From owner-svn-src-all@FreeBSD.ORG Wed Jun 22 02:30:08 2011 Return-Path: Delivered-To: svn-src-all@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 6183010656B2; Wed, 22 Jun 2011 02:30:08 +0000 (UTC) (envelope-from imp@bsdimp.com) Received: from harmony.bsdimp.com (bsdimp.com [199.45.160.85]) by mx1.freebsd.org (Postfix) with ESMTP id 48EC48FC08; Wed, 22 Jun 2011 02:30:05 +0000 (UTC) Received: from [10.0.0.63] (63.imp.bsdimp.com [10.0.0.63]) (authenticated bits=0) by harmony.bsdimp.com (8.14.4/8.14.3) with ESMTP id p5M2RGIj084486 (version=TLSv1/SSLv3 cipher=DHE-DSS-AES128-SHA bits=128 verify=NO); Tue, 21 Jun 2011 20:27:21 -0600 (MDT) (envelope-from imp@bsdimp.com) Mime-Version: 1.0 (Apple Message framework v1084) From: Warner Losh In-Reply-To: <4E0128FF.6020804@rice.edu> Date: Tue, 21 Jun 2011 20:27:03 -0600 Message-Id: References: <201106191913.p5JJDOqJ006272@svn.freebsd.org> <20110622063258.D2275@besplex.bde.org> <4E0128FF.6020804@rice.edu> To: Alan Cox X-Mailer: Apple Mail (2.1084) X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.0.1 (harmony.bsdimp.com [10.0.0.6]); Tue, 21 Jun 2011 20:27:21 -0600 (MDT) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: src-committers@FreeBSD.org, Alan Cox , svn-src-all@FreeBSD.org, Attilio Rao , "Bjoern A. Zeeb" , Bruce Evans , svn-src-head@FreeBSD.org Subject: Re: svn commit: r223307 - head/sys/vm X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 22 Jun 2011 02:30:08 -0000 On Jun 21, 2011, at 5:27 PM, Alan Cox wrote: > On 06/21/2011 16:09, Attilio Rao wrote: >> 2011/6/21 Bruce Evans: >>> On Tue, 21 Jun 2011, Bjoern A. Zeeb wrote: >>>=20 >>>> On Jun 19, 2011, at 7:13 PM, Alan Cox wrote: >>>>=20 >>>> Hi Alan, >>>>=20 >>>>> Author: alc >>>>> Date: Sun Jun 19 19:13:24 2011 >>>>> New Revision: 223307 >>>>> URL: http://svn.freebsd.org/changeset/base/223307 >>>>>=20 >>>>> Log: >>>>> Precisely document the synchronization rules for the page's dirty = field. >>>>> (Saying that the lock on the object that the page belongs to must = be >>>>> held >>>>> only represents one aspect of the rules.) >>>>>=20 >>>>> Eliminate the use of the page queues lock for atomically = performing >>>>> read- >>>>> modify-write operations on the dirty field when the underlying >>>>> architecture >>>>> supports atomic operations on char and short types. >>>>>=20 >>>>> Document the fact that 32KB pages aren't really supported. >>>> contrary to the tinderbox I'd like to point out that all mips = kernels >>>> built by universe are broken with a SVN HEAD from earlier today. = Could you >>>> please check and see if you can fix it? The errors I get are: >>>>=20 >>>> vm_page.o: In function `vm_page_clear_dirty': >>>> /sys/vm/vm_page.c:(.text+0x18d0): undefined reference to = `atomic_clear_8' >>>> /sys/vm/vm_page.c:(.text+0x18d0): relocation truncated to fit: = R_MIPS_26 >>>> against `atomic_clear_8' >>>> vm_page.o: In function `vm_page_set_validclean': >>>> /sys/vm/vm_page.c:(.text+0x38f0): undefined reference to = `atomic_clear_8' >>>> /sys/vm/vm_page.c:(.text+0x38f0): relocation truncated to fit: = R_MIPS_26 >>>> against `atomic_clear_8' >>> Atomic types shorter than int cannot be used in MI code, since they = might >>> not exist. Apparently they don't exist on mips. jake@ fixed all = their >>> old uses for sparc4 in ~Y2K. >> I'm sure they do, they exist in support.S though and may not have the >> _8 form (they may just have the _char version). I may look at the = code >> again to be sure. >>=20 >=20 > It appears that while mips/include/atomic.h declares the existence of = atomic_clear_8, mips/mips/support.S doesn't implement it. In other = words, only support for int's and short's is currently implemented, not = char's: >=20 > # grep atomic_clear mips/mips/support.S > * atomic_clear_32(u_int32_t *a, u_int32_t b) > LEAF(atomic_clear_32) > END(atomic_clear_32) > * atomic_clear_16(u_int16_t *a, u_int16_t b) > LEAF(atomic_clear_16) > END(atomic_clear_16) The current crop of atomic*16 and atomic*8 functions have the = restriction that the address must be 32-bit aligned (and it forces this = by aligning to 32-bits silently and then operates on the low 8 or 16 = bits in that word!) I'm guessing that this is likely just wrong. Comments? Warner