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Date: Sat, 20 Jul 2002 22:47:33 -0400
From: Pete Zaitcev <zaitcev@redhat.com>
Message-Id: <200207210247.g6L2lXE13782@devserv.devel.redhat.com>
To: Robert Love <rml@tech9.net>, akpm@zip.com.au
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] low-latency zap_page_range
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> The lock hold time in zap_page_range is horrid.  This patch breaks the
> work up into chunks and relinquishes the lock after each iteration. 
> This drastically lowers latency by creating a preemption point, as well
> as lowering lock contention. 

>  void zap_page_range(struct vm_area_struct *vma, unsigned long address, unsigned long size)

Arjan sent me something similar, done by AKPM, only he did this a
little differently. He added an argument to zap_page_range
which allowed to work it in the old way, if set. Then, he set it so
all places would use low latency EXCEPT a reading from /dev/zero.
I assume it was some locking somewhere in devices/char/mem.c,
though I was unable to figure which in particular.

Andrew, care to unconfuse me?

-- Pete
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