From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keith Packard Subject: Re: [PATCH 2/2] drm/i915: properly prefault for pread/pwrite Date: Thu, 03 Nov 2011 14:06:55 -0700 Message-ID: References: <1317203844-2930-1-git-send-email-daniel.vetter@ffwll.ch> <1317203844-2930-2-git-send-email-daniel.vetter@ffwll.ch> <20111023101830.GE2953@phenom.ffwll.local> <20111023221157.GH2953@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1800650817==" Return-path: Received: from keithp.com (home.keithp.com [63.227.221.253]) by gabe.freedesktop.org (Postfix) with ESMTP id EF8529E7DB for ; Thu, 3 Nov 2011 14:07:04 -0700 (PDT) In-Reply-To: <20111023221157.GH2953@phenom.ffwll.local> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org Errors-To: intel-gfx-bounces+gcfxdi-intel-gfx=m.gmane.org@lists.freedesktop.org To: Daniel Vetter Cc: Daniel Vetter , intel-gfx , linux-kernel , "Morton, Andrew" , stable@kernel.org List-Id: intel-gfx@lists.freedesktop.org --===============1800650817== Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" --=-=-= Content-Transfer-Encoding: quoted-printable On Mon, 24 Oct 2011 00:11:57 +0200, Daniel Vetter wrote: > This patch only fixes things up so that we prefault the entire page range > and not just the first PAGE_SIZE bytes (i.e. at most 2 pages). So I don't > see the risk of extending the current behaviour to all pages. Userspace > can already see these zero writes, but only when doing something stupid. When we posted a patch to instead fix fault_in_pages_writeable, Andrew complained that we'd have modified memory even on a short read, which wasn't considered polite. Could we read/write the same value and avoid that problem? Also, we should be fixing fault_in_pages_* going forward, rather than kludging in more code. And, we'd get to remove the version in ntfs, which should end in a patch that removes more code than it adds... =2D-=20 keith.packard@intel.com --=-=-= Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) iQIVAwUBTrMCbzYtFsjWk68qAQgrfRAAsCZyxc9aaWTYWh6nm0TFXUiSbe3mhIRn p1l3BgsiJ+ATp53HaCFSHgG54HGNk3bxnMiUGeWg9K79UHnf8CAE3ZGWJyJmzS+t 1UOhy0lWtLl3UHmujk6jFPNgoqsAkP0KCZHXkfDr8s17JWWf5Az5kFFUg7gIzSEQ FKdQ5EMlVX+Y/yWdMIzwqCjI4UV/tKmShRDWHT64olYERFzCppOfM6SoXLijmyhV jTXTG92K2r1dw44YBDTonEVjqThaHE+rsKkVyHeZavTt3xQ1b2ug80Cv4nnbThdV swjwCpaCs7KElVRnurqJplQQWWDNVRwTRvKNzCau2D1Ji3klOTPZUZ8Xm4w2n5eP qYzerWSlEuCm/yD5eGLAD+pVBxcxltrXGTfFLtzjD4AfPCR9Bvdb4bntUgBrN4OC HmavzwPeHU6e965mHgxqWr+ZQcaFr0FG1ukEueiqbmZJi8pJYZwlkcjswMrvW/Xs y+IHyFuDYcXq9spUXEcSaz7FkL57KIwtLov98nHYvKIHTiM0ssz02ajZpcr1JLXX PPLIAAm6X8+3HrhS7Nffl4RMKQQq6xk3RqNGH86aXIwqSL1azjZMO+QsMmAaH+zI MPz+IVjRoNJF57FwwlyrmpGReIYEq+88wU1JDjr2pd8/p66Tr+U61m328P1P/07u 6w636prxbKA= =gH6w -----END PGP SIGNATURE----- --=-=-=-- --===============1800650817== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/intel-gfx --===============1800650817==--