Date: Fri, 9 Aug 2013 13:40:10 -0700 From: Alan Cox <alc@rice.edu> To: Alan Cox <alc@rice.edu> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, "David E. O'Brien" <obrien@freebsd.org>, John Baldwin <jhb@freebsd.org> Subject: Re: svn commit: r254150 - head/sys/vm Message-ID: <655524DF-4DE9-428C-8A6A-C1A395489EF5@rice.edu> In-Reply-To: <DA97389E-DAB5-4DB6-BB52-417CDBBB0BF9@rice.edu> References: <201308091643.r79GhoWx023884@svn.freebsd.org> <201308091556.47535.jhb@freebsd.org> <DA97389E-DAB5-4DB6-BB52-417CDBBB0BF9@rice.edu>
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On Aug 9, 2013, at 1:34 PM, Alan Cox wrote: > > On Aug 9, 2013, at 12:56 PM, John Baldwin wrote: > >> On Friday, August 09, 2013 12:43:50 pm David E. O'Brien wrote: >>> Author: obrien >>> Date: Fri Aug 9 16:43:50 2013 >>> New Revision: 254150 >>> URL: http://svnweb.freebsd.org/changeset/base/254150 >>> >>> Log: >>> Add missing 'VPO_BUSY' from r254141 to fix kernel build break. >>> >>> Modified: >>> head/sys/vm/vm_page.h >> >> This can't possibly be correct as r254138 just removed this flag. If it isn't >> obvious how to fix the uses added back in r254141, then r254141 should be >> reverted instead. >> >> Hmm, looking at the relevant bits of r254141, it doesn't look obvious: >> >> + /* Detach the old page from the resident tailq. */ >> + TAILQ_REMOVE(&object->memq, mold, listq); >> + vm_page_lock(mold); > > Replace the next four lines with > > vm_page_xunbusy(mold); > On second thought, no, because it could lead to lock recursion. >> + if (mold->oflags & VPO_BUSY) { >> + mold->oflags &= ~VPO_BUSY; >> + vm_page_flash(mold); >> + } >> >> Since nothing is setting this flag, this can't possibly work correctly >> currently. I wouldn't boot a top-of-tree kernel right now. :( >> >> -- >> John Baldwin >> > >
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