From: Alexander Nyberg Introduces CONFIG_PAGE_OWNER that keeps track of the call chain under which a page was allocated. Includes a user-space helper in Documentation/page_owner.c to sort the enormous amount of output that this may give (thanks tridge). Information available through /proc/page_owner x86_64 introduces some stack noise in certain call chains so for exact output use of x86 && CONFIG_FRAME_POINTER is suggested. Tested on x86, x86 && CONFIG_FRAME_POINTER, x86_64 Output looks like: 4819 times: Page allocated via order 0, mask 0x50 [0xc012b7b9] find_lock_page+25 [0xc012b8c8] find_or_create_page+152 [0xc0147d74] grow_dev_page+36 [0xc0148164] __find_get_block+84 [0xc0147ebc] __getblk_slow+124 [0xc0148164] __find_get_block+84 [0xc01481e7] __getblk+55 [0xc0185d14] do_readahead+100 We use a custom stack unwinder because using __builtin_return_address([0-7]) causes gcc to generate code that might try to unwind the stack looking for function return addresses and "fall off" causing early panics if the call chain is not deep enough. So in that case we could have had a depth of around 3 functions in all traces (I experimented a bit with this). From: Dave Hansen make page_owner handle non-contiguous page ranges From: Alexander Nyberg I've cleaned up the __alloc_pages() part to a simple set_page_owner() call. Signed-off-by: Alexander Nyberg Signed-off-by: Dave Hansen Signed-Off-by: Kamezawa Hiroyuki DESC Update page->order at an appropriate time when tracking PAGE_OWNER EDESC From: mel@skynet.ie (Mel Gorman) PAGE_OWNER tracks free pages by setting page->order to -1. However, it is set during __free_pages() which is not the only free path as __pagevec_free() and free_compound_page() do not go through __free_pages(). This leads to a situation where free pages are visible in /proc/page_owner which is confusing and might be interpreted as a memory leak. This patch sets page->owner when PageBuddy is set. It also prints a warning to the kernel log if a free page is found that does not appear free to PAGE_OWNER. This should be considered a fix to page-owner-tracking-leak-detector.patch. This only applies to -mm as PAGE_OWNER is not in mainline. Signed-off-by: Mel Gorman Acked-by: Andy Whitcroft DESC Print out PAGE_OWNER statistics in relation to fragmentation avoidance EDESC From: Mel Gorman When PAGE_OWNER is set, more information is available of relevance to fragmentation avoidance. A second line is added to /proc/page_owner showing the PFN, the pageblock number, the mobility type of the page based on its allocation flags, whether the allocation is improperly placed and the flags. A sample entry looks like Page allocated via order 0, mask 0x1280d2 PFN 7355 Block 7 type 3 Fallback Flags LA [0xc01528c6] __handle_mm_fault+598 [0xc0320427] do_page_fault+279 [0xc031ed9a] error_code+114 This information can be used to identify pages that are improperly placed. As the format of PAGE_OWNER data is now different, the comment at the top of Documentation/page_owner.c is updated with new instructions. As PAGE_OWNER tracks the GFP flags used to allocate the pages, /proc/pagetypeinfo is enhanced to contain how many mixed blocks exist. The additional output looks like Number of mixed blocks Unmovable Reclaimable Movable Reserve Node 0, zone DMA 0 1 2 1 Node 0, zone Normal 2 11 33 0 Signed-off-by: Mel Gorman Acked-by: Andy Whitcroft Acked-by: Christoph Lameter DESC Allow PAGE_OWNER to be set on any architecture EDESC From: Mel Gorman Currently PAGE_OWNER depends on CONFIG_X86. This appears to be due to pfn_to_page() being called in an inappropriate for many