From: Andrew Morton <akpm@linux-foundation.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: linux-kernel@vger.kernel.org, Vlastimil Babka <vbabka@suse.cz>,
Mel Gorman <mgorman@techsingularity.net>,
Christoph Lameter <cl@linux.com>, Roman Gushchin <guro@fb.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
linux-mm@kvack.org
Subject: Re: [PATCH] slab.h: Avoid using & for logical and of booleans
Date: Mon, 5 Nov 2018 13:13:05 -0800 [thread overview]
Message-ID: <20181105131305.574d85469f08a4b76592feb6@linux-foundation.org> (raw)
In-Reply-To: <20181105204000.129023-1-bvanassche@acm.org>
On Mon, 5 Nov 2018 12:40:00 -0800 Bart Van Assche <bvanassche@acm.org> wrote:
> This patch suppresses the following sparse warning:
>
> ./include/linux/slab.h:332:43: warning: dubious: x & !y
>
> ...
>
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -329,7 +329,7 @@ static __always_inline enum kmalloc_cache_type kmalloc_type(gfp_t flags)
> * If an allocation is both __GFP_DMA and __GFP_RECLAIMABLE, return
> * KMALLOC_DMA and effectively ignore __GFP_RECLAIMABLE
> */
> - return type_dma + (is_reclaimable & !is_dma) * KMALLOC_RECLAIM;
> + return type_dma + is_reclaimable * !is_dma * KMALLOC_RECLAIM;
> }
>
> /*
I suppose so.
That function seems too clever for its own good :(. I wonder if these
branch-avoiding tricks are really worthwhile.
next parent reply other threads:[~2018-11-05 21:13 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20181105204000.129023-1-bvanassche@acm.org>
2018-11-05 21:13 ` Andrew Morton [this message]
2018-11-05 21:48 ` Bart Van Assche
2018-11-05 22:14 ` Rasmus Villemoes
2018-11-05 22:40 ` Bart Van Assche
2018-11-05 22:48 ` Alexander Duyck
2018-11-06 0:01 ` Bart Van Assche
2018-11-06 0:11 ` Alexander Duyck
2018-11-06 0:32 ` Bart Van Assche
2018-11-06 17:20 ` Alexander Duyck
2018-11-06 17:48 ` Bart Van Assche
2018-11-06 18:17 ` Alexander Duyck
2018-11-06 9:45 ` William Kucharski
[not found] ` <62188a351f2249188ce654ee03c894b1@AcuMS.aculab.com>
[not found] ` <e44e6c8b-e4e4-e7cb-a5ca-88e9559eb0d7@suse.cz>
[not found] ` <3c9adab0f1f74c46a60b3d4401030337@AcuMS.aculab.com>
[not found] ` <60deb90d-e521-39e5-5072-fc9efb98e365@suse.cz>
[not found] ` <9af3ac1d43bb422cb3c41e7e8e422e6e@AcuMS.aculab.com>
[not found] ` <cbc1fc52-dc8c-aa38-8f29-22da8bcd91c1@suse.cz>
[not found] ` <20181109110019.c82fba8125d4e2891fbe4a6c@linux-foundation.org>
[not found] ` <b8ffd59b-0d15-9c98-b9ea-ad71e4c0c734@suse.cz>
[not found] ` <bf7c2a6b801a4430bf842fc20e826db6@AcuMS.aculab.com>
[not found] ` <aa5975b6-58ed-5a3e-7de1-4b1384f88457@suse.cz>
2018-11-21 13:22 ` Vlastimil Babka
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