From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Linus Torvalds <torvalds@osdl.org>
Cc: "David S. Miller" <davem@redhat.com>,
wesolows@foobazco.org, willy@debian.org,
Andrea Arcangeli <andrea@suse.de>, Andrew Morton <akpm@osdl.org>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
mingo@elte.hu, bcrl@kvack.org, linux-mm@kvack.org,
Linux Arch list <linux-arch@vger.kernel.org>
Subject: Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE
Date: Wed, 26 May 2004 08:19:24 +1000 [thread overview]
Message-ID: <1085523563.15281.136.camel@gaston> (raw)
In-Reply-To: <Pine.LNX.4.58.0405251504170.9951@ppc970.osdl.org>
On Wed, 2004-05-26 at 08:09, Linus Torvalds wrote:
> But if we don't update the hash tables, how will the TLB entry _ever_ say
> that the page is writable? So we won't take just _one_ extra fault on the
> next write, we'll _keep_ taking them, since the hash tables will continue
> to claim that the page is read-only, even if the linux sw page tables say
> it is writable.
>
> So I think the code needs to invalidate the hash after having updated the
> pte. No?
No, we'll take a hash fault, not a page fault. The hash fault is an asm
fast path, which in this case, will update the HPTE RW permission when
the PTE has PAGE_RW (and will set PAGE_DIRTY again, but that's fine).
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Linus Torvalds <torvalds@osdl.org>
Cc: "David S. Miller" <davem@redhat.com>,
wesolows@foobazco.org, willy@debian.org,
Andrea Arcangeli <andrea@suse.de>, Andrew Morton <akpm@osdl.org>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
mingo@elte.hu, bcrl@kvack.org, linux-mm@kvack.org,
Linux Arch list <linux-arch@vger.kernel.org>
Subject: Re: [PATCH] ppc64: Fix possible race with set_pte on a present PTE
Date: Wed, 26 May 2004 08:19:24 +1000 [thread overview]
Message-ID: <1085523563.15281.136.camel@gaston> (raw)
In-Reply-To: <Pine.LNX.4.58.0405251504170.9951@ppc970.osdl.org>
On Wed, 2004-05-26 at 08:09, Linus Torvalds wrote:
> But if we don't update the hash tables, how will the TLB entry _ever_ say
> that the page is writable? So we won't take just _one_ extra fault on the
> next write, we'll _keep_ taking them, since the hash tables will continue
> to claim that the page is read-only, even if the linux sw page tables say
> it is writable.
>
> So I think the code needs to invalidate the hash after having updated the
> pte. No?
No, we'll take a hash fault, not a page fault. The hash fault is an asm
fast path, which in this case, will update the HPTE RW permission when
the PTE has PAGE_RW (and will set PAGE_DIRTY again, but that's fine).
Ben.
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next prev parent reply other threads:[~2004-05-25 22:23 UTC|newest]
Thread overview: 153+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-24 3:29 [PATCH] ppc64: Fix possible race with set_pte on a present PTE Benjamin Herrenschmidt
