From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: arjanv@redhat.com
Cc: Andrew Morton <akpm@osdl.org>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
Rik van Riel <riel@surriel.com>
Subject: Re: Page aging broken in 2.6
Date: Fri, 26 Dec 2003 20:58:27 +1100 [thread overview]
Message-ID: <1072432706.15477.66.camel@gaston> (raw)
In-Reply-To: <1072430500.5222.2.camel@laptop.fenrus.com>
On Fri, 2003-12-26 at 20:21, Arjan van de Ven wrote:
> > > And we never flush the TLB entry.
> > >
> > > I don't know if x86 (or other archs really using page tables) will
> > > actually set the referenced bit again in the PTE if it's already set
> > > in the TLB, if not, then x86 needs a flush too.
> >
> > x86 needs a flush_tlb_page(), yes.
>
> it does? Are you 100% sure ?
>
> Afaik x86 is very very slow in setting the A and D bits (like 2000 to
> 3000 cycles) *because* it doesn't need a TLB flush....
How does this work ? If x86 always update those bits even when the
TLB copy has them already set, then it will keep writing to the PTEs
on every access... which I doubt it does ;) Or does it snoop accesses
to the PTE to "catch" somebody clearing the bits ?
Ben.
next prev parent reply other threads:[~2003-12-26 9:59 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-26 7:28 Page aging broken in 2.6 Benjamin Herrenschmidt
2003-12-26 7:40 ` Andrew Morton
2003-12-26 9:21 ` Arjan van de Ven
2003-12-26 9:58 ` Benjamin Herrenschmidt [this message]
2003-12-26 19:44 ` Davide Libenzi
2003-12-26 9:33 ` Russell King
2003-12-26 10:07 ` Benjamin Herrenschmidt
2003-12-26 17:59 ` Linus Torvalds
2003-12-26 23:55 ` Benjamin Herrenschmidt
2003-12-27 0:35 ` Linus Torvalds
2003-12-27 0:44 ` Benjamin Herrenschmidt
2003-12-27 0:53 ` Linus Torvalds
2003-12-27 0:59 ` Linus Torvalds
2003-12-27 1:03 ` Benjamin Herrenschmidt
2003-12-27 2:37 ` Andrea Arcangeli
2003-12-27 5:02 ` Benjamin Herrenschmidt
2003-12-27 10:16 ` William Lee Irwin III
2003-12-27 2:47 ` Rik van Riel
2003-12-27 3:00 ` Andrew Morton
2003-12-27 3:31 ` Rik van Riel
2003-12-27 3:54 ` Linus Torvalds
2003-12-27 16:34 ` Martin J. Bligh
2003-12-27 23:07 ` Roger Luethi
2003-12-27 23:55 ` William Lee Irwin III
2003-12-28 11:23 ` Roger Luethi
2003-12-28 16:35 ` William Lee Irwin III
2003-12-28 17:15 ` Roger Luethi
2003-12-28 0:04 ` Andrew Morton
2003-12-28 11:58 ` Roger Luethi
2003-12-27 1:41 ` Andrea Arcangeli
-- strict thread matches above, loose matches on Subject: below --
2003-12-26 10:45 Manfred Spraul
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