Date: Mon, 11 Mar 2013 23:11:58 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Lev Serebryakov <lev@serebryakov.spb.ru> Cc: Dag-Erling Sm??rgrav <des@des.no>, arch@freebsd.org Subject: Re: Unmapped buffers: to be merged in several days Message-ID: <20130311211158.GE3794@kib.kiev.ua> In-Reply-To: <329178079.20130312010425@serebryakov.spb.ru> References: <20130311091852.GR3794@kib.kiev.ua> <86k3pe1cl3.fsf@ds4.des.no> <20130311182454.GX3794@kib.kiev.ua> <329178079.20130312010425@serebryakov.spb.ru>
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--JU1P3uBe1BU9Y2xT Content-Type: text/plain; charset=koi8-r Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 12, 2013 at 01:04:25AM +0400, Lev Serebryakov wrote: > Hello, Konstantin. > You wrote 11 =CD=C1=D2=D4=C1 2013 =C7., 22:24:54: >=20 > KB> If the class does need to access the bio data, to be marked > KB> unmapped-processing, the class should be rewritten. Now, the class > KB> should verify is the bio passed is mapped or not, and process the pag= es > KB> passed in the bio_ma array instead of bio_data. The involved example = is > KB> sys/dev/md/md.c. > Will GEOM class, which needs to touch data (like raid3 or my off-tree > raid5), benefit from conversion, compare to generic mechanism, > provided for not-converted by your patch? First, what do you mean by 'benefit'. Answer would obviously depend on the criteria. Second, I do not think that any wizard can usefully answer this question, for usual criteria like speed or code maintanability. FWIW, I tried to get an Intel documentation for IOAT engine which should allow to perform the XOR checksumming of the unmapped buffers, suitable for e.g. hardware-assisted software raid5, but did not succeeded. --JU1P3uBe1BU9Y2xT Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iQIcBAEBAgAGBQJRPkieAAoJEJDCuSvBvK1BU58P/R1NuIJ5JnEjBO5jQ6dOrDV0 RiyFHXaHZeHIEQsPe5mtgCjOLcRD2OBicTgnjJK/el8UBsuF9LrUpkX76ATfoj10 ibMi8oB61ZR1ub9llmXlEA1vykZxV1CbODPhokAQLvf3bEJLxOLLIEajtNsmlbkE sBB9fP5KcrHIfv57Ya/mnVEeQo9tC3NPsmXdq/fJZu7wj7zwU+nSMX8jVqz2clr5 18A6stx2in0MKueYEhAtESq1oYGTHSEV7GXiowFq/Gj7mHy30I4RVXqoOGEsAi/I Rv7G+zRfk9cm2o+2lug8+PirYnYK7Zslrd5t8/7LhS8zIuHCNXQCCs42EMPJ8rPH 5GzQk6keDqlZxFBaIxSk6Ni2NDIiCWkcUce3vrupTsOqfyJGpRyuUnR6Hn2S73kV C2zHD+QyHrNRRdpD/yR355LbiVRVqok26abE4s4ldgthv7kacTNjkBdNWnLXEU2z iScoVsL7mkrhLtWSOtY5665f/lcAgtvkoO6F6WEt3Hw0dSCxDkHaYnPAfZAiZWi+ bFpmL98HcGMH+dObBWIQupAOFPO/prrf1nwYVSBTK4se5NZghcdVjAu1Sf3m+tVo 9hWYWaa0Knp0/RGxZ90Aj6tb6mJ9/X53wLG0wgZYWqiCoMYmwO2APKepgrjhwVMF wqfbwFArOE+HLotLOiqi =J1br -----END PGP SIGNATURE----- --JU1P3uBe1BU9Y2xT--
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