Date: Thu, 2 Dec 2010 09:46:03 -0500 From: Andrew Duane <aduane@juniper.net> To: Warner Losh <imp@bsdimp.com>, "freebsd-mips@freebsd.org" <freebsd-mips@freebsd.org>, Alan Cox <alc@cs.rice.edu> Subject: RE: vm_page_startup() Message-ID: <AC6674AB7BC78549BB231821ABF7A9AE9079119F4B@EMBX01-WF.jnpr.net> In-Reply-To: <4CF71F79.3020500@bsdimp.com> References: <4CF5E518.20508@rice.edu>,<4CF71F79.3020500@bsdimp.com>
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I much prefer the latter suggestion: making the code #ifdef'd on a feature,= and having each platform define (or not) the feature. I've seen what happe= ns when code in this space grows too many architecture ifdef's..... -- Andrew Duane Juniper Networks 978-589-0551 10 Technology Park Dr aduane@juniper.net Westford, MA 01886-3418 ________________________________________ From: owner-freebsd-mips@freebsd.org [owner-freebsd-mips@freebsd.org] On Be= half Of Warner Losh [imp@bsdimp.com] Sent: Wednesday, December 01, 2010 11:24 PM To: freebsd-mips@freebsd.org; Alan Cox Subject: Re: vm_page_startup() On 11/30/2010 23:03, Alan Cox wrote: > Given this bit of code in the MIPS pmap: > > vm_offset_t > pmap_map(vm_offset_t *virt, vm_offset_t start, vm_offset_t end, int prot) > { > vm_offset_t va, sva; > > if (MIPS_DIRECT_MAPPABLE(end)) > return (MIPS_PHYS_TO_DIRECT(start)); All mips architectures have at least a small direct map... > The following in vm_page_startup() can apply to MIPS (as well as amd64): > > #ifdef __amd64__ > /* > * pmap_map on amd64 comes out of the direct-map, not kvm like i386, > * so the pages must be tracked for a crashdump to include this data. > * This includes the vm_page_array and the early UMA bootstrap pages. > */ > for (pa =3D new_end; pa < phys_avail[biggestone + 1]; pa +=3D PAGE_SIZ= E) > dump_add_page(pa); > #endif > > Even if a particular MIPS-based machine didn't wind up using the > direct map for the pmap_map calls in vm_page_startup() there would be > no harm in having called dump_add_page(). On the other hand, if you > don't call dump_add_page() when the direct map is used, you're crash > dump will be missing some kernel data structures. So would you suggest having: #if defined(__mips__) || defined(__amd64__) or #if __VM_HAS_DIRECT_MAP and adding that define to pmap.h for mips and amd64? I'm leaning to the latter, since I don't like #ifdef arch in vm/* code on general principles, but you're the maintainer... Warner _______________________________________________ freebsd-mips@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-mips To unsubscribe, send any mail to "freebsd-mips-unsubscribe@freebsd.org"
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