Date: Wed, 25 Jan 2012 14:56:55 -0800 From: Julian Elischer <julian@freebsd.org> To: John Baldwin <jhb@freebsd.org> Cc: freebsd-current@freebsd.org, Tijl Coosemans <tijl@coosemans.org> Subject: Re: posix_fadvise noreuse disables file caching Message-ID: <4F2088B7.7030308@freebsd.org> In-Reply-To: <201201251129.22368.jhb@freebsd.org> References: <201201191739.48327.tijl@coosemans.org> <201201201412.13269.jhb@freebsd.org> <201201251129.22368.jhb@freebsd.org>
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On 1/25/12 8:29 AM, John Baldwin wrote: > > So I've came up with this untested patch. It uses > VOP_ADVISE(FADV_DONTNEED) after read(2) calls to a NOREUSE region, and > leaves read-ahead caching enabled for NOREUSE. FADV_DONTNEED doesn't > do any good really for writes (it only flushes clean buffers), so I've > left write(2) operations as using IO_DIRECT still. Does this sound > reasonable? That sounds like a good solution. If people want something from write they can do it separately. For what it's worth, I would expect NOREUSE on write to still do write clustering but to free the buffer once it is written.
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