Date: Fri, 15 Dec 2000 23:01:30 +0100 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: David Malone <dwmalone@maths.tcd.ie> Cc: John Baldwin <jhb@FreeBSD.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern subr_log.c Message-ID: <1593.976917690@critter> In-Reply-To: Your message of "Fri, 15 Dec 2000 21:59:01 GMT." <20001215215901.B35080@gosset.maths.tcd.ie>
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In message <20001215215901.B35080@gosset.maths.tcd.ie>, David Malone writes: >On Fri, Dec 15, 2000 at 01:23:34PM -0800, John Baldwin wrote: > >> Delay waking up processes select'ing on the log device directly from >> the kernel console. Instead, change logwakeup() to set a flag in the >> softc. A callout then wakes up every so often and wakes up any processes >> selecting on /dev/log (such as syslogd) if the flag is set. By default >> this callout fires 5 times a second, but that can be adjusted by the >> sysctl kern.log_wakeups_per_second. > >Can you explain the idea of this patch? Is it just to reduce the >number of wakeups that syslogd gets? Can the kernel log buffer >wrap and messages get lost? No, the point is that doing a selwakeup() from a printf(9) is not always a good idea since you have to lock down processes and stuff like that. This patch isolates syslogd() with a simple flag, allowing printf(9) to be used in circumstances where the system would just go south if it tried to do a selwakeup() on the syslogd. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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