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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Jens Axboe <jens.axboe@oracle.com>,
	linux-kernel@vger.kernel.org, Alan.Brunelle@hp.com,
	arjan@linux.intel.com, dgc@sgi.com, npiggin@suse.de,
	Andrew Morton <akpm@linux-foundation.org>,
	Vegard Nossum <vegard.nossum@gmail.com>,
	Pekka Enberg <penberg@gmail.com>
Subject: Re: [patch] block layer: kmemcheck fixes
Date: Thu, 7 Feb 2008 09:42:56 -0800 (PST)	[thread overview]
Message-ID: <alpine.LFD.1.00.0802070940230.2883@woody.linux-foundation.org> (raw)
In-Reply-To: <20080207104901.GF16735@elte.hu>



On Thu, 7 Feb 2008, Ingo Molnar wrote:
>  	INIT_HLIST_NODE(&rq->hash);
>  	RB_CLEAR_NODE(&rq->rb_node);
> -	rq->ioprio = 0;
> -	rq->buffer = NULL;
> -	rq->ref_count = 1;
> -	rq->q = q;
> -	rq->special = NULL;
> -	rq->data_len = 0;
> -	rq->data = NULL;
> -	rq->nr_phys_segments = 0;
> -	rq->sense = NULL;
> -	rq->end_io = NULL;
> -	rq->end_io_data = NULL;
> -	rq->completion_data = NULL;
> -	rq->next_rq = NULL;
> +	rq->completion_data		= NULL;
> +	/* rq->elevator_private			*/
> +	/* rq->elevator_private2		*/
> +	/* rq->rq_disk				*/
> +	/* rq->start_time			*/
> +	rq->nr_phys_segments		= 0;
> +	/* rq->nr_hw_segments			*/
> +	rq->ioprio			= 0;
> +	rq->special			= NULL;
> +	rq->buffer			= NULL;
...

Can we please just stop doing these one-by-one assignments, and just do 
something like

	memset(rq, 0, sizeof(*rq));
	rq->q = q;
	rq->ref_count = 1;
	INIT_HLIST_NODE(&rq->hash);
	RB_CLEAR_NODE(&rq->rb_node);

instead?

The memset() is likely faster and smaller than one-by-one assignments 
anyway, even if the one-by-ones can avoid initializing some field or there 
ends up being a double initialization..

			Linus

  reply	other threads:[~2008-02-07 17:44 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-07  9:18 [PATCH 0/8] IO queuing and complete affinity Jens Axboe
2008-02-07  9:18 ` [PATCH 1/8] block: split softirq handling into blk-softirq.c Jens Axboe
2008-02-07  9:18 ` [PATCH 2/8] Add interface for queuing work on a specific CPU Jens Axboe
2008-02-07  9:45   ` Andrew Morton
2008-02-07  9:49     ` Jens Axboe
2008-02-07 17:44       ` Harvey Harrison
2008-02-11 10:51     ` Oleg Nesterov
2008-02-07  9:19 ` [PATCH 3/8] block: make kblockd_schedule_work() take the queue as parameter Jens Axboe
2008-02-07  9:19 ` [PATCH 4/8] x86: add support for remotely triggering the block softirq Jens Axboe
2008-02-07 10:07   ` Ingo Molnar
2008-02-07 10:17     ` Jens Axboe
2008-02-07 10:25       ` Ingo Molnar
2008-02-07 10:31         ` Jens Axboe
2008-02-07 10:38           ` Ingo Molnar
2008-02-07 14:18             ` Jens Axboe
2008-02-07 10:49           ` [patch] block layer: kmemcheck fixes Ingo Molnar
2008-02-07 17:42             ` Linus Torvalds [this message]
2008-02-07 17:55               ` Jens Axboe
2008-02-07 19:31               ` Ingo Molnar
2008-02-07 20:06                 ` Jens Axboe
2008-02-08  1:22               ` David Miller
2008-02-08  1:28                 ` Linus Torvalds
2008-02-08 15:09                 ` Arjan van de Ven
2008-02-08 22:44                   ` Nick Piggin
2008-02-08 22:56                     ` Arjan van de Ven
2008-02-08 23:58                       ` Nick Piggin
2008-02-08 11:38               ` Jens Axboe
2008-02-07  9:19 ` [PATCH 5/8] x86-64: add support for remotely triggering the block softirq Jens Axboe
2008-02-07  9:19 ` [PATCH 6/8] ia64: " Jens Axboe
2008-02-07  9:19 ` [PATCH 7/8] kernel: add generic softirq interface for triggering a remote softirq Jens Axboe
2008-02-07  9:19 ` [PATCH 8/8] block: add test code for testing CPU affinity Jens Axboe
2008-02-07 15:16 ` [PATCH 0/8] IO queuing and complete affinity Alan D. Brunelle
2008-02-07 18:25 ` IO queuing and complete affinity with threads (was Re: [PATCH 0/8] IO queuing and complete affinity) Jens Axboe
2008-02-07 20:40   ` Alan D. Brunelle
2008-02-08  7:38   ` Nick Piggin
2008-02-08  7:47     ` Jens Axboe
2008-02-08  7:53       ` Nick Piggin
2008-02-08  7:59         ` Jens Axboe
2008-02-08  8:12           ` Nick Piggin
2008-02-08  8:24             ` Jens Axboe
2008-02-08  8:33               ` Nick Piggin
2008-02-11  5:22           ` David Chinner
2008-02-12  8:28             ` Jeremy Higdon

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