From: Andrea Arcangeli <andrea@suse.de>
To: Andrew Morton <akpm@osdl.org>
Cc: hch@infradead.org, hugh@veritas.com, vrajesh@umich.edu,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix
Date: Sun, 4 Apr 2004 01:27:17 +0200 [thread overview]
Message-ID: <20040403232717.GO2307@dualathlon.random> (raw)
In-Reply-To: <20040403120227.398268aa.akpm@osdl.org>
On Sat, Apr 03, 2004 at 12:02:27PM -0800, Andrew Morton wrote:
> It might be better to switch over to address masking in get_user_pages()
> and just dump all the compound page logic. I don't immediately see how the
I'm all for it, this is how the 2.4 get_user_pages deals with bigpages
too, I've never enjoyed the compound thing.
> get_user_pages() caller can subsequently do put_page() against the correct
> pageframe, but I assume you worked that out?
see this patch:
http://www.us.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/2.4.23aa2/9910_shm-largepage-18.gz
it's a two liner fix in follow_page:
@@ -439,6 +457,8 @@ static struct page * follow_page(struct
pmd = pmd_offset(pgd, address);
if (pmd_none(*pmd))
goto out;
+ if (pmd_bigpage(*pmd))
+ return __pmd_page(*pmd) + (address & BIGPAGE_MASK) / PAGE_SIZE;
the BIGPAGE_MASK will never expose anything but the page->private to the
get_user_pages code, and handle_mm_fault takes care of doing the page
faults properly using larepages and pmds if the vma is marked
VM_BIGPAGE.
rawio on largepages has been a must-have feature (especially on >=32G)
for more than one year, definitely no need of compound slowdown for that.
Still I would like to understand what's wrong in Christoph's ppc machine
before dumping the whole compound thing.
WARNING: multiple messages have this Message-ID (diff)
From: Andrea Arcangeli <andrea@suse.de>
To: Andrew Morton <akpm@osdl.org>
Cc: hch@infradead.org, hugh@veritas.com, vrajesh@umich.edu,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix
Date: Sun, 4 Apr 2004 01:27:17 +0200 [thread overview]
Message-ID: <20040403232717.GO2307@dualathlon.random> (raw)
In-Reply-To: <20040403120227.398268aa.akpm@osdl.org>
On Sat, Apr 03, 2004 at 12:02:27PM -0800, Andrew Morton wrote:
> It might be better to switch over to address masking in get_user_pages()
> and just dump all the compound page logic. I don't immediately see how the
I'm all for it, this is how the 2.4 get_user_pages deals with bigpages
too, I've never enjoyed the compound thing.
> get_user_pages() caller can subsequently do put_page() against the correct
> pageframe, but I assume you worked that out?
see this patch:
http://www.us.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/2.4.23aa2/9910_shm-largepage-18.gz
it's a two liner fix in follow_page:
@@ -439,6 +457,8 @@ static struct page * follow_page(struct
pmd = pmd_offset(pgd, address);
if (pmd_none(*pmd))
goto out;
+ if (pmd_bigpage(*pmd))
+ return __pmd_page(*pmd) + (address & BIGPAGE_MASK) / PAGE_SIZE;
the BIGPAGE_MASK will never expose anything but the page->private to the
get_user_pages code, and handle_mm_fault takes care of doing the page
faults properly using larepages and pmds if the vma is marked
VM_BIGPAGE.
rawio on largepages has been a must-have feature (especially on >=32G)
for more than one year, definitely no need of compound slowdown for that.
Still I would like to understand what's wrong in Christoph's ppc machine
before dumping the whole compound thing.
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next prev parent reply other threads:[~2004-04-03 23:27 UTC|newest]
Thread overview: 190+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <Pine.LNX.4.44.0403150527400.28579-100000@localhost.localdomain>
