From: Matthew Wilcox <willy@debian.org>
To: Andrew Morton <akpm@zip.com.au>
Cc: Dave Hansen <haveblue@us.ibm.com>,
matthew@wil.cx, linux-kernel@vger.kernel.org
Subject: Re: fs/locks.c BKL removal
Date: Sat, 11 May 2002 20:48:20 +0100 [thread overview]
Message-ID: <20020511204820.N32414@parcelfarce.linux.theplanet.co.uk> (raw)
In-Reply-To: <3CDC4037.8040104@us.ibm.com> <3CDC45EF.9000506@us.ibm.com> <3CDC5509.DCAF336A@zip.com.au>
On Fri, May 10, 2002 at 04:17:29PM -0700, Andrew Morton wrote:
> It was I who put the BKL back into locks.c, much to
> Matthew's disgust...
The disgust was targetted more at removing the abstraction of
locking scheme which I'd put in and having explicit lock_kernel() /
unlock_kernel() calls. I'd used (iirc) acquire_lock() / release_lock()
macros which could have just been redefined.
> The problem was that replacing the BKL with a semaphore
> seriously damaged Apache thoughput on 8-way. Apache
> was using flock()-based synchronisation and replacing
> a spin with a schedule just killed it.
Which says that our semaphores suck, because they don't try to spin for a
bit before scheduling. Of course, your change back was the right thing
to do in the 2.3.late timeframe.
--
Revolutions do not require corporate support.
next prev parent reply other threads:[~2002-05-11 19:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-05-10 21:48 Dave Hansen
2002-05-10 22:13 ` Dave Hansen
2002-05-10 23:17 ` Andrew Morton
2002-05-11 19:48 ` Matthew Wilcox [this message]
2002-05-11 19:45 ` Matthew Wilcox
2002-05-12 1:40 ` Dave Hansen
2002-05-12 2:07 ` Matthew Wilcox
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