Re: [PATCH v3] mm: slub: avoid wake up kswapd in set_track_prepare

[Vlastimil Babka]

On 8/29/25 13:29, yangshiguang wrote:
> At 2025-08-27 16:40:21, "Vlastimil Babka" <vbabka@xxxxxxx> 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:

/*
 * 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