From: Andi Kleen <ak@muc.de>
To: Matthew Wilcox <willy@debian.org>
Cc: Andi Kleen <ak@muc.de>, "David S. Miller" <davem@redhat.com>,
akpm@digeo.com, linux-kernel@vger.kernel.org, anton@samba.org,
schwidefsky@de.ibm.com, davidm@hpl.hp.com, matthew@wil.cx,
ralf@linux-mips.org, rth@redhat.com
Subject: Re: Reduce struct page by 8 bytes on 64bit
Date: Wed, 16 Apr 2003 17:04:27 +0200 [thread overview]
Message-ID: <20030416150427.GA2496@averell> (raw)
In-Reply-To: <20030416145532.GA1505@parcelfarce.linux.theplanet.co.uk>
On Wed, Apr 16, 2003 at 04:55:32PM +0200, Matthew Wilcox wrote:
> On Wed, Apr 16, 2003 at 04:43:12PM +0200, Andi Kleen wrote:
> > On sparc64. But is that true too for all other 64bit architectures supported?
> >
> > e.g. How about PA-RISC? (always seems to do things differently)
>
> As you know our only two atomic ops are load-and-clear 32-bit quantity and
> load-and-clear 64-bit quantity. so we take one of the hashed spinlocks ..
Sure, but you use a 64bit read/store in set_bit/clear_bit etc., right?
If yes then you can't use this unless you rewrite them to use 32bit store
- otherwise it will conflict with the atomic_t counter in the 64bit slot
which is not protected.
I think my current patch is fine for you - you can still optimize it
this way, but it should already work. Jakub's version would break though.
-Andi
next prev parent reply other threads:[~2003-04-16 14:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-04-15 11:24 Reduce struct page by 8 bytes on 64bit Andi Kleen
2003-04-16 12:45 ` David S. Miller
2003-04-16 13:22 ` Jakub Jelinek
2003-04-16 14:07 ` Andi Kleen
2003-04-16 14:26 ` David S. Miller
2003-04-16 14:43 ` Andi Kleen
2003-04-16 14:38 ` David S. Miller
2003-04-16 14:58 ` Andi Kleen
2003-04-16 14:58 ` David S. Miller
2003-04-16 14:55 ` Matthew Wilcox
2003-04-16 15:04 ` Andi Kleen [this message]
2003-04-16 15:00 ` David S. Miller
2003-04-16 15:11 ` Matthew Wilcox
2003-04-16 20:35 ` Andrew Morton
2003-04-16 21:26 ` Matthew Wilcox
2003-04-16 21:43 ` Andrew Morton
2003-04-16 21:40 ` David S. Miller
2003-04-17 15:20 ` Andi Kleen
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