From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>,
Linux Memory Management <linux-mm@kvack.org>
Subject: Re: [patch 6/12] mm: remove bad_range
Date: Wed, 23 Nov 2005 13:09:48 +1100 [thread overview]
Message-ID: <4383CF6C.4060001@yahoo.com.au> (raw)
In-Reply-To: <1132662725.6696.45.camel@localhost>
Dave Hansen wrote:
>
> I seem to also remember a case with this bad_range() check was useful
> for zones that don't have their boundaries aligned on a MAX_ORDER
> boundary. Would this change break such a zone? Do we care?
>
Hmm, I guess that would be covered by the:
if (page_to_pfn(page) >= zone->zone_start_pfn + zone->spanned_pages)
return 1;
if (page_to_pfn(page) < zone->zone_start_pfn)
return 1;
checks in bad_range. ISTR some "warning: zone not aligned, kernel
*will* crash" message got printed in that case. I always thought
that zones were supposed to be MAX_ORDER aligned, but I can see how
that restriction might be relaxed with these checks in place.
This commit introduced the change:
http://www.kernel.org/git/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;a=commitdiff;h=d60c9dbc4589766ef5fe88f082052ccd4ecaea59
I think this basically says that architectures who care need to define
CONFIG_HOLES_IN_ZONE and handle this in pfn_valid.
Unless this is a very common requirement and such a solution would have
too much performance cost? Anyone?
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
WARNING: multiple messages have this Message-ID (diff)
From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>,
Linux Memory Management <linux-mm@kvack.org>
Subject: Re: [patch 6/12] mm: remove bad_range
Date: Wed, 23 Nov 2005 13:09:48 +1100 [thread overview]
Message-ID: <4383CF6C.4060001@yahoo.com.au> (raw)
In-Reply-To: <1132662725.6696.45.camel@localhost>
Dave Hansen wrote:
>
> I seem to also remember a case with this bad_range() check was useful
> for zones that don't have their boundaries aligned on a MAX_ORDER
> boundary. Would this change break such a zone? Do we care?
>
Hmm, I guess that would be covered by the:
if (page_to_pfn(page) >= zone->zone_start_pfn + zone->spanned_pages)
return 1;
if (page_to_pfn(page) < zone->zone_start_pfn)
return 1;
checks in bad_range. ISTR some "warning: zone not aligned, kernel
*will* crash" message got printed in that case. I always thought
that zones were supposed to be MAX_ORDER aligned, but I can see how
that restriction might be relaxed with these checks in place.
This commit introduced the change:
http://www.kernel.org/git/?p=linux/kernel/git/torvalds/old-2.6-bkcvs.git;a=commitdiff;h=d60c9dbc4589766ef5fe88f082052ccd4ecaea59
I think this basically says that architectures who care need to define
CONFIG_HOLES_IN_ZONE and handle this in pfn_valid.
Unless this is a very common requirement and such a solution would have
too much performance cost? Anyone?
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
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next prev parent reply other threads:[~2005-11-23 1:07 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-21 11:37 [patch 0/12] mm: optimisations Nick Piggin
2005-11-21 11:41 ` [patch 11/12] mm: page_alloc cleanups Nick Piggin
2005-11-21 12:00 ` [patch 7/12] mm: bad_page opt Nick Piggin
2005-11-21 12:00 ` [patch 8/12] mm: remove pcp low Nick Piggin
2005-11-21 12:07 ` [patch 9/12] mm: page_state opt Nick Piggin
2005-11-22 7:54 ` Andrew Morton
2005-11-22 9:04 ` Nick Piggin
2005-11-22 8:08 ` Andrew Morton
2005-11-21 12:08 ` [patch 12/12] mm: rmap opt Nick Piggin
2005-11-22 19:19 ` Hugh Dickins
2005-11-23 0:07 ` Nick Piggin
2005-11-21 13:07 ` [patch 2/12] mm: pagealloc opt Nick Piggin
2005-11-21 13:08 ` [patch 4/12] mm: set_page_refs opt Nick Piggin
2005-11-21 13:23 ` [patch 1/12] mm: free_pages_and_swap_cache opt Nick Piggin
2005-11-21 13:25 ` [patch 5/12] mm: microopt conditions Nick Piggin
2005-11-21 13:27 ` [patch 10/12] mm: page_state fixes Nick Piggin
2005-11-21 14:29 ` [patch 0/12] mm: optimisations Paul Jackson
2005-11-22 0:26 ` Nick Piggin
2005-11-21 15:10 ` [patch 3/12] mm: release opt Nick Piggin
2005-11-21 15:12 ` [patch 6/12] mm: remove bad_range Nick Piggin
2005-11-22 12:32 ` Dave Hansen
2005-11-23 2:09 ` Nick Piggin [this message]
2005-11-23 2:09 ` Nick Piggin
2005-11-22 8:06 ` [patch 0/12] mm: optimisations Andrew Morton
2005-11-22 10:51 ` Nick Piggin
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