Messages in this thread Patch in this message | | | Date | Mon, 1 Dec 2008 00:46:53 +0000 (GMT) | From | Hugh Dickins <> | Subject | [PATCH 7/8] badpage: ratelimit print_bad_pte and bad_page |
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print_bad_pte() and bad_page() might each need ratelimiting - especially for their dump_stacks, almost never of interest, yet not quite dispensible. Correlating corruption across neighbouring entries can be very helpful, so allow a burst of 60 reports before keeping quiet for the remainder of that minute (or allow a steady drip of one report per second).
Signed-off-by: Hugh Dickins <hugh@veritas.com> ---
mm/memory.c | 23 +++++++++++++++++++++++ mm/page_alloc.c | 26 +++++++++++++++++++++++++- 2 files changed, 48 insertions(+), 1 deletion(-)
--- badpage6/mm/memory.c 2008-11-28 20:40:48.000000000 +0000 +++ badpage7/mm/memory.c 2008-11-28 20:40:50.000000000 +0000 @@ -383,6 +383,29 @@ static void print_bad_pte(struct vm_area pmd_t *pmd = pmd_offset(pud, addr); struct address_space *mapping; pgoff_t index; + static unsigned long resume; + static unsigned long nr_shown; + static unsigned long nr_unshown; + + /* + * Allow a burst of 60 reports, then keep quiet for that minute; + * or allow a steady drip of one report per second. + */ + if (nr_shown == 60) { + if (time_before(jiffies, resume)) { + nr_unshown++; + return; + } + if (nr_unshown) { + printk(KERN_EMERG + "Bad page map: %lu messages suppressed\n", + nr_unshown); + nr_unshown = 0; + } + nr_shown = 0; + } + if (nr_shown++ == 0) + resume = jiffies + 60 * HZ; mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; index = linear_page_index(vma, addr); --- badpage6/mm/page_alloc.c 2008-11-28 20:40:42.000000000 +0000 +++ badpage7/mm/page_alloc.c 2008-11-28 20:40:50.000000000 +0000 @@ -223,6 +223,30 @@ static inline int bad_range(struct zone static void bad_page(struct page *page) { + static unsigned long resume; + static unsigned long nr_shown; + static unsigned long nr_unshown; + + /* + * Allow a burst of 60 reports, then keep quiet for that minute; + * or allow a steady drip of one report per second. + */ + if (nr_shown == 60) { + if (time_before(jiffies, resume)) { + nr_unshown++; + goto out; + } + if (nr_unshown) { + printk(KERN_EMERG + "Bad page state: %lu messages suppressed\n", + nr_unshown); + nr_unshown = 0; + } + nr_shown = 0; + } + if (nr_shown++ == 0) + resume = jiffies + 60 * HZ; + printk(KERN_EMERG "Bad page state in process %s pfn:%05lx\n", current->comm, page_to_pfn(page)); printk(KERN_EMERG @@ -232,7 +256,7 @@ static void bad_page(struct page *page) printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n"); dump_stack(); - +out: /* Leave bad fields for debug, except PageBuddy could make trouble */ __ClearPageBuddy(page); add_taint(TAINT_BAD_PAGE);
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