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From: Christoph Lameter <cl@linux.com>
To: Nitin Gupta <ngupta@vflare.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>,
	Minchan Kim <minchan.kim@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Greg KH <greg@kroah.com>,
	Linux Driver Project <devel@driverdev.osuosl.org>,
	linux-mm <linux-mm@kvack.org>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 03/10] Use percpu stats
Date: Mon, 30 Aug 2010 11:20:10 -0500 (CDT)	[thread overview]
Message-ID: <alpine.DEB.2.00.1008301114460.10316@router.home> (raw)
In-Reply-To: <1281374816-904-4-git-send-email-ngupta@vflare.org>

On Mon, 9 Aug 2010, Nitin Gupta wrote:

> -static void zram_stat_inc(u32 *v)
> +static void zram_add_stat(struct zram *zram,
> +			enum zram_stats_index idx, s64 val)
>  {
> -	*v = *v + 1;
> +	struct zram_stats_cpu *stats;
> +
> +	preempt_disable();
> +	stats = __this_cpu_ptr(zram->stats);
> +	u64_stats_update_begin(&stats->syncp);
> +	stats->count[idx] += val;
> +	u64_stats_update_end(&stats->syncp);
> +	preempt_enable();

Maybe do

#define zram_add_stat(zram, index, val)
		this_cpu_add(zram->stats->count[index], val)

instead? It creates an add in a single "atomic" per cpu instruction and
deals with the fallback scenarios for processors that cannot handle 64
bit adds.

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  parent reply	other threads:[~2010-08-30 16:20 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-09 17:26 [PATCH 00/10] zram: various improvements and cleanups Nitin Gupta
2010-08-09 17:26 ` [PATCH 01/10] Replace ioctls with sysfs interface Nitin Gupta
2010-08-09 18:34   ` Pekka Enberg
2010-08-10  3:06     ` Nitin Gupta
2010-08-31 23:06   ` Dave Hansen
2010-08-09 17:26 ` [PATCH 02/10] Remove need for explicit device initialization Nitin Gupta
2010-08-09 18:36   ` Pekka Enberg
2010-08-10  3:38     ` Nitin Gupta
2010-08-09 17:26 ` [PATCH 03/10] Use percpu stats Nitin Gupta
2010-08-09 18:44   ` Pekka Enberg
2010-08-10  4:34   ` Andrew Morton
2010-08-11 16:39     ` Nitin Gupta
2010-08-11 17:18       ` Andrew Morton
2010-08-30 16:20   ` Christoph Lameter [this message]
2010-08-31 20:31     ` Nitin Gupta
2010-08-31 21:28       ` Eric Dumazet
2010-08-31 21:35         ` Christoph Lameter
2010-08-31 21:41           ` Eric Dumazet
2010-09-01 20:05             ` Christoph Lameter
2010-09-01 20:38               ` Eric Dumazet
2010-09-02  0:34                 ` Christoph Lameter
2010-08-31  5:36   ` Anton Blanchard
2010-09-01  3:41     ` Anton Blanchard
2010-09-01  3:51   ` Anton Blanchard
2010-09-17 20:59     ` Andrew Morton
2010-08-09 17:26 ` [PATCH 04/10] Use percpu buffers Nitin Gupta
2010-08-09 18:57   ` Pekka Enberg
2010-08-10  4:47     ` Nitin Gupta
2010-08-10  5:05       ` Pekka Enberg
2010-08-10  5:32         ` Nitin Gupta
2010-08-10  7:36           ` Pekka Enberg
2010-08-09 17:26 ` [PATCH 05/10] Reduce per table entry overhead by 4 bytes Nitin Gupta
2010-08-09 18:59   ` Pekka Enberg
2010-08-10  4:55     ` Nitin Gupta
2010-08-09 17:26 ` [PATCH 06/10] Block discard support Nitin Gupta
2010-08-09 19:03   ` Pekka Enberg
2010-08-10  2:23     ` Jens Axboe
2010-08-10  4:54       ` Nitin Gupta
2010-08-10 15:54         ` Jens Axboe
2010-08-09 17:26 ` [PATCH 07/10] Increase compressed page size threshold Nitin Gupta
2010-08-09 18:32   ` Pekka Enberg
2010-08-09 17:26 ` [PATCH 08/10] Some cleanups Nitin Gupta
2010-08-09 19:02   ` Pekka Enberg
2010-08-09 17:26 ` [PATCH 09/10] Update zram documentation Nitin Gupta
2010-08-09 17:26 ` [PATCH 10/10] Document sysfs entries Nitin Gupta
2010-08-09 19:02   ` Pekka Enberg
2010-08-31 22:37 ` [PATCH 00/10] zram: various improvements and cleanups Greg KH
2010-09-01  3:32 ` Anton Blanchard
2010-09-09 17:24 ` OOM panics with zram Dave Hansen
2010-09-09 19:07   ` [patch -rc] oom: always return a badness score of non-zero for eligible tasks David Rientjes
2010-09-09 19:48     ` Dave Hansen
2010-09-09 21:00       ` David Rientjes
2010-09-09 21:10         ` Dave Hansen
2010-09-09 21:40           ` David Rientjes
2010-10-03 18:41   ` OOM panics with zram Nitin Gupta
2010-10-03 19:27     ` Dave Hansen
2010-10-03 19:40       ` Nitin Gupta
2010-10-04 11:08         ` Ed Tomlinson
2010-10-05 23:43     ` Greg KH
2010-10-06  2:29       ` Nitin Gupta
2010-10-06  2:36         ` Greg KH
2010-10-06  4:30           ` Nitin Gupta
2010-10-06  7:38             ` Pekka Enberg
2010-10-06 14:03               ` Greg KH
2010-10-06 14:16                 ` Pekka Enberg
2010-10-06 14:53                   ` Nitin Gupta
2010-10-06 14:02             ` Greg KH

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