memory models and the presense of memory holes. This patch ensures that pfn_valid() and pfn_valid_within() is called at the appropriate places and the offsets correctly updated so that PAGE_OWNER is safe on any architecture. In situations where CONFIG_HOLES_IN_ZONES is set (IA64 with VIRTUAL_MEM_MAP), there may be cases where pages allocated within a MAX_ORDER_NR_PAGES block of pages may not be displayed in /proc/page_owner if the hole is at the start of the block. Addressing this would be quite complex, perform slowly and is of no clear benefit. Once PAGE_OWNER is allowed on all architectures, the statistics for grouping pages by mobility that declare how many pageblocks contain mixed page types becomes optionally available on all arches. This patch was tested successfully on x86, x86_64, ppc64 and IA64 machines. Signed-off-by: Mel Gorman Acked-by: Andy Whitcroft DESC allow-page_owner-to-be-set-on-any-architecture-fix EDESC From: Andrew Morton Cc: Andy Whitcroft Cc: Mel Gorman DESC allow-page_owner-to-be-set-on-any-architecture-fix fix EDESC From: mel@skynet.ie (Mel Gorman) Page-owner-tracking stores the a backtrace of an allocation in the struct page. How the stack trace is generated depends on whether CONFIG_FRAME_POINTER is set or not. If CONFIG_FRAME_POINTER is set, the frame pointer must be read using some inline assembler which is not available for all architectures. This patch uses the frame pointer where it is available but has a fallback where it is not. Signed-off-by: Mel Gorman Cc: Andy Whitcroft Signed-off-by: Andrew Morton --- Documentation/page_owner.c | 141 ++++++++++++++++++++++++++++++++++ fs/proc/proc_misc.c | 145 +++++++++++++++++++++++++++++++++++ include/linux/mm_types.h | 5 + lib/Kconfig.debug | 10 ++ mm/page_alloc.c | 66 +++++++++++++++ mm/vmstat.c | 93 ++++++++++++++++++++++ 6 files changed, 460 insertions(+) diff -puN /dev/null Documentation/page_owner.c --- /dev/null +++ a/Documentation/page_owner.c @@ -0,0 +1,141 @@ +/* + * User-space helper to sort the output of /proc/page_owner + * + * Example use: + * cat /proc/page_owner > page_owner_full.txt + * grep -v ^PFN page_owner_full.txt > page_owner.txt + * ./sort page_owner.txt sorted_page_owner.txt +*/ + +#include +#include +#include +#include +#include +#include +#include + +struct block_list { + char *txt; + int len; + int num; +}; + + +static struct block_list *list; +static int list_size; +static int max_size; + +struct block_list *block_head; + +int read_block(char *buf, FILE *fin) +{ + int ret = 0; + int hit = 0; + char *curr = buf; + + for (;;) { + *curr = getc(fin); + if (*curr == EOF) return -1; + + ret++; + if (*curr == '\n' && hit == 1) + return ret - 1; + else if (*curr == '\n') + hit = 1; + else + hit = 0; + curr++; + } +} + +static int compare_txt(struct block_list *l1, struct block_list *l2) +{ + return strcmp(l1->txt, l2->txt); +} + +static int compare_num(struct block_list *l1, struct block_list *l2) +{ + return l2->num - l1->num; +} + +static void add_list(char *buf, int len) +{ + if (list_size != 0 && + len == list[list_size-1].len && + memcmp(buf, list[list_size-1].txt, len) == 0) { + list[list_size-1].num++; + return; + } + if (list_size == max_size) { + printf("max_size too small??