From: ebiederm@xmission.com (Eric W. Biederman)
To: suparna@in.ibm.com
Cc: linux-kernel@vger.kernel.org, marcelo@brutus.conectiva.com.br,
linux-mm@kvack.org
Subject: Re: [PATCH]Fix: Init page count for all pages during higher order allocs
Date: 29 Apr 2002 11:40:21 -0600 [thread overview]
Message-ID: <m1r8ky1jzu.fsf@frodo.biederman.org> (raw)
In-Reply-To: <20020429202446.A2326@in.ibm.com>
Suparna Bhattacharya <suparna@in.ibm.com> writes:
> The call to set_page_count(page, 1) in page_alloc.c appears to happen
> only for the first page, for order 1 and higher allocations.
> This leaves the count for the rest of the pages in that block
> uninitialised.
Actually it should be zero.
This is deliberate because high order pages should not be referenced by
their partial pages. It might make sense to add a PG_large flag and
then in the immediately following struct page add a pointer to the next
page, so you can identify these pages by inspection. Doing something
similar to the PG_skip flag.
Beyond that I get nervous, that people will treat it as endorsement of
doing a high order continuous allocation and then fragmenting the page.
Eric
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next parent reply other threads:[~2002-04-29 17:40 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20020429202446.A2326@in.ibm.com>
2002-04-29 17:40 ` Eric W. Biederman [this message]
2002-04-30 5:31 ` Suparna Bhattacharya
2002-04-30 14:05 ` Eric W. Biederman
2002-04-30 15:08 ` Suparna Bhattacharya
2002-04-30 19:47 ` Andrew Morton
2002-05-02 8:54 ` Suparna Bhattacharya
2002-05-02 13:08 ` Hugh Dickins
2002-05-02 21:13 ` Daniel Phillips
2002-05-03 12:24 ` Suparna Bhattacharya
2002-05-03 13:46 ` Hugh Dickins
2002-05-07 10:11 ` Suparna Bhattacharya
2002-05-07 7:34 ` Bharata B Rao
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