From: mingming cao <cmm@us.ibm.com>
To: dipankar@in.ibm.com
Cc: Hugh Dickins <hugh@veritas.com>, Andrew Morton <akpm@digeo.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH]IPC locks breaking down with RCU
Date: Mon, 21 Oct 2002 12:41:58 -0700 [thread overview]
Message-ID: <3DB45886.3DDE1CC8@us.ibm.com> (raw)
In-Reply-To: 20021022004806.A10573@in.ibm.com
Dipankar Sarma wrote:
>
> I took a quick look at the original ipc code and I don't understand
> something - it seems to me the ipc_ids structs are protected by the semaphore
> inside for all operations, so why do we need the spinlock in the
> first place ? Am I missing something here ?
The semaphore is used to protect the fields in ipc_ids structure, while
the spinlock is used to protect IPC ids. For the current implementation,
there is one spinlock for all IPC ids of the same type(i.e. for all
messages queues). The patch is intend to breaks down the global
spinlock and have a lock per IPC id.
next prev parent reply other threads:[~2002-10-21 19:38 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-18 0:14 [PATCH]IPC locks breaking down with RCU mingming cao
2002-10-20 13:14 ` Hugh Dickins
2002-10-20 17:27 ` Hugh Dickins
2002-10-21 18:11 ` mingming cao
2002-10-21 19:00 ` Hugh Dickins
2002-10-24 21:49 ` [PATCH]updated ipc lock patch mingming cao
2002-10-24 22:29 ` Andrew Morton
2002-10-24 22:56 ` Hugh Dickins
2002-10-24 23:30 ` Andrew Morton
2002-10-24 23:59 ` Hugh Dickins
2002-10-25 0:35 ` [Lse-tech] " Rick Lindsley
2002-10-25 1:07 ` Robert Love
2002-10-25 0:07 ` mingming cao
2002-10-25 0:24 ` Andrew Morton
2002-10-25 4:18 ` Rusty Russell
2002-10-25 5:53 ` mingming cao
2002-10-25 7:27 ` Rusty Russell
2002-10-25 5:36 ` Manfred Spraul
2002-10-25 16:53 ` Rik van Riel
2002-10-24 23:23 ` mingming cao
2002-10-25 14:21 ` [Lse-tech] " Paul Larson
2002-10-25 17:17 ` mingming cao
2002-10-25 18:20 ` Paul Larson
2002-10-25 18:51 ` mingming cao
2002-10-25 19:06 ` Paul Larson
2002-10-25 20:14 ` mingming cao
2002-10-25 20:23 ` Manfred Spraul
2002-10-25 0:38 ` Cliff White
2002-10-31 17:52 ` [Lse-tech] Re: [PATCH]updated ipc lock patch [PERFORMANCE RESULTS] Bill Hartner
2002-10-21 19:18 ` [PATCH]IPC locks breaking down with RCU Dipankar Sarma
2002-10-21 19:36 ` Hugh Dickins
2002-10-21 19:41 ` mingming cao [this message]
2002-10-21 20:14 ` Dipankar Sarma
2002-10-21 18:07 ` mingming cao
-- strict thread matches above, loose matches on Subject: below --
2002-10-21 19:23 Manfred Spraul
2002-10-21 20:10 ` Hugh Dickins
2002-10-21 20:34 ` mingming cao
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