2004-03-21 22:10 ` [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix Rajesh Venkatasubramanian
2004-03-21 22:10 ` Rajesh Venkatasubramanian
2004-03-21 22:12 ` [RFC][PATCH 2/3] Dave & Hugh's objrmap patch Rajesh Venkatasubramanian
2004-03-21 22:12 ` Rajesh Venkatasubramanian
2004-03-21 22:13 ` [RFC][PATCH 3/3] Covert objrmap to use prio_tree Rajesh Venkatasubramanian
2004-03-21 22:13 ` Rajesh Venkatasubramanian
2004-03-21 22:26 ` URL typo Rajesh Venkatasubramanian
2004-03-21 22:26 ` Rajesh Venkatasubramanian
2004-03-22 0:46 ` [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix Andrea Arcangeli
2004-03-22 0:46 ` Andrea Arcangeli
2004-03-22 2:32 ` Rik van Riel
2004-03-22 2:32 ` Rik van Riel
2004-03-22 3:49 ` Rajesh Venkatasubramanian
2004-03-22 3:49 ` Rajesh Venkatasubramanian
2004-03-22 4:02 ` Rik van Riel
2004-03-22 4:02 ` Rik van Riel
2004-03-22 4:21 ` put_super for proc Abhishek Rai
2004-03-22 12:04 ` Maneesh Soni
2004-03-25 22:59 ` [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix Andrea Arcangeli
2004-03-25 22:59 ` Andrea Arcangeli
2004-03-26 4:06 ` Rajesh Venkatasubramanian
2004-03-26 4:06 ` Rajesh Venkatasubramanian
2004-03-26 7:53 ` Andrea Arcangeli
2004-03-26 7:53 ` Andrea Arcangeli
2004-03-26 15:43 ` Rajesh Venkatasubramanian
2004-03-26 15:43 ` Rajesh Venkatasubramanian
2004-03-26 17:58 ` Andrea Arcangeli
2004-03-26 17:58 ` Andrea Arcangeli
2004-03-27 19:51 ` Rajesh Venkatasubramanian
2004-03-27 19:51 ` Rajesh Venkatasubramanian
2004-03-29 17:22 ` Andrea Arcangeli
2004-03-29 17:22 ` Andrea Arcangeli
2004-03-29 17:50 ` Rajesh Venkatasubramanian
2004-03-29 17:50 ` Rajesh Venkatasubramanian
2004-03-29 18:01 ` Andrea Arcangeli
2004-03-29 18:01 ` Andrea Arcangeli
2004-03-29 20:40 ` Andrew Morton
2004-03-29 20:40 ` Andrew Morton
2004-03-29 22:24 ` Hugh Dickins
2004-03-29 22:24 ` Hugh Dickins
2004-03-29 22:54 ` Andrea Arcangeli
2004-03-29 22:54 ` Andrea Arcangeli
2004-03-29 23:08 ` William Lee Irwin III
2004-03-29 23:08 ` William Lee Irwin III
2004-03-29 22:39 ` Andrea Arcangeli
2004-03-29 22:39 ` Andrea Arcangeli
2004-03-29 22:42 ` Andrew Morton
2004-03-29 22:42 ` Andrew Morton
2004-03-31 15:07 ` Andrea Arcangeli
2004-03-31 15:07 ` Andrea Arcangeli
2004-03-31 15:26 ` Andrea Arcangeli
2004-03-31 15:26 ` Andrea Arcangeli
2004-03-31 16:45 ` Hugh Dickins
2004-03-31 16:45 ` Hugh Dickins
2004-03-31 17:28 ` Andrea Arcangeli
2004-03-31 17:28 ` Andrea Arcangeli
2004-04-01 0:45 ` Andrea Arcangeli
2004-04-01 0:45 ` Andrea Arcangeli
2004-04-01 1:22 ` Andrew Morton
2004-04-01 1:22 ` Andrew Morton
2004-04-01 1:26 ` Andrea Arcangeli
2004-04-01 1:26 ` Andrea Arcangeli
2004-04-01 1:51 ` Andrew Morton
2004-04-01 1:51 ` Andrew Morton
2004-04-01 2:01 ` Andrea Arcangeli
2004-04-01 2:01 ` Andrea Arcangeli
2004-04-01 5:05 ` Hugh Dickins
2004-04-01 5:05 ` Hugh Dickins
2004-04-01 13:35 ` Andrea Arcangeli
2004-04-01 13:35 ` Andrea Arcangeli
2004-04-01 15:09 ` Andrea Arcangeli
2004-04-01 15:09 ` Andrea Arcangeli
2004-04-01 15:15 ` Andrea Arcangeli
2004-04-01 15:15 ` Andrea Arcangeli
2004-04-02 0:15 ` Andrea Arcangeli
2004-04-02 0:15 ` Andrea Arcangeli
2004-04-02 0:52 ` Andrew Morton
2004-04-02 0:52 ` Andrew Morton
2004-04-02 1:06 ` Andrea Arcangeli
2004-04-02 1:06 ` Andrea Arcangeli
2004-04-02 1:03 ` Hugh Dickins
2004-04-02 1:03 ` Hugh Dickins
2004-04-02 1:16 ` Andrea Arcangeli
2004-04-02 1:16 ` Andrea Arcangeli
2004-04-02 1:36 ` Andrew Morton
2004-04-02 1:36 ` Andrew Morton
2004-04-02 2:00 ` Andrea Arcangeli
2004-04-02 2:00 ` Andrea Arcangeli
2004-04-02 2:08 ` Andrew Morton
2004-04-02 2:08 ` Andrew Morton
2004-04-02 2:22 ` Andrea Arcangeli
2004-04-02 2:22 ` Andrea Arcangeli
2004-04-02 6:05 ` Christoph Hellwig