2004-05-24 3:47 ` Linus Torvalds
2004-05-24 4:13 ` Benjamin Herrenschmidt
2004-05-24 4:36 ` Linus Torvalds
2004-05-24 4:44 ` Benjamin Herrenschmidt
2004-05-24 5:10 ` Linus Torvalds
2004-05-24 5:10 ` Linus Torvalds
2004-05-24 5:34 ` Benjamin Herrenschmidt
2004-05-24 5:34 ` Benjamin Herrenschmidt
2004-05-24 5:38 ` Benjamin Herrenschmidt
2004-05-24 5:38 ` Benjamin Herrenschmidt
2004-05-24 5:52 ` Benjamin Herrenschmidt
2004-05-24 5:52 ` Benjamin Herrenschmidt
2004-05-24 7:39 ` Ingo Molnar
2004-05-24 7:39 ` Ingo Molnar
2004-05-24 5:39 ` Benjamin Herrenschmidt
2004-05-24 5:39 ` Benjamin Herrenschmidt
2004-05-25 3:43 ` Andrea Arcangeli
2004-05-25 3:43 ` Andrea Arcangeli
2004-05-25 4:00 ` Linus Torvalds
2004-05-25 4:00 ` Linus Torvalds
2004-05-25 4:17 ` Benjamin Herrenschmidt
2004-05-25 4:17 ` Benjamin Herrenschmidt
2004-05-25 4:37 ` Andrea Arcangeli
2004-05-25 4:37 ` Andrea Arcangeli
2004-05-25 4:40 ` Benjamin Herrenschmidt
2004-05-25 4:40 ` Benjamin Herrenschmidt
2004-05-25 4:20 ` Andrea Arcangeli
2004-05-25 4:20 ` Andrea Arcangeli
2004-05-25 4:39 ` Linus Torvalds
2004-05-25 4:39 ` Linus Torvalds
2004-05-25 4:44 ` Linus Torvalds
2004-05-25 4:44 ` Linus Torvalds
2004-05-25 4:59 ` Andrea Arcangeli
2004-05-25 4:59 ` Andrea Arcangeli
2004-05-25 5:09 ` Andrea Arcangeli
2004-05-25 5:09 ` Andrea Arcangeli
2004-05-25 4:50 ` Andrea Arcangeli
2004-05-25 4:50 ` Andrea Arcangeli
2004-05-25 4:59 ` Linus Torvalds
2004-05-25 4:59 ` Linus Torvalds
2004-05-25 4:43 ` David Mosberger
2004-05-25 4:43 ` David Mosberger
2004-05-25 4:53 ` Andrea Arcangeli
2004-05-25 4:53 ` Andrea Arcangeli
2004-05-27 21:56 ` David Mosberger
2004-05-27 21:56 ` David Mosberger
2004-05-27 22:00 ` Benjamin Herrenschmidt
2004-05-27 22:00 ` Benjamin Herrenschmidt
2004-05-27 22:12 ` David Mosberger
2004-05-27 22:12 ` David Mosberger
2004-05-25 11:44 ` Matthew Wilcox
2004-05-25 11:44 ` Matthew Wilcox
2004-05-25 14:48 ` Linus Torvalds
2004-05-25 14:48 ` Linus Torvalds
2004-05-25 15:35 ` Keith M Wesolowski
2004-05-25 15:35 ` Keith M Wesolowski
2004-05-25 16:19 ` Linus Torvalds
2004-05-25 16:19 ` Linus Torvalds
2004-05-25 17:25 ` David S. Miller
2004-05-25 17:25 ` David S. Miller
2004-05-25 17:49 ` Linus Torvalds
2004-05-25 17:49 ` Linus Torvalds
2004-05-25 17:54 ` David S. Miller
2004-05-25 17:54 ` David S. Miller
2004-05-25 18:05 ` Linus Torvalds
2004-05-25 18:05 ` Linus Torvalds
2004-05-25 20:30 ` Linus Torvalds
2004-05-25 20:30 ` Linus Torvalds
2004-05-25 20:35 ` David S. Miller
2004-05-25 20:35 ` David S. Miller
2004-05-25 20:35 ` David S. Miller
2004-05-25 20:49 ` Linus Torvalds
2004-05-25 20:49 ` Linus Torvalds
2004-05-25 20:57 ` David S. Miller
2004-05-25 20:57 ` David S. Miller
2004-05-26 6:20 ` Keith M Wesolowski
2004-05-26 6:20 ` Keith M Wesolowski
2004-05-25 21:40 ` Benjamin Herrenschmidt
2004-05-25 21:40 ` Benjamin Herrenschmidt
2004-05-25 21:54 ` Linus Torvalds
2004-05-25 21:54 ` Linus Torvalds
