Date: Thu, 1 Mar 2012 15:27:27 +0100 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Attilio Rao <attilio@FreeBSD.org>, arch@FreeBSD.org, Gleb Kurtsou <gleb.kurtsou@gmail.com> Subject: Re: Prefaulting for i/o buffers Message-ID: <20120301142726.GF1336@garage.freebsd.pl> In-Reply-To: <20120301141553.GT55074@deviant.kiev.zoral.com.ua> References: <20120203193719.GB3283@deviant.kiev.zoral.com.ua> <CAJ-FndABi21GfcCRTZizCPc_Mnxm1EY271BiXcYt9SD_zXFpXw@mail.gmail.com> <20120225151334.GH1344@garage.freebsd.pl> <CAJ-FndBBKHrpB1MNJTXx8gkFXR2d-O6k5-HJeOAyv2DznpN-QQ@mail.gmail.com> <20120225194630.GI1344@garage.freebsd.pl> <20120301111624.GB30991@reks> <20120301141247.GE1336@garage.freebsd.pl> <20120301141553.GT55074@deviant.kiev.zoral.com.ua>
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--KR/qxknboQ7+Tpez Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Mar 01, 2012 at 04:15:53PM +0200, Konstantin Belousov wrote: > On Thu, Mar 01, 2012 at 03:12:47PM +0100, Pawel Jakub Dawidek wrote: > > Yes, namecache is already library-like, but I was talking about the > > buffer cache. I managed to bypass it eventually with suggestions from > > ups@, but for a long time I was sure it isn't at all possible. >=20 > I am quite curious, in which way buffer layer is mandatory ? As I said, it is not, but it took me a while to figure it out. I remember having massive problems when I was working on getting mmaped reads/writes right and bypassing the buffer cache and talking to the page cache directly. I don't think there was single example in the tree that was showing it can be done at that time. Currently tmpfs is using the same approach as ZFS, AFAIK. --=20 Pawel Jakub Dawidek http://www.wheelsystems.com FreeBSD committer http://www.FreeBSD.org Am I Evil? Yes, I Am! http://tupytaj.pl --KR/qxknboQ7+Tpez Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iEYEARECAAYFAk9Ph04ACgkQForvXbEpPzS4gwCgiqSLlzrJ2LRC4FHPSOVsjCQd ZbwAn1yCaWUq3kik4zzQ+ClcPCQsUpbk =LM1U -----END PGP SIGNATURE----- --KR/qxknboQ7+Tpez--
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