Messages in this thread Patch in this message | | | Date | Sun, 6 Dec 2009 11:46:36 +0800 | From | Wu Fengguang <> | Subject | [RFC] print symbolic page flag names in bad_page() |
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Hi Alex,
On Sat, Dec 05, 2009 at 05:29:48AM +0800, Alex Chiang wrote: [...] > Teach page-types the -k mode, which parses and describes the bits in > the internal kernel order: > > # ./Documentation/vm/page-types -k 0x4000 > 0x0000000000004000 ______________H_________ compound_head [...] > The implication is that attempting to use page-types -k on a kernel > with different CONFIG_* settings may lead to surprising and misleading > results. To retain sanity, always use the page-types built out of the > kernel tree you are actually testing.
This is useful feature, however not as convenient if the kernel can print its page flag names directly :) (especially when the dmesg comes from some end user)
So how about this patch? ---
mm: introduce dump_page()
- introduce dump_page() to print the page info for debugging some error condition. - print an extra field: the symbolic names of page->flags - convert three mm users: bad_page(), print_bad_pte() and memory offline failure.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> --- mm/internal.h | 2 + mm/memory.c | 8 +--- mm/memory_hotplug.c | 6 +-- mm/page_alloc.c | 75 +++++++++++++++++++++++++++++++++++++++--- 4 files changed, 78 insertions(+), 13 deletions(-)
--- linux-mm.orig/mm/page_alloc.c 2009-12-06 10:11:08.000000000 +0800 +++ linux-mm/mm/page_alloc.c 2009-12-06 11:22:58.000000000 +0800 @@ -48,6 +48,7 @@ #include <linux/page_cgroup.h> #include <linux/debugobjects.h> #include <linux/kmemleak.h> +#include <linux/kernel-page-flags.h> #include <trace/events/kmem.h> #include <asm/tlbflush.h> @@ -262,10 +263,7 @@ static void bad_page(struct page *page) printk(KERN_ALERT "BUG: Bad page state in process %s pfn:%05lx\n", current->comm, page_to_pfn(page)); - printk(KERN_ALERT - "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n", - page, (void *)page->flags, page_count(page), - page_mapcount(page), page->mapping, page->index); + dump_page(page); dump_stack(); out: @@ -5106,3 +5104,72 @@ bool is_free_buddy_page(struct page *pag return order < MAX_ORDER; } #endif + +static char *page_flag_names[] = { + [KPF_LOCKED] = "L:locked", + [KPF_ERROR] = "E:error", + [KPF_REFERENCED] = "R:referenced", + [KPF_UPTODATE] = "U:uptodate", + [KPF_DIRTY] = "D:dirty", + [KPF_LRU] = "l:lru", + [KPF_ACTIVE] = "A:active", + [KPF_SLAB] = "S:slab", + [KPF_WRITEBACK] = "W:writeback", + [KPF_RECLAIM] = "I:reclaim", + [KPF_BUDDY] = "B:buddy", + + [KPF_MMAP] = "M:mmap", + [KPF_ANON] = "a:anonymous", + [KPF_SWAPCACHE] = "s:swapcache", + [KPF_SWAPBACKED] = "b:swapbacked", + [KPF_COMPOUND_HEAD] = "H:compound_head", + [KPF_COMPOUND_TAIL] = "T:compound_tail", + [KPF_HUGE] = "G:huge", + [KPF_UNEVICTABLE] = "u:unevictable", + [KPF_HWPOISON] = "X:hwpoison", + [KPF_NOPAGE] = "n:nopage", + [KPF_KSM] = "V:shared", + + [KPF_RESERVED] = "r:reserved", + [KPF_MLOCKED] = "m:mlocked", + [KPF_MAPPEDTODISK] = "d:mappedtodisk", + [KPF_PRIVATE] = "P:private", + [KPF_PRIVATE_2] = "p:private_2", + [KPF_OWNER_PRIVATE] = "O:owner_private", + [KPF_ARCH] = "h:arch", + [KPF_UNCACHED] = "c:uncached", +}; + +static char *page_flags_longname(struct page *page, char *buf, int buflen) +{ + int i, n; + u64 flags; + + flags = stable_page_flags(page); + + for (i = 0, n = 0; i < ARRAY_SIZE(page_flag_names); i++) { + if (!page_flag_names[i]) + continue; + if ((flags >> i) & 1) + n += snprintf(buf + n, buflen - n, "%s,", + page_flag_names[i] + 2); + } + if (n) + n--; + buf[n] = '\0'; + + return buf; +} + +void dump_page(struct page *page) +{ + char buf[1024]; + + printk(KERN_ALERT + "page:%p flags:%p(%s) count:%d mapcount:%d mapping:%p index:%lx\n", + page, (void *)page->flags, + page_flags_longname(page, buf, sizeof(buf)), + page_count(page), page_mapcount(page), + page->mapping, page->index); +} +EXPORT_SYMBOL(dump_page); --- linux-mm.orig/mm/memory.c 2009-12-06 10:37:47.000000000 +0800 +++ linux-mm/mm/memory.c 2009-12-06 10:57:25.000000000 +0800 @@ -430,12 +430,8 @@ static void print_bad_pte(struct vm_area "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", current->comm, (long long)pte_val(pte), (long long)pmd_val(*pmd)); - if (page) { - printk(KERN_ALERT - "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n", - page, (void *)page->flags, page_count(page), - page_mapcount(page), page->mapping, page->index); - } + if (page) + dump_page(page); printk(KERN_ALERT "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n", (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); --- linux-mm.orig/mm/internal.h 2009-12-06 10:47:37.000000000 +0800 +++ linux-mm/mm/internal.h 2009-12-06 11:03:53.000000000 +0800 @@ -264,6 +264,8 @@ int __get_user_pages(struct task_struct #define ZONE_RECLAIM_SUCCESS 1 #endif +void dump_page(struct page *page); + extern int hwpoison_filter(struct page *p); extern u32 hwpoison_filter_dev_major; --- linux-mm.orig/mm/memory_hotplug.c 2009-12-06 11:01:20.000000000 +0800 +++ linux-mm/mm/memory_hotplug.c 2009-12-06 11:01:23.000000000 +0800 @@ -678,9 +678,9 @@ do_migrate_range(unsigned long start_pfn if (page_count(page)) not_managed++; #ifdef CONFIG_DEBUG_VM - printk(KERN_INFO "removing from LRU failed" - " %lx/%d/%lx\n", - pfn, page_count(page), page->flags); + printk(KERN_INFO "removing pfn %lx from LRU failed\n", + pfn); + dump_page(page); #endif } }
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