2004-05-25 22:00 ` Linus Torvalds
2004-05-25 22:00 ` Linus Torvalds
2004-05-25 22:07 ` Benjamin Herrenschmidt
2004-05-25 22:07 ` Benjamin Herrenschmidt
2004-05-25 22:14 ` Linus Torvalds
2004-05-25 22:14 ` Linus Torvalds
2004-05-26 0:21 ` Benjamin Herrenschmidt
2004-05-26 0:21 ` Benjamin Herrenschmidt
2004-05-26 0:50 ` Linus Torvalds
2004-05-26 0:50 ` Linus Torvalds
2004-05-26 3:25 ` Benjamin Herrenschmidt
2004-05-26 3:25 ` Benjamin Herrenschmidt
2004-05-26 4:08 ` Linus Torvalds
2004-05-26 4:08 ` Linus Torvalds
2004-05-26 4:12 ` Benjamin Herrenschmidt
2004-05-26 4:12 ` Benjamin Herrenschmidt
2004-05-26 4:18 ` Benjamin Herrenschmidt
2004-05-26 4:18 ` Benjamin Herrenschmidt
2004-05-26 4:50 ` Linus Torvalds
2004-05-26 4:50 ` Linus Torvalds
2004-05-26 4:49 ` Benjamin Herrenschmidt
2004-05-26 4:49 ` Benjamin Herrenschmidt
2004-05-26 4:28 ` Linus Torvalds
2004-05-26 4:28 ` Linus Torvalds
2004-05-26 4:46 ` Benjamin Herrenschmidt
2004-05-26 4:46 ` Benjamin Herrenschmidt
2004-05-26 4:54 ` Linus Torvalds
2004-05-26 4:54 ` Linus Torvalds
2004-05-26 4:55 ` Benjamin Herrenschmidt
2004-05-26 4:55 ` Benjamin Herrenschmidt
2004-05-26 5:41 ` Benjamin Herrenschmidt
2004-05-26 5:41 ` Benjamin Herrenschmidt
2004-05-26 5:59 ` [PATCH] (signoff) " Benjamin Herrenschmidt
2004-05-26 5:59 ` Benjamin Herrenschmidt
2004-05-26 6:55 ` Benjamin Herrenschmidt
2004-05-26 6:55 ` Benjamin Herrenschmidt
2004-05-26 7:11 ` [PATCH] ppc32 implementation of ptep_set_access_flags Benjamin Herrenschmidt
2004-05-26 15:22 ` Linus Torvalds
2004-05-26 18:49 ` David S. Miller
2004-05-26 21:43 ` Benjamin Herrenschmidt
2004-05-28 1:29 ` David Mosberger
2004-05-25 22:05 ` [PATCH] ppc64: Fix possible race with set_pte on a present PTE Benjamin Herrenschmidt
2004-05-25 22:05 ` Benjamin Herrenschmidt
2004-05-25 22:09 ` Linus Torvalds
2004-05-25 22:09 ` Linus Torvalds
2004-05-25 22:19 ` Benjamin Herrenschmidt [this message]
2004-05-25 22:19 ` Benjamin Herrenschmidt
2004-05-25 22:24 ` Linus Torvalds
2004-05-25 22:24 ` Linus Torvalds
2004-05-25 21:27 ` Andrea Arcangeli
2004-05-25 21:27 ` Andrea Arcangeli
2004-05-25 21:43 ` Linus Torvalds
2004-05-25 21:43 ` Linus Torvalds
2004-05-25 21:55 ` Andrea Arcangeli
2004-05-25 21:55 ` Andrea Arcangeli
2004-05-25 22:01 ` Linus Torvalds
2004-05-25 22:01 ` Linus Torvalds
2004-05-25 22:18 ` Ivan Kokshaysky
2004-05-25 22:18 ` Ivan Kokshaysky
2004-05-25 22:42 ` Andrea Arcangeli
2004-05-25 22:42 ` Andrea Arcangeli
2004-05-26 2:26 ` Linus Torvalds
2004-05-26 2:26 ` Linus Torvalds
2004-05-26 7:06 ` Andrea Arcangeli
2004-05-26 7:06 ` Andrea Arcangeli
2004-05-25 21:44 ` Andrea Arcangeli
2004-05-25 21:44 ` Andrea Arcangeli
-- strict thread matches above, loose matches on Subject: below --
2004-06-01 12:04 Martin Schwidefsky
2004-06-01 12:04 ` Martin Schwidefsky
2004-06-01 12:10 Martin Schwidefsky
2004-06-01 12:10 ` Martin Schwidefsky
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