2004-04-02 6:05 ` Christoph Hellwig
2004-04-02 7:07 ` Paul Mackerras
2004-04-02 7:07 ` Paul Mackerras
2004-04-02 7:11 ` Christoph Hellwig
2004-04-02 7:11 ` Christoph Hellwig
2004-04-02 15:28 ` Andrea Arcangeli
2004-04-02 15:28 ` Andrea Arcangeli
2004-04-02 15:22 ` Andrea Arcangeli
2004-04-02 15:22 ` Andrea Arcangeli
2004-04-02 15:27 ` Christoph Hellwig
2004-04-02 15:27 ` Christoph Hellwig
2004-04-02 15:38 ` Andrea Arcangeli
2004-04-02 15:38 ` Andrea Arcangeli
2004-04-02 15:45 ` Andrea Arcangeli
2004-04-02 15:45 ` Andrea Arcangeli
2004-04-02 9:43 ` Christoph Hellwig
2004-04-02 9:43 ` Christoph Hellwig
2004-04-02 10:21 ` Marc-Christian Petersen
2004-04-02 10:21 ` Marc-Christian Petersen
2004-04-02 10:55 ` Hugh Dickins
2004-04-02 10:55 ` Hugh Dickins
2004-04-02 16:46 ` Andrea Arcangeli
2004-04-02 16:46 ` Andrea Arcangeli
2004-04-02 18:59 ` Christoph Hellwig
2004-04-02 18:59 ` Christoph Hellwig
2004-04-02 19:29 ` Andrea Arcangeli
2004-04-02 19:29 ` Andrea Arcangeli
2004-04-02 19:54 ` Christoph Hellwig
2004-04-02 19:54 ` Christoph Hellwig
2004-04-02 20:35 ` Andrea Arcangeli
2004-04-02 20:35 ` Andrea Arcangeli
2004-04-03 8:40 ` Christoph Hellwig
2004-04-03 8:40 ` Christoph Hellwig
2004-04-03 15:20 ` Andrea Arcangeli
2004-04-03 15:20 ` Andrea Arcangeli
2004-04-03 15:59 ` Andrea Arcangeli
2004-04-03 15:59 ` Andrea Arcangeli
2004-04-03 17:02 ` Andrea Arcangeli
2004-04-03 17:02 ` Andrea Arcangeli
2004-04-05 9:59 ` Christoph Hellwig
2004-04-05 9:59 ` Christoph Hellwig
2004-04-05 12:11 ` Christoph Hellwig
2004-04-05 12:11 ` Christoph Hellwig
2004-04-05 16:08 ` Andrea Arcangeli
2004-04-05 16:08 ` Andrea Arcangeli
2004-04-06 4:22 ` Andrea Arcangeli
2004-04-06 4:22 ` Andrea Arcangeli
2004-04-06 4:43 ` Andrew Morton
2004-04-06 4:43 ` Andrew Morton
2004-04-06 5:14 ` Christoph Hellwig
2004-04-06 5:14 ` Christoph Hellwig
2004-04-06 21:54 ` Andrea Arcangeli
2004-04-06 21:54 ` Andrea Arcangeli
2004-04-07 1:39 ` Nathan Scott
2004-04-07 1:39 ` Nathan Scott
2004-04-06 5:16 ` Christoph Hellwig
2004-04-06 5:16 ` Christoph Hellwig
2004-04-06 16:01 ` Andrea Arcangeli
2004-04-06 16:01 ` Andrea Arcangeli
2004-04-07 1:33 ` Nathan Scott
2004-04-07 1:33 ` Nathan Scott
2004-04-03 17:40 ` Andrea Arcangeli
2004-04-03 17:40 ` Andrea Arcangeli
2004-04-03 20:02 ` Andrew Morton
2004-04-03 20:02 ` Andrew Morton
2004-04-03 23:27 ` Andrea Arcangeli [this message]
2004-04-03 23:27 ` Andrea Arcangeli
2004-04-03 23:46 ` Andrew Morton
2004-04-03 23:46 ` Andrew Morton
2004-04-04 0:40 ` Andrea Arcangeli
2004-04-04 0:40 ` Andrea Arcangeli
2004-04-08 19:10 ` Bill Davidsen
2004-04-20 22:29 ` Pavel Machek
2004-04-02 20:13 ` Pavel Machek
2004-04-02 20:13 ` Pavel Machek
2004-04-02 21:42 ` Andrea Arcangeli
2004-04-02 21:42 ` Andrea Arcangeli
2004-04-02 21:45 ` Pavel Machek
2004-04-02 21:45 ` Pavel Machek
2004-04-02 21:49 ` Andrea Arcangeli
2004-04-02 21:49 ` Andrea Arcangeli
2004-03-29 18:12 ` Hugh Dickins
2004-03-29 18:12 ` Hugh Dickins
2004-03-29 18:20 ` Andrea Arcangeli
2004-03-29 18:20 ` Andrea Arcangeli
2004-03-29 18:38 ` Christoph Hellwig
2004-03-29 18:38 ` Christoph Hellwig
2004-03-29 21:30 ` 2.6.5-rc2-aa5 Rajesh Venkatasubramanian
2004-03-29 22:50 ` 2.6.5-rc2-aa5 Andrea Arcangeli
2004-04-05 3:14 ` [RFC][PATCH 1/3] radix priority search tree - objrmap complexity fix Rajesh Venkatasubramanian
2004-04-05 3:14 ` Rajesh Venkatasubramanian
2004-04-05 4:42 ` Andrea Arcangeli
2004-04-05 4:42 ` Andrea Arcangeli
2004-03-26 12:26 ` William Lee Irwin III
2004-03-26 12:26 ` William Lee Irwin III
2004-03-26 19:18 ` Andrea Arcangeli
2004-03-26 19:18 ` Andrea Arcangeli
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