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From: Andrew Morton <akpm@linux-foundation.org>
To: Izik Eidus <ieidus@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	linux-mm@kvack.org, avi@redhat.com, aarcange@redhat.com,
	chrisw@redhat.com, mtosatti@redhat.com, hugh@veritas.com,
	kamezawa.hiroyu@jp.fujitsu.com, ieidus@redhat.com
Subject: Re: [PATCH 3/4] add replace_page(): change the page pte is pointing to.
Date: Tue, 14 Apr 2009 15:09:25 -0700	[thread overview]
Message-ID: <20090414150925.58b464f7.akpm@linux-foundation.org> (raw)
In-Reply-To: <1239249521-5013-4-git-send-email-ieidus@redhat.com>

On Thu,  9 Apr 2009 06:58:40 +0300
Izik Eidus <ieidus@redhat.com> wrote:

> replace_page() allow changing the mapping of pte from one physical page
> into diffrent physical page.

At a high level, this is very similar to what page migration does.  Yet
this implementation shares nothing with the page migration code.

Can this situation be improved?

> this function is working by removing oldpage from the rmap and calling
> put_page on it, and by setting the pte to point into newpage and by
> inserting it to the rmap using page_add_file_rmap().
> 
> note: newpage must be non anonymous page, the reason for this is:
> replace_page() is built to allow mapping one page into more than one
> virtual addresses, the mapping of this page can happen in diffrent
> offsets inside each vma, and therefore we cannot trust the page->index
> anymore.
> 
> the side effect of this issue is that newpage cannot be anything but
> kernel allocated page that is not swappable.
> 


WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Izik Eidus <ieidus@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	linux-mm@kvack.org, avi@redhat.com, aarcange@redhat.com,
	chrisw@redhat.com, mtosatti@redhat.com, hugh@veritas.com,
	kamezawa.hiroyu@jp.fujitsu.com, ieidus@redhat.com
Subject: Re: [PATCH 3/4] add replace_page(): change the page pte is pointing to.
Date: Tue, 14 Apr 2009 15:09:25 -0700	[thread overview]
Message-ID: <20090414150925.58b464f7.akpm@linux-foundation.org> (raw)
In-Reply-To: <1239249521-5013-4-git-send-email-ieidus@redhat.com>

On Thu,  9 Apr 2009 06:58:40 +0300
Izik Eidus <ieidus@redhat.com> wrote:

> replace_page() allow changing the mapping of pte from one physical page
> into diffrent physical page.

At a high level, this is very similar to what page migration does.  Yet
this implementation shares nothing with the page migration code.

Can this situation be improved?

> this function is working by removing oldpage from the rmap and calling
> put_page on it, and by setting the pte to point into newpage and by
> inserting it to the rmap using page_add_file_rmap().
> 
> note: newpage must be non anonymous page, the reason for this is:
> replace_page() is built to allow mapping one page into more than one
> virtual addresses, the mapping of this page can happen in diffrent
> offsets inside each vma, and therefore we cannot trust the page->index
> anymore.
> 
> the side effect of this issue is that newpage cannot be anything but
> kernel allocated page that is not swappable.
> 

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Izik Eidus <ieidus@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	linux-mm@kvack.org, avi@redhat.com, aarcange@redhat.com,
	chrisw@redhat.com, mtosatti@redhat.com, hugh@veritas.com,
	kamezawa.hiroyu@jp.fujitsu.com
Subject: Re: [PATCH 3/4] add replace_page(): change the page pte is pointing to.
Date: Tue, 14 Apr 2009 15:09:25 -0700	[thread overview]
Message-ID: <20090414150925.58b464f7.akpm@linux-foundation.org> (raw)
In-Reply-To: <1239249521-5013-4-git-send-email-ieidus@redhat.com>

On Thu,  9 Apr 2009 06:58:40 +0300
Izik Eidus <ieidus@redhat.com> wrote:

> replace_page() allow changing the mapping of pte from one physical page
> into diffrent physical page.

At a high level, this is very similar to what page migration does.  Yet
this implementation shares nothing with the page migration code.

Can this situation be improved?

