LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Mathieu Desnoyers <compudj@krystal.dyndns.org>
To: Andrew Morton <akpm@osdl.org>
Cc: Greg Kroah-Hartman <gregkh@suse.de>,
	Richard J Moore <richardj_moore@uk.ibm.com>,
	linux-kernel@vger.kernel.org,
	"Martin J. Bligh" <mbligh@mbligh.org>,
	Christoph Hellwig <hch@infradead.org>,
	Douglas Niehaus <niehaus@eecs.ku.edu>,
	Ingo Molnar <mingo@redhat.com>,
	ltt-dev@shafik.org, systemtap@sources.redhat.com,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] minimize lockdep_on/off side-effect
Date: Wed, 24 Jan 2007 12:55:57 -0500	[thread overview]
Message-ID: <20070124175557.GA160@Krystal> (raw)
In-Reply-To: <20070124172445.GA1145@Krystal>

Minimize lockdep_on/off side-effect on irq tracing in vprintk by using
raw_local_irq_save/restore _around_ lockdep_off/on().

It applies on the previous patch. It has the advantage of not losing the IRQ
events coming between the lockdep disabling and the irq disabling.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>

 
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -530,8 +530,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 		zap_locks();
 
 	/* This stops the holder of console_sem just where we want him */
+	raw_local_irq_save(flags);
 	lockdep_off();
-	local_irq_save(flags);
 	spin_lock(&logbuf_lock);
 	printk_cpu = smp_processor_id();
 
@@ -640,8 +640,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 			console_locked = 0;
 			up(&console_sem);
 		}
-		local_irq_restore(flags);
 		lockdep_on();
+		raw_local_irq_restore(flags);
 	} else {
 		/*
 		 * Someone else owns the drivers.  We drop the spinlock, which
@@ -650,8 +650,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 		 */
 		printk_cpu = UINT_MAX;
 		spin_unlock(&logbuf_lock);
-		local_irq_restore(flags);
 		lockdep_on();
+		raw_local_irq_restore(flags);
 	}
 
 	preempt_enable();
-- 
OpenPGP public key:              http://krystal.dyndns.org:8080/key/compudj.gpg
Key fingerprint:     8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68 

  reply	other threads:[~2007-01-24 17:56 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-12-20 23:52 [PATCH 0/4] Linux Kernel Markers Mathieu Desnoyers
2006-12-20 23:57 ` [PATCH 1/4] Linux Kernel Markers : Architecture agnostic code Mathieu Desnoyers
2006-12-20 23:59 ` [PATCH 2/4] Linux Kernel Markers : kconfig menus Mathieu Desnoyers
2006-12-21  0:00 ` [PATCH 3/4] Linux Kernel Markers : i386 optimisation Mathieu Desnoyers
2006-12-21  0:01 ` [PATCH 4/4] Linux Kernel Markers : powerpc optimisation Mathieu Desnoyers
2007-01-13  1:33 ` [PATCH 0/4] Linux Kernel Markers Richard J Moore
2007-01-13  5:45   ` Mathieu Desnoyers
2007-01-16 17:41     ` [PATCH 0/4 update] Linux Kernel Markers - i386 : pIII erratum 49 : XMC Mathieu Desnoyers
2007-01-16 18:35       ` Frank Ch. Eigler
2007-01-16 21:27       ` [PATCH 0/4 update] kprobes and traps Mathieu Desnoyers
2007-01-17 12:25         ` S. P. Prasanna
2007-01-16 17:56   ` [PATCH 1/2] lockdep missing barrier() Mathieu Desnoyers
2007-01-24  4:26     ` Andrew Morton
2007-01-24 16:51       ` Mathieu Desnoyers
2007-01-24 17:24         ` [PATCH] order of lockdep off/on in vprintk() should be changed Mathieu Desnoyers
2007-01-24 17:55           ` Mathieu Desnoyers [this message]
2007-01-16 17:56   ` [PATCH 2/2] lockdep reentrancy Mathieu Desnoyers
2007-01-24  4:29     ` Andrew Morton
2007-01-24 16:55       ` Mathieu Desnoyers

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20070124175557.GA160@Krystal \
    --to=compudj@krystal.dyndns.org \
    --cc=akpm@osdl.org \
    --cc=gregkh@suse.de \
    --cc=hch@infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=ltt-dev@shafik.org \
    --cc=mbligh@mbligh.org \
    --cc=mingo@redhat.com \
    --cc=niehaus@eecs.ku.edu \
    --cc=richardj_moore@uk.ibm.com \
    --cc=systemtap@sources.redhat.com \
    --cc=tglx@linutronix.de \
    --subject='Re: [PATCH] minimize lockdep_on/off side-effect' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).