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From: Dipankar Sarma <dipankar@in.ibm.com>
To: "David S. Miller" <davem@redhat.com>
Cc: William Lee Irwin III <wli@holomorphy.com>,
	Andrew Morton <akpm@digeo.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: 2.5.69-mm1
Date: Tue, 6 May 2003 20:55:55 +0530	[thread overview]
Message-ID: <20030506152555.GC9875@in.ibm.com> (raw)
In-Reply-To: <1052222542.983.27.camel@rth.ninka.net>

On Tue, May 06, 2003 at 05:02:22AM -0700, David S. Miller wrote:
> On Tue, 2003-05-06 at 04:09, Dipankar Sarma wrote:
> > That brings me to the point - with the fget-speedup patch, we should
> > probably change ->file_lock back to an rwlock again. We now take this
> > lock only when fd table is shared and under such situation the rwlock
> > should help. Andrew, it that ok ?
> 
> rwlocks believe it or not tend not to be superior over spinlocks,
> they actually promote cache line thrashing in the case they
> are actually being effective (>1 parallel reader)

Provided there isn't a very heavy contention among readers for the spin_lock.
There is no evidence that this happens with ->file_lock as
spin_lock, so I guess we are ok for now. We should probably watch out
for some multi-threaded programs (Java->posix-threads ?) on
large smp boxes though.

Thanks
Dipankar

  reply	other threads:[~2003-05-06 15:11 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-05-05  6:16 2.5.69-mm1 Andrew Morton
2003-05-05 15:32 ` 2.5.69-mm1 Andrei Ivanov
2003-05-05 16:45   ` 2.5.69-mm1 Greg KH
2003-05-06  9:49     ` 2.5.69-mm1 Andrei Ivanov
2003-05-05 18:44   ` 2.5.69-mm1 Andrew Morton
2003-05-05 21:01 ` 2.5.69-mm1 William Lee Irwin III
2003-05-06 11:09   ` 2.5.69-mm1 Dipankar Sarma
2003-05-06 12:02     ` 2.5.69-mm1 David S. Miller
2003-05-06 15:25       ` Dipankar Sarma [this message]
2003-05-06 14:20         ` 2.5.69-mm1 David S. Miller
2003-05-06 15:47           ` 2.5.69-mm1 Dipankar Sarma
2003-05-05 21:02 ` 2.5.69-mm1 William Lee Irwin III
2003-05-06 14:33 ` 2.5.69-mm1 Steven Cole
2003-05-06 15:33   ` 2.5.69-mm1 Andrew Morton
2003-05-06 15:36     ` 2.5.69-mm1 Eric W. Biederman
2003-05-06 16:35       ` 2.5.69-mm1 Steven Cole

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