From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Izik Eidus <ieidus@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-mm@kvack.org, avi@redhat.com, chrisw@redhat.com,
mtosatti@redhat.com, hugh@veritas.com,
kamezawa.hiroyu@jp.fujitsu.com
Subject: Re: [PATCH 4/4] add ksm kernel shared memory driver.
Date: Thu, 16 Apr 2009 09:08:42 -0700 [thread overview]
Message-ID: <49E7580A.1080903@goop.org> (raw)
In-Reply-To: <20090416113931.GF4524@random.random>
Andrea Arcangeli wrote:
> On Wed, Apr 15, 2009 at 05:43:03PM -0700, Jeremy Fitzhardinge wrote:
>
>> Shouldn't that be kmap_atomic's job anyway? Otherwise it would be hard to
>>
>
> No because those are full noops in no-highmem kernels. I commented in
> other email why I think it's safe thanks to the wrprotect + smp tlb
> flush of the userland PTE.
>
I think Andrew's query was about data cache synchronization in
architectures with virtually indexed d-cache. On x86 it's a non-issue,
but on architectures for which it is an issue, I assume kmap_atomic does
any necessary cache flushes, as it does tlb flushes on x86 (which may be
none at all, if no mapping actually happens).
J
WARNING: multiple messages have this Message-ID (diff)
From: Jeremy Fitzhardinge <jeremy@goop.org>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Izik Eidus <ieidus@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-mm@kvack.org, avi@redhat.com, chrisw@redhat.com,
mtosatti@redhat.com, hugh@veritas.com,
kamezawa.hiroyu@jp.fujitsu.com
Subject: Re: [PATCH 4/4] add ksm kernel shared memory driver.
Date: Thu, 16 Apr 2009 09:08:42 -0700 [thread overview]
Message-ID: <49E7580A.1080903@goop.org> (raw)
In-Reply-To: <20090416113931.GF4524@random.random>
Andrea Arcangeli wrote:
> On Wed, Apr 15, 2009 at 05:43:03PM -0700, Jeremy Fitzhardinge wrote:
>
>> Shouldn't that be kmap_atomic's job anyway? Otherwise it would be hard to
>>
>
> No because those are full noops in no-highmem kernels. I commented in
> other email why I think it's safe thanks to the wrprotect + smp tlb
> flush of the userland PTE.
>
I think Andrew's query was about data cache synchronization in
architectures with virtually indexed d-cache. On x86 it's a non-issue,
but on architectures for which it is an issue, I assume kmap_atomic does
any necessary cache flushes, as it does tlb flushes on x86 (which may be
none at all, if no mapping actually happens).
J
--
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>
next prev parent reply other threads:[~2009-04-16 16:09 UTC|newest]
Thread overview: 106+ 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 [this message]
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 ` [PATCH 3/4] add replace_page(): change the page pte is pointing to Andrew Morton
2009-04-14 22:09 ` 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 ` [PATCH 4/4] add ksm kernel shared memory driver Izik Eidus
2009-04-04 14:35 ` Izik Eidus
2009-04-06 9:13 ` Andrey Panin
2009-04-06 9:13 ` Andrey Panin
2009-04-06 10:58 ` Izik Eidus
2009-04-06 10:58 ` Izik Eidus
2009-04-06 10:58 ` 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 ` [PATCH 4/4] add ksm kernel shared memory driver Izik Eidus
2009-03-30 23:59 ` Izik Eidus
2009-03-31 2:12 ` Anthony Liguori
2009-03-31 2:12 ` Anthony Liguori
2009-03-31 12:24 ` Izik Eidus
2009-03-31 12:24 ` Izik Eidus
2009-03-31 13:31 ` Anthony Liguori
2009-03-31 13:31 ` Anthony Liguori
2009-03-31 14:25 ` Andrea Arcangeli
2009-03-31 14:25 ` Andrea Arcangeli
2009-03-31 14:37 ` Anthony Liguori
2009-03-31 14:37 ` Anthony Liguori
2009-03-31 15:02 ` Andrea Arcangeli
2009-03-31 15:02 ` Andrea Arcangeli
2009-03-31 15:09 ` Anthony Liguori
2009-03-31 15:09 ` Anthony Liguori
2009-03-31 15:18 ` Andrea Arcangeli
2009-03-31 15:18 ` Andrea Arcangeli
2009-03-31 15:54 ` Anthony Liguori
2009-03-31 15:54 ` Anthony Liguori
2009-03-31 16:25 ` Andrea Arcangeli
2009-03-31 16:25 ` Andrea Arcangeli
2009-03-31 16:51 ` Anthony Liguori
2009-03-31 16:51 ` Anthony Liguori
2009-03-31 17:11 ` Andrea Arcangeli
2009-03-31 17:11 ` Andrea Arcangeli
2009-04-01 22:54 ` Izik Eidus
2009-04-01 22:54 ` Izik Eidus
2009-04-02 0:31 ` Anthony Liguori
2009-04-02 0:31 ` Anthony Liguori
2009-04-02 0:48 ` Chris Wright
2009-04-02 0:48 ` Chris Wright
2009-04-02 1:22 ` Chris Wright
2009-04-02 1:22 ` Chris Wright
2009-04-02 2:36 ` Anthony Liguori
2009-04-02 2:36 ` Anthony Liguori
2009-04-02 7:24 ` Avi Kivity
2009-04-02 7:24 ` Avi Kivity
2009-04-02 9:38 ` Andrea Arcangeli
2009-04-02 9:38 ` Andrea Arcangeli
2009-04-02 11:23 ` Izik Eidus
2009-04-02 11:23 ` Izik Eidus
2009-03-31 2:15 ` KAMEZAWA Hiroyuki
2009-03-31 2:15 ` KAMEZAWA Hiroyuki
2009-03-31 12:21 ` Izik Eidus
2009-03-31 12:21 ` Izik Eidus
2009-03-31 23:57 ` KAMEZAWA Hiroyuki
2009-03-31 23:57 ` KAMEZAWA Hiroyuki
2009-04-01 17:28 ` Izik Eidus
2009-04-01 17:28 ` Izik Eidus
2009-03-31 20:52 ` Andrea Arcangeli
2009-03-31 20:52 ` Andrea Arcangeli
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=49E7580A.1080903@goop.org \
--to=jeremy@goop.org \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=avi@redhat.com \
--cc=chrisw@redhat.com \
--cc=hugh@veritas.com \
--cc=ieidus@redhat.com \
--cc=kamezawa.hiroyu@jp.fujitsu.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mtosatti@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.