Date: Thu, 3 Apr 2014 23:10:49 +0400 From: Dmitry Sivachenko <trtrmitya@gmail.com> To: John Baldwin <jhb@FreeBSD.org> Cc: freebsd-hackers@freebsd.org, Ian Lepore <ian@freebsd.org>, =?iso-8859-1?Q?Trond_Endrest=F8l?= <Trond.Endrestol@fagskolen.gjovik.no> Subject: Re: madvise() vs posix_fadvise() Message-ID: <2CB392D0-5198-41EB-8191-8B02FE432334@gmail.com> In-Reply-To: <201404031230.40380.jhb@freebsd.org> References: <D6BD48AF-9522-495D-8D54-37854E53C272@gmail.com> <201404031102.38598.jhb@freebsd.org> <1396539837.81853.278.camel@revolution.hippie.lan> <201404031230.40380.jhb@freebsd.org>
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On 03 =C1=D0=D2. 2014 =C7., at 20:30, John Baldwin <jhb@FreeBSD.org> = wrote: >=20 > The latter. It's sort of like a lazy O_DIRECT. Each time you call = write(2), > it tries to move any clean pages from your current sequentially = written > stream from inactive to cache, so the pages won't move until a = subsequent > write(2) after bufdaemon or the syncer actually forces them to be = written. > Unfortunately, it is currently implemented by doing an internal > FADV_DONTNEED after each read() or write(). It would be better if it = was > implemented as a callback when buffers are completed. Sounds like FADV_NOREUSE should be befeficial for any log-writing = program? (syslogd, apache, nginx, .....)=
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