> this function is working by removing oldpage from the rmap and calling
> put_page on it, and by setting the pte to point into newpage and by
> inserting it to the rmap using page_add_file_rmap().
> 
> note: newpage must be non anonymous page, the reason for this is:
> replace_page() is built to allow mapping one page into more than one
> virtual addresses, the mapping of this page can happen in diffrent
> offsets inside each vma, and therefore we cannot trust the page->index
> anymore.
> 
> the side effect of this issue is that newpage cannot be anything but
> kernel allocated page that is not swappable.
> 

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  parent reply	other threads:[~2009-04-14 22:15 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-09  3:58 [PATCH 0/4] ksm - dynamic page sharing driver for linux v3 Izik Eidus
2009-04-09  3:58 ` Izik Eidus
2009-04-09  3:58 ` [PATCH 1/4] MMU_NOTIFIERS: add set_pte_at_notify() Izik Eidus
2009-04-09  3:58   ` Izik Eidus
2009-04-09  3:58   ` [PATCH 2/4] add page_wrprotect(): write protecting page Izik Eidus
2009-04-09  3:58     ` Izik Eidus
2009-04-09  3:58     ` [PATCH 3/4] add replace_page(): change the page pte is pointing to Izik Eidus
2009-04-09  3:58       ` Izik Eidus
2009-04-09  3:58       ` [PATCH 4/4] add ksm kernel shared memory driver Izik Eidus
2009-04-09  3:58         ` Izik Eidus
2009-04-14 22:09         ` Andrew Morton
2009-04-14 22:09           ` Andrew Morton
2009-04-14 22:09           ` Andrew Morton
2009-04-15 22:37           ` Izik Eidus
2009-04-15 22:37             ` Izik Eidus
2009-04-15 22:50             ` Andrew Morton
2009-04-15 22:50               ` Andrew Morton
2009-04-15 23:21               ` Andrea Arcangeli
2009-04-15 23:21                 ` Andrea Arcangeli
2009-04-16  0:43           ` Jeremy Fitzhardinge
2009-04-16  0:43             ` Jeremy Fitzhardinge
2009-04-16  0:57             ` Izik Eidus
2009-04-16  0:57               ` Izik Eidus
2009-04-16 11:39             ` Andrea Arcangeli
2009-04-16 11:39               ` Andrea Arcangeli
2009-04-16 16:08               ` Jeremy Fitzhardinge
2009-04-16 16:08                 ` Jeremy Fitzhardinge
2009-04-18 14:58           ` Andrea Arcangeli
2009-04-18 14:58             ` Andrea Arcangeli
2009-04-14 22:09       ` Andrew Morton [this message]
2009-04-14 22:09         ` [PATCH 3/4] add replace_page(): change the page pte is pointing to Andrew Morton
2009-04-14 22:09         ` Andrew Morton
2009-04-15 11:25         ` Andrea Arcangeli
2009-04-15 11:25           ` Andrea Arcangeli
2009-04-15 22:48           ` Izik Eidus
2009-04-15 22:48             ` Izik Eidus
2009-04-14 22:09 ` [PATCH 0/4] ksm - dynamic page sharing driver for linux v3 Andrew Morton
2009-04-14 22:09   ` Andrew Morton
2009-04-14 22:09   ` Andrew Morton
2009-04-16 17:55   ` Nick Piggin
2009-04-16 17:55     ` Nick Piggin
2009-04-16 18:25     ` Izik Eidus
2009-04-16 18:25       ` Izik Eidus
2009-04-17  7:08     ` Jared Hulbert
2009-04-17  7:08       ` Jared Hulbert
2009-04-21  2:59       ` Nick Piggin
2009-04-21  2:59         ` Nick Piggin
  -- strict thread matches above, loose matches on Subject: below --
2009-04-04 14:35 [PATCH 0/4] ksm - dynamic page sharing driver for linux v2 Izik Eidus
2009-04-04 14:35 ` [PATCH 1/4] MMU_NOTIFIERS: add set_pte_at_notify() Izik Eidus
2009-04-04 14:35   ` [PATCH 2/4] add page_wrprotect(): write protecting page Izik Eidus
2009-04-04 14:35     ` [PATCH 3/4] add replace_page(): change the page pte is pointing to Izik Eidus
2009-04-04 14:35       ` Izik Eidus
2009-03-30 23:59 [PATCH 0/4] ksm - dynamic page sharing driver for linux Izik Eidus
2009-03-30 23:59 ` [PATCH 1/4] MMU_NOTIFIERS: add set_pte_at_notify() Izik Eidus
2009-03-30 23:59   ` [PATCH 2/4] add page_wrprotect(): write protecting page Izik Eidus
2009-03-30 23:59     ` [PATCH 3/4] add replace_page(): change the page pte is pointing to Izik Eidus
2009-03-30 23:59       ` Izik Eidus

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