From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Mike Yoknis <mike.yoknis@hp.com>,
mingo@redhat.com, akpm@linux-foundation.org,
linux-arch@vger.kernel.org, mmarek@suse.cz, tglx@linutronix.de,
hpa@zytor.com, arnd@arndb.de, sam@ravnborg.org,
minchan@kernel.org, kamezawa.hiroyu@jp.fujitsu.com,
mhocko@suse.cz, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: memmap_init_zone() performance improvement
Date: Tue, 30 Oct 2012 08:14:22 -0700 [thread overview]
Message-ID: <508FEECE.2070402@linux.vnet.ibm.com> (raw)
In-Reply-To: <20121020082858.GA2698@suse.de>
On 10/20/2012 01:29 AM, Mel Gorman wrote:
> I'm travelling at the moment so apologies that I have not followed up on
> this. My problem is still the same with the patch - it changes more
> headers than is necessary and it is sparsemem specific. At minimum, try
> the suggestion of
>
> if (!early_pfn_valid(pfn)) {
> pfn = ALIGN(pfn + MAX_ORDER_NR_PAGES, MAX_ORDER_NR_PAGES) - 1;
> continue;
> }
Sorry I didn't catch this until v2...
Is that ALIGN() correct? If pfn=3, then it would expand to:
(3+MAX_ORDER_NR_PAGES+MAX_ORDER_NR_PAGES-1) & ~(MAX_ORDER_NR_PAGES-1)
You would end up skipping the current MAX_ORDER_NR_PAGES area, and then
one _extra_ because ALIGN() aligns up, and you're adding
MAX_ORDER_NR_PAGES too. It doesn't matter unless you run in to a
!early_valid_pfn() in the middle of a MAX_ORDER area, I guess.
I think this would work, plus be a bit smaller:
pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES) - 1;
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WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave@linux.vnet.ibm.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Mike Yoknis <mike.yoknis@hp.com>,
mingo@redhat.com, akpm@linux-foundation.org,
linux-arch@vger.kernel.org, mmarek@suse.cz, tglx@linutronix.de,
hpa@zytor.com, arnd@arndb.de, sam@ravnborg.org,
minchan@kernel.org, kamezawa.hiroyu@jp.fujitsu.com,
mhocko@suse.cz, linux-kbuild@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: memmap_init_zone() performance improvement
Date: Tue, 30 Oct 2012 08:14:22 -0700 [thread overview]
Message-ID: <508FEECE.2070402@linux.vnet.ibm.com> (raw)
Message-ID: <20121030151422.Kjr-z8yA43MkVO6BZHbFIsHtK8_myEv-RN5tYSGMer8@z> (raw)
In-Reply-To: <20121020082858.GA2698@suse.de>
On 10/20/2012 01:29 AM, Mel Gorman wrote:
> I'm travelling at the moment so apologies that I have not followed up on
> this. My problem is still the same with the patch - it changes more
> headers than is necessary and it is sparsemem specific. At minimum, try
> the suggestion of
>
> if (!early_pfn_valid(pfn)) {
> pfn = ALIGN(pfn + MAX_ORDER_NR_PAGES, MAX_ORDER_NR_PAGES) - 1;
> continue;
> }
Sorry I didn't catch this until v2...
Is that ALIGN() correct? If pfn=3, then it would expand to:
(3+MAX_ORDER_NR_PAGES+MAX_ORDER_NR_PAGES-1) & ~(MAX_ORDER_NR_PAGES-1)
You would end up skipping the current MAX_ORDER_NR_PAGES area, and then
one _extra_ because ALIGN() aligns up, and you're adding
MAX_ORDER_NR_PAGES too. It doesn't matter unless you run in to a
!early_valid_pfn() in the middle of a MAX_ORDER area, I guess.
I think this would work, plus be a bit smaller:
pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES) - 1;
next prev parent reply other threads:[~2012-10-30 15:14 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-03 14:56 [PATCH] mm: memmap_init_zone() performance improvement Mike Yoknis
2012-10-06 23:59 ` Ni zhan Chen
2012-10-06 23:59 ` Ni zhan Chen
2012-10-08 15:16 ` Mel Gorman
2012-10-08 15:16 ` Mel Gorman
2012-10-09 0:42 ` Ni zhan Chen
2012-10-09 0:42 ` Ni zhan Chen
2012-10-09 14:56 ` Mike Yoknis
2012-10-09 14:56 ` Mike Yoknis
2012-10-19 19:53 ` Mike Yoknis
2012-10-19 19:53 ` Mike Yoknis
2012-10-20 8:29 ` Mel Gorman
2012-10-20 8:29 ` Mel Gorman
2012-10-24 15:47 ` Mike Yoknis
2012-10-24 15:47 ` Mike Yoknis
2012-10-25 9:44 ` Mel Gorman
2012-10-25 9:44 ` Mel Gorman
2012-10-26 22:47 ` [PATCH v2] " Mike Yoknis
2012-10-26 22:47 ` Mike Yoknis
2012-10-30 22:31 ` Andrew Morton
2012-10-30 22:31 ` Andrew Morton
2012-10-30 15:14 ` Dave Hansen [this message]
2012-10-30 15:14 ` [PATCH] " Dave Hansen
2012-11-06 16:03 ` Mike Yoknis
2012-11-06 16:03 ` Mike Yoknis
2012-12-18 23:03 ` Andrew Morton
2012-12-18 23:03 ` Andrew Morton
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