabka@...e.cz>
Cc: "Harry Yoo" <harry.yoo@...cle.com>,
	"Matthew Wilcox" <willy@...radead.org>, akpm@...ux-foundation.org,
	cl@...two.org, rientjes@...gle.com, roman.gushchin@...ux.dev,
	glittao@...il.com, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	yangshiguang <yangshiguang@...omi.com>, stable@...r.kernel.org
Subject: Re:Re: [PATCH v3] mm: slub: avoid wake up kswapd in
 set_track_prepare





At 2025-08-29 21:08:58, "Vlastimil Babka" <vbabka@...e.cz> wrote:
>On 8/29/25 13:29, yangshiguang wrote:
>> At 2025-08-27 16:40:21, "Vlastimil Babka" <vbabka@...e.cz> wrote:
>> 
>>>> 
>>>>>
>>>> 
>>>> How about this? 
>>>> 
>>>>         /* Preemption is disabled in ___slab_alloc() */
>>>> -       gfp_flags &= ~(__GFP_DIRECT_RECLAIM);
>>>> +       gfp_flags = (gfp_flags & ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL)) |
>>>> +                                       __GFP_NOWARN;
>>>
>>>I'd suggest using gfp_nested_flags() and & ~(__GFP_DIRECT_RECLAIM);
>>>
>> 
>> However, gfp has been processed by gfp_nested_mask() in
>> stack_depot_save_flags().
>
>Aha, didn't notice. Good to know!
>
>> Still need to call here?
>
>No then we can indeed just mask out __GFP_DIRECT_RECLAIM.
>
>Maybe the comment could say something like:

>

sure. Express clearly.


>/*
> * Preemption is disabled in ___slab_alloc() so we need to disallow
> * blocking. The flags are further adjusted by gfp_nested_mask() in
> * stack_depot itself.
> */
>> set_track_prepare()
>> ->stack_depot_save_flags()
>> 
>>>>  >-- 
>>>>>Cheers,
>>>>>Harry / Hyeonggon