\n"); + exit(1); + } + list[list_size].txt = malloc(len+1); + list[list_size].len = len; + list[list_size].num = 1; + memcpy(list[list_size].txt, buf, len); + list[list_size].txt[len] = 0; + list_size++; + if (list_size % 1000 == 0) { + printf("loaded %d\r", list_size); + fflush(stdout); + } +} + +int main(int argc, char **argv) +{ + FILE *fin, *fout; + char buf[1024]; + int ret, i, count; + struct block_list *list2; + struct stat st; + + fin = fopen(argv[1], "r"); + fout = fopen(argv[2], "w"); + if (!fin || !fout) { + printf("Usage: ./program \n"); + perror("open: "); + exit(2); + } + + fstat(fileno(fin), &st); + max_size = st.st_size / 100; /* hack ... */ + + list = malloc(max_size * sizeof(*list)); + + for(;;) { + ret = read_block(buf, fin); + if (ret < 0) + break; + + buf[ret] = '\0'; + add_list(buf, ret); + } + + printf("loaded %d\n", list_size); + + printf("sorting ....\n"); + + qsort(list, list_size, sizeof(list[0]), compare_txt); + + list2 = malloc(sizeof(*list) * list_size); + + printf("culling\n"); + + for (i=count=0;i +#include +static ssize_t +read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) +{ + unsigned long pfn; + struct page *page; + char *kbuf, *modname; + const char *symname; + int ret = 0; + char namebuf[128]; + unsigned long offset = 0, symsize; + int i; + ssize_t num_written = 0; + int blocktype = 0, pagetype = 0; + + page = NULL; + pfn = min_low_pfn + *ppos; + + /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ + while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) + pfn++; + + /* Find an allocated page */ + for (; pfn < max_pfn; pfn++) { + /* + * If the new page is in a new MAX_ORDER_NR_PAGES area, + * validate the area as existing, skip it if not + */ + if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) { + pfn += MAX_ORDER_NR_PAGES - 1; + continue; + } + + /* Check for holes within a MAX_ORDER area */ + if (!pfn_valid_within(pfn)) + continue; + + page = pfn_to_page(pfn); + + /* Catch situations where free pages have a bad ->order */ + if (page->order >= 0 && PageBuddy(page)) + printk(KERN_WARNING + "PageOwner info inaccurate for PFN %lu\n", + pfn); + + /* Stop search if page is allocated and has trace info */ + if (page->order >= 0 && page->trace[0]) + break; + } + + if (!pfn_valid(pfn)) + return 0; + + /* Record the next PFN to read in the file offset */ + *ppos = (pfn - min_low_pfn) + 1; + + kbuf = kmalloc(count, GFP_KERNEL); + if (!kbuf) + return -ENOMEM; + + ret = snprintf(kbuf, count, "Page allocated via order %d, mask 0x%x\n", + page->order, page->gfp_mask); + if (ret >= count) { + ret = -ENOMEM; + goto out; + } + + /* Print information relevant to grouping pages by mobility */ + blocktype = get_pageblock_migratetype(page); + pagetype = allocflags_to_migratetype(page->gfp_mask); + ret += snprintf(kbuf+ret, count-ret, + "PFN %lu Block %lu type %d %s " + "Flags %s%s%s%s%s%s%s%s%s%s%s%s\n", + pfn, + pfn >> pageblock_order, + blocktype, + blocktype != pagetype ? "Fallback" : " ", + PageLocked(page) ? "K" : " ", + PageError(page) ? "E" : " ", + PageReferenced(page) ? "R" : " ", + PageUptodate(page) ? "U" : " ", + PageDirty(page) ? "D" : " ", + PageLRU(page) ? "L" : " ", + PageActive(page) ? "A" : " ", + PageSlab(page) ? "S" : " ", + PageWriteback(page) ? "W" : " ", + PageCompound(page) ? "C" : " ", + PageSwapCache(page) ? "B" : " ", + PageMappedToDisk(page) ? "M" : " "); + if (ret >= count) { + ret = -ENOMEM; + goto out; + } + + num_written = ret; + + for (i = 0; i < 8; i++) { + if (!page->trace[i]) + break; + symname = kallsyms_lookup(page->trace[i], &symsize, &offset, + &modname, namebuf); + ret = snprintf(kbuf + num_written, count - num_written, + "[0x%lx] %s+%lu\n", + page->trace[i], namebuf, offset); + if (ret >= count - num_written) { + ret = -ENOMEM; + goto out; + } + num_written += ret; + } + + ret = snprintf(kbuf + num_written, count - num_written, "\n"); + if (ret >= count - num_written) { + ret = -ENOMEM; + goto out; + } + + num_written += ret; + ret = num_written; + + if (copy_to_user(buf, kbuf, ret)) + ret = -EFAULT; +out: + kfree(kbuf); + return ret; +} + +static struct file_operations proc_page_owner_operations = { + .read = read_page_owner, +}; +#endif + struct proc_dir_entry *proc_root_kcore; void __init proc_misc_init(void) @@ -907,4 +1041,15 @@ void __init proc_misc_init(void) #ifdef CONFIG_MAGIC_SYSRQ proc_create("sysrq-trigger", S_IWUSR, NULL, &proc_sysrq_trigger_operations); #endif +#ifdef CONFIG_PAGE_OWNER + { + struct proc_dir_entry *entry; + entry = create_proc_entry("page_owner", + S_IWUSR | S_IRUGO, NULL); + if (entry) { + entry->proc_fops = &proc_page_owner_operations; + entry->size = 1024; + } + } +#endif } diff -puN include/linux/mm_types.h~page-owner-tracking-leak-detector include/linux/mm_types.h --- a/include/linux/mm_types.h~page-owner-tracking-leak-detector +++ a/include/linux/mm_types.h @@ -94,6 +94,11 @@ struct page { #ifdef CONFIG_CGROUP_MEM_RES_CTLR unsigned long page_cgroup; #endif +#ifdef CONFIG_PAGE_OWNER + int order; + unsigned int gfp_mask; + unsigned long trace[8]; +#endif }; /* diff -puN lib/Kconfig.debug~page-owner-tracking-leak-detector lib/Kconfig.debug --- a/lib/Kconfig.debug~page-owner-tracking-leak-detector +++ a/lib/Kconfig.debug @@ -66,6 +66,16 @@ config UNUSED_SYMBOLS you really need it, and what the merge plan to the mainline kernel for your module is. +config PAGE_OWNER + bool "Track page owner" + depends on DEBUG_KERNEL + help + This keeps track of what call chain is the owner of a page, may + help to find bare alloc_page(s) leaks. Eats a fair amount of memory. + See Documentation/page_owner.c for user-space helper. + + If unsure, say N. + config DEBUG_FS bool "Debug Filesystem" depends on SYSFS diff -puN mm/page_alloc.c~page-owner-tracking-leak-detector mm/page_alloc.c --- a/mm/page_alloc.c~page-owner-tracking-leak-detector +++ a/mm/page_alloc.c @@ -327,6 +327,9 @@ static inline void set_page_order(struct { set_page_private(page, order); __SetPageBuddy(page); +#ifdef CONFIG_PAGE_OWNER + page->order = -1; +#endif } static inline void rmv_page_order(struct page *page) @@ -1455,6 +1458,62 @@ try_next_zone: return page; } +#ifdef CONFIG_PAGE_OWNER +static inline int valid_stack_ptr(struct thread_info *tinfo, void *p) +{ + return p > (void *)tinfo && + p < (void *)tinfo + THREAD_SIZE - 3; +} + +static inline void __stack_trace(struct page *page, unsigned long *stack, + unsigned long bp) +{ + int i = 0; + unsigned long addr; + struct thread_info *tinfo = (struct thread_info *) + ((unsigned long)stack & (~(THREAD_SIZE - 1))); + + memset(page->trace, 0, sizeof(long) * 8); + +#ifdef CONFIG_FRAME_POINTER + if (bp) { + while (valid_stack_ptr(tinfo, (void *)bp)) { + addr = *(unsigned long *)(bp + sizeof(long)); + page->trace[i] = addr; + if (++i >= 8) + break; + bp = *(unsigned long *)bp; + } + return; + } +#endif /* CONFIG_FRAME_POINTER */ + while (valid_stack_ptr(tinfo, stack)) { + addr = *stack++; + if (__kernel_text_address(addr)) { + page->trace[i] = addr; + if (++i >= 8) + break; + } + } +} + +static void set_page_owner(struct page *page, unsigned int order, + unsigned int gfp_mask) +{ + unsigned long address; + unsigned long bp = 0; +#ifdef CONFIG_X86_64 + asm ("movq %%rbp, %0" : "=r" (bp) : ); +#endif +#ifdef CONFIG_X86_32 + asm ("movl %%ebp, %0" : "=r" (bp) : ); +#endif + page->order = (int) order; + page->gfp_mask = gfp_mask; + __stack_trace(page, &address, bp); +} +#endif /* CONFIG_PAGE_OWNER */ + /* * This is the 'heart' of the zoned buddy allocator. */ @@ -1659,6 +1718,10 @@ nopage: show_mem(); } got_pg: +#ifdef CONFIG_PAGE_OWNER + if (page) + set_page_owner(page, order, gfp_mask); +#endif return page; } EXPORT_SYMBOL(__alloc_pages_internal); @@ -2579,6 +2642,9 @@ void __meminit memmap_init_zone(unsigned if (!is_highmem_idx(zone)) set_page_address(page, __va(pfn << PAGE_SHIFT)); #endif +#ifdef CONFIG_PAGE_OWNER + page->order = -1; +#endif } } diff -puN mm/vmstat.c~page-owner-tracking-leak-detector mm/vmstat.c --- a/mm/vmstat.c~page-owner-tracking-leak-detector +++ a/mm/vmstat.c @@ -15,6 +15,7 @@ #include #include #include +#include "internal.h" #ifdef CONFIG_VM_EVENT_COUNTERS DEFINE_PER_CPU(struct vm_event_state, vm_event_states) = {{0}}; @@ -543,6 +544,97 @@ static int pagetypeinfo_showblockcount(s return 0; } +#ifdef CONFIG_PAGE_OWNER +static void pagetypeinfo_showmixedcount_print(struct seq_file *m, + pg_data_t *pgdat, + struct zone *zone) +{ + int mtype, pagetype; + unsigned long pfn; + unsigned long start_pfn = zone->zone_start_pfn; + unsigned long end_pfn = start_pfn + zone->spanned_pages; + unsigned long count[MIGRATE_TYPES] = { 0, }; + + /* Align PFNs to pageblock_nr_pages boundary */ + pfn = start_pfn & ~(pageblock_nr_pages-1); + + /* + * Walk the zone in pageblock_nr_pages steps. If a page block spans + * a zone boundary, it will be double counted between zones. This does + * not matter as the mixed block count will still be correct + */ + for (; pfn < end_pfn; pfn += pageblock_nr_pages) { + struct page *page; + unsigned long offset = 0; + + /* Do not read before the zone start, use a valid page */ + if (pfn < start_pfn) + offset = start_pfn - pfn; + + if (!pfn_valid(pfn + offset)) + continue; + + page = pfn_to_page(pfn + offset); + mtype = get_pageblock_migratetype(page); + + /* Check the block for bad migrate types */ + for (; offset < pageblock_nr_pages; offset++) { + /* Do not past the end of the zone */ + if (pfn + offset >= end_pfn) + break; + + if (!pfn_valid_within(pfn + offset)) + continue; + + page = pfn_to_page(pfn + offset); + + /* Skip free pages */ + if (PageBuddy(page)) { + offset += (1UL << page_order(page)) - 1UL; + continue; + } + if (page->order < 0) + continue; + + pagetype = allocflags_to_migratetype(page->gfp_mask); + if (pagetype != mtype) { + count[mtype]++; + break; + } + + /* Move to end of this allocation */ + offset += (1 << page->order) - 1; + } + } + + /* Print counts */ + seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name); + for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) + seq_printf(m, "%12lu ", count[mtype]); + seq_putc(m, '\n'); +} +#endif /* CONFIG_PAGE_OWNER */ + +/* + * Print out the number of pageblocks for each migratetype that contain pages + * of other types. This gives an indication of how well fallbacks are being + * contained by rmqueue_fallback(). It requires information from PAGE_OWNER + * to determine what is going on + */ +static void pagetypeinfo_showmixedcount(struct seq_file *m, pg_data_t *pgdat) +{ +#ifdef CONFIG_PAGE_OWNER + int mtype; + + seq_printf(m, "\n%-23s", "Number of mixed blocks "); + for (mtype = 0; mtype < MIGRATE_TYPES; mtype++) + seq_printf(m, "%12s ", migratetype_names[mtype]); + seq_putc(m, '\n'); + + walk_zones_in_node(m, pgdat, pagetypeinfo_showmixedcount_print); +#endif /* CONFIG_PAGE_OWNER */ +} + /* * This prints out statistics in relation to grouping pages by mobility. * It is expensive to collect so do not constantly read the file. @@ -560,6 +652,7 @@ static int pagetypeinfo_show(struct seq_ seq_putc(m, '\n'); pagetypeinfo_showfree(m, pgdat); pagetypeinfo_showblockcount(m, pgdat); + pagetypeinfo_showmixedcount(m, pgdat); return 0; } _