From: Christoph Lameter <clameter@sgi.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC 4/9] Atomic reclaim: Save irq flags in vmscan.c
Date: Tue, 14 Aug 2007 15:41:53 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0708141540140.364@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <20070814222150.GI23308@one.firstfloor.org>
On Wed, 15 Aug 2007, Andi Kleen wrote:
> > Ok I have a vague idea on how this could but its likely that the
> > changes make things worse rather than better. Additional reference to a
> > new cacheline (per cpu but still), preempt disable. Lots of code at all
> > call sites. Interrupt enable/disable is quite efficient in recent
> > processors.
>
> The goal of this was not to be faster than interrupt disable,
> but to avoid the interrupt latency impact. This might be a problem
> when spending a lot of time inside the locks.
Both. They need to be fast too and not complicate the kernel too much. I
have not seen a serious holdoff case. The biggest issue is still the
zone->lru lock but interrupts are always disabled for that one already.
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next prev parent reply other threads:[~2007-08-14 22:41 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-14 15:30 [RFC 0/9] Reclaim during GFP_ATOMIC allocs Christoph Lameter
2007-08-14 15:30 ` [RFC 1/9] Allow reclaim via __GFP_NOMEMALLOC reclaim Christoph Lameter
2007-08-14 15:30 ` [RFC 2/9] Use NOMEMALLOC reclaim to allow reclaim if PF_MEMALLOC is set Christoph Lameter
2007-08-18 7:10 ` Pavel Machek
2007-08-20 19:00 ` Christoph Lameter
2007-08-20 20:17 ` Peter Zijlstra
2007-08-20 20:27 ` Christoph Lameter
2007-08-20 21:14 ` Peter Zijlstra
2007-08-20 21:17 ` Christoph Lameter
2007-08-21 14:07 ` Peter Zijlstra
2007-08-21 0:39 ` Nick Piggin
2007-08-21 14:07 ` Peter Zijlstra
2007-08-23 3:38 ` Nick Piggin
2007-08-23 9:26 ` Peter Zijlstra
2007-08-23 10:11 ` Nikita Danilov
2007-08-23 13:58 ` Peter Zijlstra
2007-08-24 4:00 ` Nick Piggin
2007-08-14 15:30 ` [RFC 3/9] Make cond_rescheds conditional on __GFP_WAIT Christoph Lameter
2007-08-14 15:30 ` [RFC 4/9] Atomic reclaim: Save irq flags in vmscan.c Christoph Lameter
2007-08-14 20:02 ` Andi Kleen
2007-08-14 19:12 ` Christoph Lameter
2007-08-14 20:05 ` Peter Zijlstra
2007-08-14 20:34 ` Andi Kleen
2007-08-14 20:33 ` Andi Kleen
2007-08-14 20:42 ` Christoph Lameter
2007-08-14 20:44 ` Andi Kleen
2007-08-14 21:15 ` Christoph Lameter
2007-08-14 21:23 ` Andi Kleen
2007-08-14 21:26 ` Christoph Lameter
2007-08-14 21:29 ` Andi Kleen
2007-08-14 21:37 ` Christoph Lameter
2007-08-14 21:44 ` Andi Kleen
2007-08-14 21:48 ` Christoph Lameter
2007-08-14 21:56 ` Andi Kleen
2007-08-14 22:07 ` Christoph Lameter
2007-08-14 22:16 ` Andi Kleen
2007-08-14 22:20 ` Christoph Lameter
2007-08-14 22:21 ` Andi Kleen
2007-08-14 22:41 ` Christoph Lameter [this message]
2007-08-14 15:30 ` [RFC 5/9] Save irqflags on taking the mapping lock Christoph Lameter
2007-08-14 15:30 ` [RFC 6/9] Disable irqs on taking the private_lock Christoph Lameter
2007-08-14 15:30 ` [RFC 7/9] Save flags in swap.c Christoph Lameter
2007-08-14 15:30 ` [RFC 8/9] Reclaim on an atomic allocation if necessary Christoph Lameter
2007-08-14 15:30 ` [RFC 9/9] Testing: Perform GFP_ATOMIC overallocation Christoph Lameter
2007-08-16 2:49 ` [RFC 0/9] Reclaim during GFP_ATOMIC allocs Nick Piggin
2007-08-16 20:24 ` Christoph Lameter
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