Date: Sat, 25 Jul 1998 20:41:41 -0500 From: Karl Denninger <karl@mcs.net> To: Brian Feldman <green@zone.baldcom.net> Cc: IBS / Andre Oppermann <andre@pipeline.ch>, current@FreeBSD.ORG Subject: Re: MMAP problems Message-ID: <19980725204141.39635@mcs.net> In-Reply-To: <Pine.BSF.4.00.9807251817390.6651-100000@zone.baldcom.net>; from Brian Feldman on Sat, Jul 25, 1998 at 06:20:19PM -0400 References: <35BA4F9A.3E28B29E@pipeline.ch> <Pine.BSF.4.00.9807251817390.6651-100000@zone.baldcom.net>
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On Sat, Jul 25, 1998 at 06:20:19PM -0400, Brian Feldman wrote: > Hmm, what is the default behavior of msync()? Is it handled automatically, > say, in-kernel? If so, maybe it needs to be explicitly called; also is > this daemon using a drive with async/softupdates by any chance? > > Cheers, > Brian Feldman > green@unixhelp.org Its not using a drive which is mounted async or with softupdates. Msync is *NOT* called anywhere in the code that I can find. However, this code is reported to work on a lot of other platforms/systems, and on *SOME* versions of FreeBSD without trouble. It is definitely broken on -current, although not "badly"; the problem happens infrequently, but often enough to piss me off. The real problem is that I don't know what the bad sequence of calls is, and therefore, I have to consider mmap() and friends (including the SYSVSHM implementation, which uses it) unusable. This is a *bad* thing over all, and something that the FreeBSD folks really need to consider doing something about - not having usable and reliable mmap/SHM capability basically destroys FreeBSD as a DBMS or news server if you care about minor things like data integrity. -- -- Karl Denninger (karl@MCS.Net)| MCSNet - Serving Chicagoland and Wisconsin http://www.mcs.net/ | T1's from $600 monthly / All Lines K56Flex/DOV | NEW! Corporate ISDN Prices dropped by up to 50%! Voice: [+1 312 803-MCS1 x219]| EXCLUSIVE NEW FEATURE ON ALL PERSONAL ACCOUNTS Fax: [+1 312 803-4929] | *SPAMBLOCK* Technology now included at no cost To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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