From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>,
Linus Torvalds <torvalds@linux-foundation.org>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Anton Arapov <anton@redhat.com>
Subject: Re: [PATCH 1/3] uprobes/core: Remove redundant lock_page/unlock_page
Date: Thu, 31 May 2012 20:37:56 +0530 [thread overview]
Message-ID: <20120531150756.GC24279@linux.vnet.ibm.com> (raw)
In-Reply-To: <1338465518.28384.55.camel@twins>
* Peter Zijlstra <peterz@infradead.org> [2012-05-31 13:58:38]:
> On Thu, 2012-05-31 at 17:16 +0530, Srikar Dronamraju wrote:
> > From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> >
> > No need to lock the page when copying the opcode in read_opcode().
>
> It would be good if the changelog said _why_ this is so :-)
In read_opcode(), we have the reference for the page and we only are reading
from the the page. i.e we are neither modifying the page contents, not
the page attributes.
Existing kernel code has enough examples where we read the contents
of the page without taking the page lock.
Further this was discussed here too https://lkml.org/lkml/2012/4/17/361.
--
Thanks and Regards
Srikar
next prev parent reply other threads:[~2012-05-31 15:12 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-31 11:46 [PATCH 1/3] uprobes/core: Remove redundant lock_page/unlock_page Srikar Dronamraju
2012-05-31 11:46 ` [PATCH 2/3] perf/uprobes: Remove unnecessary check before strlist__delete Srikar Dronamraju
2012-06-06 7:08 ` [tip:perf/urgent] perf uprobes: " tip-bot for Srikar Dronamraju
2012-05-31 11:46 ` [PATCH 3/3] perf: Check for valid dso before creating map Srikar Dronamraju
2012-06-06 7:07 ` [tip:perf/urgent] perf symbols: " tip-bot for Srikar Dronamraju
2012-05-31 11:58 ` [PATCH 1/3] uprobes/core: Remove redundant lock_page/unlock_page Peter Zijlstra
2012-05-31 14:22 ` Steven Rostedt
2012-05-31 15:07 ` Srikar Dronamraju [this message]
2012-05-31 16:56 ` Peter Zijlstra
2012-05-31 16:58 ` Srikar Dronamraju
2012-06-01 9:19 ` [RESEND PATCH 1/3] uprobes: " Srikar Dronamraju
2012-06-01 18:52 ` Oleg Nesterov
2012-06-06 9:18 ` Ingo Molnar
2012-06-06 9:19 ` Peter Zijlstra
2012-08-06 11:57 ` Anton Arapov
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