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Date: Mon, 12 May 2008 17:17:02 -0700 From: Geoff Levand <geoffrey.levand@...sony.com> To: Badari Pulavarty <pbadari@...ibm.com> CC: lkml <linux-kernel@...r.kernel.org>, linuxppc-dev@...abs.org, paulus@...ba.org, Yasunori Goto <y-goto@...fujitsu.com> Subject: Re: [PATCH 5/5] [PPC] provide walk_memory_resource() for ppc Hi, I've had some trouble with this change. Badari Pulavarty wrote: > Provide walk_memory_resource() for ppc64. PPC maintains > logic memory region mapping in lmb.memory structures. Walk > through these structures and do the callbacks for the > contiguous chunks. ... > --- linux-2.6.25-rc3.orig/arch/powerpc/mm/mem.c 2008-03-05 10:14:28.000000000 -0800 > +++ linux-2.6.25-rc3/arch/powerpc/mm/mem.c 2008-03-05 10:32:16.000000000 -0800 > @@ -148,19 +148,35 @@ out: > > /* > * walk_memory_resource() needs to make sure there is no holes in a given > - * memory range. On PPC64, since this range comes from /sysfs, the range > - * is guaranteed to be valid, non-overlapping and can not contain any > - * holes. By the time we get here (memory add or remove), /proc/device-tree > - * is updated and correct. Only reason we need to check against device-tree > - * would be if we allow user-land to specify a memory range through a > - * system call/ioctl etc. instead of doing offline/online through /sysfs. > + * memory range. PPC64 does not maintain the memory layout in /proc/iomem. > + * Instead it maintains it in lmb.memory structures. Walk through the > + * memory regions, find holes and callback for contiguous regions. > */ > int > walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg, > int (*func)(unsigned long, unsigned long, void *)) > { > - return (*func)(start_pfn, nr_pages, arg); > + struct lmb_property res; > + unsigned long pfn, len; > + u64 end; > + int ret = -1; > + > + res.base = (u64) start_pfn << PAGE_SHIFT; > + res.size = (u64) nr_pages << PAGE_SHIFT; > + > + end = res.base + res.size - 1; > + while ((res.base < end) && (lmb_find(&res) >= 0)) { ^^^^^^^^^^^^^^ In the PS3 platform code (arch/pwerpc/platfroms/ps3/mm.c) the hotplug memory is added like this: ... result = add_memory(0, start_addr, map.r1.size); ... result = online_pages(start_pfn, nr_pages); ... In its work, online_pages() eventually calls walk_memory_resource(), which has been changed as above to do a test on lmb_find(). I found that this lmb_find() test always fails for PS3 since add_memory() does not call lmb_add(). Is it the responsibility of the platform code to call lmb_add(), or should that be done by add_memory()? -Geoff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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