Re: [Patch v4 05/12] memory-hotplug: introduce new function arch_remove_memory() for removing page table depends on architecture
From: Tang Chen <hidden>
Date: 2012-12-04 09:31:57
Also in:
linux-acpi, linux-mm, linux-s390, linux-sh, lkml, sparclinux
On 11/27/2012 06:00 PM, Wen Congyang wrote:
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For removing memory, we need to remove page table. But it depends on architecture. So the patch introduce arch_remove_memory() for removing page table. Now it only calls __remove_pages(). Note: __remove_pages() for some archtecuture is not implemented (I don't know how to implement it for s390). CC: David Rientjes<rientjes@google.com> CC: Jiang Liu<redacted> CC: Len Brown<redacted> CC: Benjamin Herrenschmidt<benh@kernel.crashing.org> CC: Paul Mackerras<redacted> CC: Christoph Lameter<redacted> Cc: Minchan Kim<redacted> CC: Andrew Morton<akpm@linux-foundation.org> CC: KOSAKI Motohiro<redacted> CC: Yasuaki Ishimatsu<redacted> Signed-off-by: Wen Congyang<redacted> --- arch/ia64/mm/init.c | 18 ++++++++++++++++++ arch/powerpc/mm/mem.c | 12 ++++++++++++ arch/s390/mm/init.c | 12 ++++++++++++ arch/sh/mm/init.c | 17 +++++++++++++++++ arch/tile/mm/init.c | 8 ++++++++ arch/x86/mm/init_32.c | 12 ++++++++++++ arch/x86/mm/init_64.c | 15 +++++++++++++++ include/linux/memory_hotplug.h | 1 + mm/memory_hotplug.c | 2 ++ 9 files changed, 97 insertions(+)diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c index 082e383..e333822 100644 --- a/arch/ia64/mm/init.c +++ b/arch/ia64/mm/init.c@@ -689,6 +689,24 @@ int arch_add_memory(int nid, u64 start, u64 size) return ret; } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + unsigned long start_pfn = start>> PAGE_SHIFT; + unsigned long nr_pages = size>> PAGE_SHIFT; + struct zone *zone; + int ret; + + zone = page_zone(pfn_to_page(start_pfn)); + ret = __remove_pages(zone, start_pfn, nr_pages); + if (ret) + pr_warn("%s: Problem encountered in __remove_pages() as" + " ret=%d\n", __func__, ret); + + return ret;
Just a little question, why do we have different handlers for ret on different platforms ? Sometimes we print a msg, sometimes we just return, and sometimes we give a WARN_ON(). But no big deal. :) Reviewed-by: Tang Chen <redacted>
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+} +#endif #endif /*diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index 0dba506..09c6451 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c@@ -133,6 +133,18 @@ int arch_add_memory(int nid, u64 start, u64 size) return __add_pages(nid, zone, start_pfn, nr_pages); } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + unsigned long start_pfn = start>> PAGE_SHIFT; + unsigned long nr_pages = size>> PAGE_SHIFT; + struct zone *zone; + + zone = page_zone(pfn_to_page(start_pfn)); + return __remove_pages(zone, start_pfn, nr_pages); +} +#endif #endif /* CONFIG_MEMORY_HOTPLUG */ /*diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 81e596c..b565190 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c@@ -257,4 +257,16 @@ int arch_add_memory(int nid, u64 start, u64 size) vmem_remove_mapping(start, size); return rc; } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + /* + * There is no hardware or firmware interface which could trigger a + * hot memory remove on s390. So there is nothing that needs to be + * implemented. + */ + return -EBUSY; +} +#endif #endif /* CONFIG_MEMORY_HOTPLUG */diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c index 82cc576..1057940 100644 --- a/arch/sh/mm/init.c +++ b/arch/sh/mm/init.c@@ -558,4 +558,21 @@ int memory_add_physaddr_to_nid(u64 addr) EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid); #endif +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + unsigned long start_pfn = start>> PAGE_SHIFT; + unsigned long nr_pages = size>> PAGE_SHIFT; + struct zone *zone; + int ret; + + zone = page_zone(pfn_to_page(start_pfn)); + ret = __remove_pages(zone, start_pfn, nr_pages); + if (unlikely(ret)) + pr_warn("%s: Failed, __remove_pages() == %d\n", __func__, + ret); + + return ret; +} +#endif #endif /* CONFIG_MEMORY_HOTPLUG */diff --git a/arch/tile/mm/init.c b/arch/tile/mm/init.c index ef29d6c..2749515 100644 --- a/arch/tile/mm/init.c +++ b/arch/tile/mm/init.c@@ -935,6 +935,14 @@ int remove_memory(u64 start, u64 size) { return -EINVAL; } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + /* TODO */ + return -EBUSY; +} +#endif #endif struct kmem_cache *pgd_cache;diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index 11a5800..b19eba4 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c@@ -839,6 +839,18 @@ int arch_add_memory(int nid, u64 start, u64 size) return __add_pages(nid, zone, start_pfn, nr_pages); } + +#ifdef CONFIG_MEMORY_HOTREMOVE +int arch_remove_memory(u64 start, u64 size) +{ + unsigned long start_pfn = start>> PAGE_SHIFT; + unsigned long nr_pages = size>> PAGE_SHIFT; + struct zone *zone; + + zone = page_zone(pfn_to_page(start_pfn)); + return __remove_pages(zone, start_pfn, nr_pages); +} +#endif #endif /*diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 3baff25..5675335 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c@@ -680,6 +680,21 @@ int arch_add_memory(int nid, u64 start, u64 size) } EXPORT_SYMBOL_GPL(arch_add_memory); +#ifdef CONFIG_MEMORY_HOTREMOVE +int __ref arch_remove_memory(u64 start, u64 size) +{ + unsigned long start_pfn = start>> PAGE_SHIFT; + unsigned long nr_pages = size>> PAGE_SHIFT; + struct zone *zone; + int ret; + + zone = page_zone(pfn_to_page(start_pfn)); + ret = __remove_pages(zone, start_pfn, nr_pages); + WARN_ON_ONCE(ret); + + return ret; +} +#endif #endif /* CONFIG_MEMORY_HOTPLUG */ static struct kcore_list kcore_vsyscall;diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 38675e9..191b2d9 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h@@ -85,6 +85,7 @@ extern void __online_page_free(struct page *page); #ifdef CONFIG_MEMORY_HOTREMOVE extern bool is_pageblock_removable_nolock(struct page *page); +extern int arch_remove_memory(u64 start, u64 size); #endif /* CONFIG_MEMORY_HOTREMOVE */ /* reasonably generic interface to expand the physical pages in a zone */diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 63d5388..e741732 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c@@ -1111,6 +1111,8 @@ repeat: /* remove memmap entry */ firmware_map_remove(start, start + size, "System RAM"); + arch_remove_memory(start, size); + unlock_memory_hotplug(); return 0;