From: torvalds@transmeta.com (Linus Torvalds)
To: linux-kernel@vger.kernel.org
Subject: Re: Hashing and directories
Date: 7 Mar 2001 10:21:56 -0800 [thread overview]
Message-ID: <985u84$2ku$1@penguin.transmeta.com> (raw)
In-Reply-To: <000201c0a71f$3a48fae0$5517fea9@local> <20010307171020.A10607@pcep-jamie.cern.ch> <003701c0a722$f6b02700$5517fea9@local>
In article <003701c0a722$f6b02700$5517fea9@local>,
Manfred Spraul <manfred@colorfullife.com> wrote:
>
>exec_mmap currenly avoids mm_alloc()/activate_mm()/mm_drop() for single
>threaded apps, and that would become impossible.
>I'm not sure how expensive these calls are.
They aren't that expensive: activate_mm() needs to flush the TLB, but we
do that anyway in the re-use case too, so on the whole the expense is
limited to having to do the extra allocation.
That expense might be at least partially offset by being able to do some
things more simply - right now the mm re-use case actually has to be
more careful than I really like for security and protection reasons, for
example. We've had bugs in this area before - simplifying it would be
nice. And it also gets rid of the special cases.
I don't think the patches to do this should be all that huge, but who
knows? It's not a trivial part of the kernel.
Linus
next prev parent reply other threads:[~2001-03-07 18:23 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-03-07 15:56 Hashing and directories Manfred Spraul
2001-03-07 16:10 ` Jamie Lokier
2001-03-07 16:23 ` Manfred Spraul
2001-03-07 18:21 ` Linus Torvalds [this message]
-- strict thread matches above, loose matches on Subject: below --
2001-02-22 23:08 Bill Crawford
2000-01-01 2:02 ` Pavel Machek
2001-03-01 20:54 ` Alexander Viro
2001-03-01 21:05 ` H. Peter Anvin
2001-03-01 21:13 ` Alexander Viro
2001-03-01 21:24 ` H. Peter Anvin
2001-03-02 9:04 ` Pavel Machek
2001-03-02 12:01 ` Oystein Viggen
2001-03-02 12:26 ` Tobias Ringstrom
2001-03-02 12:58 ` David Weinehall
2001-03-02 19:33 ` Tim Wright
2001-03-12 10:05 ` Herbert Xu
2001-03-12 10:43 ` Xavier Bestel
2001-03-01 21:23 ` Andreas Dilger
2001-03-01 21:26 ` Bill Crawford
2001-03-01 21:05 ` Tigran Aivazian
2001-03-02 8:56 ` Pavel Machek
2001-03-07 0:37 ` Jamie Lokier
2001-03-07 4:03 ` Linus Torvalds
2001-03-07 13:41 ` Jamie Lokier
2001-03-02 9:00 ` Pavel Machek
2001-03-03 0:03 ` Bill Crawford
2001-03-08 12:42 ` Goswin Brederlow
2001-04-27 16:20 ` Daniel Phillips
2001-02-22 23:22 ` H. Peter Anvin
2001-02-22 23:54 ` Bill Crawford
2001-03-10 11:22 ` Kai Henningsen
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