From: Jamie Lokier <jamie@shareable.org>
To: Andi Kleen <ak@muc.de>
Cc: Linus Torvalds <torvalds@transmeta.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Runtime memory barrier patching
Date: Tue, 22 Apr 2003 00:57:32 +0100 [thread overview]
Message-ID: <20030421235732.GA17793@mail.jlokier.co.uk> (raw)
In-Reply-To: <20030421234611.GA15191@averell>
Andi Kleen wrote:
> > Such as removing the lock prefix when running non-SMP?
...
> .altinstructions section after load to avoid too much kernel bloat (it
> currently costs 7 byte + the length of the replacement. And lock
> is quite common in the kernel these days.
1. It should cost at most 4 bytes, in a table of "remove me" address,
with topmost bits of each word used to give the length of the
instruction to remove - i.e. to replace with an optimal nop sequence.
2. Not just locks - a lot of spinlock code could be removed completely.
I don't have an opinion on whether this is worth doing - one can
simply run a UP kernel after all.
-- Jamie
next prev parent reply other threads:[~2003-04-21 23:45 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-21 19:27 Andi Kleen
2003-04-21 19:59 ` Linus Torvalds
2003-04-21 20:53 ` Andi Kleen
2003-04-21 21:04 ` Linus Torvalds
2003-04-21 21:43 ` Ulrich Drepper
2003-04-21 22:05 ` Linus Torvalds
2003-04-21 22:45 ` Andi Kleen
2003-04-21 22:11 ` Andi Kleen
2003-04-21 22:23 ` Linus Torvalds
2003-04-21 22:59 ` Andi Kleen
2003-04-21 23:35 ` Jamie Lokier
2003-04-21 23:46 ` Andi Kleen
2003-04-21 23:56 ` [PATCH] Runtime memory barrier patching II Andi Kleen
2003-04-21 23:57 ` Jamie Lokier [this message]
2003-04-22 0:06 ` [PATCH] Runtime memory barrier patching Linus Torvalds
2003-04-22 0:13 ` Jamie Lokier
2003-04-21 23:41 Chuck Ebbert
2003-04-22 0:04 ` Jamie Lokier
[not found] <200304220111.h3M1BEp5004047@hera.kernel.org>
2003-04-22 8:43 ` Arjan van de Ven
2003-04-22 11:18 ` Andi Kleen
2003-04-22 16:11 ` Dave Jones
2003-04-22 10:12 Chuck Ebbert
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