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From: Tejun Heo <tj@kernel.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Gavin Shan <shangw@linux.vnet.ibm.com>,
	David Miller <davem@davemloft.net>,
	Yinghai Lu <yinghai@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 02/10] mm: bootmem: remove redundant offset check when finally freeing bootmem
Date: Mon, 7 May 2012 11:08:28 -0700	[thread overview]
Message-ID: <20120507180828.GE19417@google.com> (raw)
In-Reply-To: <1336390672-14421-3-git-send-email-hannes@cmpxchg.org>

On Mon, May 07, 2012 at 01:37:44PM +0200, Johannes Weiner wrote:
> When bootmem releases an unaligned BITS_PER_LONG pages chunk of memory
> to the page allocator, it checks the bitmap if there are still
> unreserved pages in the chunk (set bits), but also if the offset in
> the chunk indicates BITS_PER_LONG loop iterations already.
> 
> But since the consulted bitmap is only a one-word-excerpt of the full
> per-node bitmap, there can not be more than BITS_PER_LONG bits set in
> it.  The additional offset check is unnecessary.
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun

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WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj@kernel.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Gavin Shan <shangw@linux.vnet.ibm.com>,
	David Miller <davem@davemloft.net>,
	Yinghai Lu <yinghai@kernel.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 02/10] mm: bootmem: remove redundant offset check when finally freeing bootmem
Date: Mon, 7 May 2012 11:08:28 -0700	[thread overview]
Message-ID: <20120507180828.GE19417@google.com> (raw)
In-Reply-To: <1336390672-14421-3-git-send-email-hannes@cmpxchg.org>

On Mon, May 07, 2012 at 01:37:44PM +0200, Johannes Weiner wrote:
> When bootmem releases an unaligned BITS_PER_LONG pages chunk of memory
> to the page allocator, it checks the bitmap if there are still
> unreserved pages in the chunk (set bits), but also if the offset in
> the chunk indicates BITS_PER_LONG loop iterations already.
> 
> But since the consulted bitmap is only a one-word-excerpt of the full
> per-node bitmap, there can not be more than BITS_PER_LONG bits set in
> it.  The additional offset check is unnecessary.
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun

  reply	other threads:[~2012-05-07 18:08 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-07 11:37 [patch 00/10] (no)bootmem bits for 3.5 Johannes Weiner
2012-05-07 11:37 ` Johannes Weiner
2012-05-07 11:37 ` [patch 01/10] mm: bootmem: fix checking the bitmap when finally freeing bootmem Johannes Weiner
2012-05-07 11:37   ` Johannes Weiner
2012-05-07 18:07   ` Tejun Heo
2012-05-07 18:07     ` Tejun Heo
2012-05-07 11:37 ` [patch 02/10] mm: bootmem: remove redundant offset check " Johannes Weiner
2012-05-07 11:37   ` Johannes Weiner
2012-05-07 18:08   ` Tejun Heo [this message]
2012-05-07 18:08     ` Tejun Heo
2012-05-07 11:37 ` [patch 03/10] mm: bootmem: rename alloc_bootmem_core to alloc_bootmem_bdata Johannes Weiner
2012-05-07 11:37   ` Johannes Weiner
2012-05-07 11:37 ` [patch 04/10] mm: bootmem: split out goal-to-node mapping from goal dropping Johannes Weiner
2012-05-07 11:37   ` Johannes Weiner
2012-05-07 11:37 ` [patch 05/10] mm: bootmem: allocate in order node+goal, goal, node, anywhere Johannes Weiner
2012-05-07 11:37   ` Johannes Weiner
2012-05-07 11:37 ` [patch 06/10] mm: bootmem: unify allocation policy of (non-)panicking node allocations Johannes Weiner
2012-05-07 11:37   ` Johannes Weiner
2012-05-07 11:37 ` [patch 07/10] mm: nobootmem: panic on node-specific allocation failure Johannes Weiner
2012-05-07 11:37   ` Johannes Weiner
2012-05-07 19:17   ` Yinghai Lu
2012-05-07 19:17     ` Yinghai Lu
2012-05-07 11:37 ` [patch 08/10] mm: nobootmem: unify allocation policy of (non-)panicking node allocations Johannes Weiner
2012-05-07 11:37   ` Johannes Weiner
2012-05-07 19:23   ` Yinghai Lu
2012-05-07 19:23     ` Yinghai Lu
2012-05-07 11:37 ` [patch 09/10] mm: bootmem: pass pgdat instead of pgdat->bdata down the stack Johannes Weiner
2012-05-07 11:37   ` Johannes Weiner
2012-05-07 11:37 ` [patch 10/10] mm: remove sparsemem allocation details from the bootmem allocator Johannes Weiner
2012-05-07 11:37   ` Johannes Weiner
2012-05-07 18:19   ` Tejun Heo
2012-05-07 18:19     ` Tejun Heo
2012-05-07 18:21     ` David Miller
2012-05-07 18:21       ` David Miller
2012-05-10 21:44   ` Andrew Morton
2012-05-10 21:44     ` Andrew Morton
2012-05-15 11:47     ` Johannes Weiner
2012-05-15 11:47       ` Johannes Weiner
2012-05-07 20:41 ` [patch 00/10] (no)bootmem bits for 3.5 Sam Ravnborg
2012-05-07 20:41   ` Sam Ravnborg
2012-05-07 22:01   ` Johannes Weiner
2012-05-07 22:01     ` Johannes Weiner
2012-05-08 17:57     ` Sam Ravnborg
2012-05-08 17:57       ` Sam Ravnborg
2012-05-09 17:35       ` Tejun Heo
2012-05-09 17:35         ` Tejun Heo
2012-05-09 17:54         ` Christoph Lameter
2012-05-09 17:54           ` Christoph Lameter
2012-05-09 18:08           ` Tejun Heo
2012-05-09 18:08             ` Tejun Heo

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