Date: Thu, 26 Feb 2004 14:10:33 +0100 (CET) From: Phil Regnauld <regnauld+freebsd@catpipe.net> To: FreeBSD-gnats-submit@FreeBSD.org Subject: bin/63388: Patch to make syslogd optionally not fsync kernel messages Message-ID: <20040226131033.990E276317@chef.catpipe.net> Resent-Message-ID: <200402261320.i1QDKD0w027193@freefall.freebsd.org>
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>Number: 63388
>Category: bin
>Synopsis: Patch to make syslogd optionally not fsync kernel messages
>Confidential: no
>Severity: non-critical
>Priority: medium
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: change-request
>Submitter-Id: current-users
>Arrival-Date: Thu Feb 26 05:20:13 PST 2004
>Closed-Date:
>Last-Modified:
>Originator: Phil Regnauld
>Release: FreeBSD 4.9-RELEASE i386
>Organization:
catpipe Systems ApS
>Environment:
System: gw.catpipe.net 4.9-RELEASE FreeBSD 4.9-RELEASE #0: Sat Jan 17 15:37:54 CET 2004 regnauld@gw.catpipe.net:/data/src/sys/compile/GW i386
>Description:
By default, the syslogd will call fsync after every write when logging
message coming from the kernel. This can be problematic in the event
that many kernel messages are being logged to disk in a rapid
succession (i.e.: firewall logging). This patch implements a new
option for syslogd, -K, which disables fsyncing upon reception
kernel messages.
>How-To-Repeat:
n/a
>Fix:
--- syslogd.c.orig Tue Jan 20 16:12:43 2004
+++ syslogd.c Tue Jan 20 16:16:53 2004
@@ -286,6 +286,7 @@
static int LogFacPri; /* Put facility and priority in log message: */
/* 0=no, 1=numeric, 2=names */
static int KeepKernFac; /* Keep remotely logged kernel facility */
+static int NoSyncKern; /* Don't fsync on /dev/klog messages */
volatile sig_atomic_t MarkSet, WantDie;
@@ -367,6 +368,9 @@
case 'k': /* keep remote kern fac */
KeepKernFac = 1;
break;
+ case 'K': /* no sync on /dev/klog */
+ NoSyncKern = 1;
+ break;
case 'l':
if (nfunix < MAXFUNIX)
funixn[nfunix++] = optarg;
@@ -732,7 +736,7 @@
{
int pri, flags;
- flags = ISKERNEL | SYNC_FILE | ADDDATE; /* fsync after write */
+ flags = ISKERNEL | ( NoSyncKern ? 0x000 : SYNC_FILE) | ADDDATE; /* fsync after write */
pri = DEFSPRI;
if (*p == '<') {
pri = 0;
--- syslogd.8.orig Tue Jan 20 16:19:33 2004
+++ syslogd.8 Tue Jan 20 16:21:17 2004
@@ -181,6 +181,9 @@
.Dq kern
facility is reserved for messages read directly from
.Pa /dev/klog .
+.It Fl K
+Disable fsync after write (the default) on messages read from
+.Pa /dev/klog .
.It Fl m
Select the number of minutes between
.Dq mark
>Release-Note:
>Audit-Trail:
>Unformatted:
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