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Subject: Re: [RFC 10/26] mm, slub: do initial checks in ___slab_alloc() with
 irqs enabled
To:     Mel Gorman <mgorman@techsingularity.net>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Pekka Enberg <penberg@kernel.org>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Thomas Gleixner <tglx@linutronix.de>,
        Jesper Dangaard Brouer <brouer@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Jann Horn <jannh@google.com>
References: <20210524233946.20352-1-vbabka@suse.cz>
 <20210524233946.20352-11-vbabka@suse.cz>
 <20210525130436.GS30378@techsingularity.net>
From:   Vlastimil Babka <vbabka@suse.cz>
Message-ID: <c0a21f92-54ed-4e2f-01c5-d669fbb188bb@suse.cz>
Date:   Tue, 8 Jun 2021 14:13:20 +0200
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On 5/25/21 3:04 PM, Mel Gorman wrote:
> On Tue, May 25, 2021 at 01:39:30AM +0200, Vlastimil Babka wrote:
>> As another step of shortening irq disabled sections in ___slab_alloc(), don't
>> disable irqs until doing initial checks if there is a cached percpu slab and
>> it's suitable for our allocation.
>> 
>> Now we have to recheck c->page after actually disabling irqs as an allocation
>> in irq might have replaced it.
>> 
>> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> 
> Minor nit only -- consider adding a comment at the new_slab label that
> IRQs must be disabled already.

Good point, will use lockdep_assert_irqs_disabled() as that's a functional comment.

> Acked-by: Mel Gorman <mgorman@techsingularity.net>

Thanks.