diff options
Diffstat (limited to 'mm/page_owner.c')
| -rw-r--r-- | mm/page_owner.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/mm/page_owner.c b/mm/page_owner.c new file mode 100644 index 000000000000..85eec7ea6735 --- /dev/null +++ b/mm/page_owner.c @@ -0,0 +1,222 @@ +#include <linux/debugfs.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/bootmem.h> +#include <linux/stacktrace.h> +#include <linux/page_owner.h> +#include "internal.h" + +static bool page_owner_disabled = true; +bool page_owner_inited __read_mostly; + +static int early_page_owner_param(char *buf) +{ + if (!buf) + return -EINVAL; + + if (strcmp(buf, "on") == 0) + page_owner_disabled = false; + + return 0; +} +early_param("page_owner", early_page_owner_param); + +static bool need_page_owner(void) +{ + if (page_owner_disabled) + return false; + + return true; +} + +static void init_page_owner(void) +{ + if (page_owner_disabled) + return; + + page_owner_inited = true; +} + +struct page_ext_operations page_owner_ops = { + .need = need_page_owner, + .init = init_page_owner, +}; + +void __reset_page_owner(struct page *page, unsigned int order) +{ + int i; + struct page_ext *page_ext; + + for (i = 0; i < (1 << order); i++) { + page_ext = lookup_page_ext(page + i); + __clear_bit(PAGE_EXT_OWNER, &page_ext->flags); + } +} + +void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask) +{ + struct page_ext *page_ext; + struct stack_trace *trace; + + page_ext = lookup_page_ext(page); + + trace = &page_ext->trace; + trace->nr_entries = 0; + trace->max_entries = ARRAY_SIZE(page_ext->trace_entries); + trace->entries = &page_ext->trace_entries[0]; + trace->skip = 3; + save_stack_trace(&page_ext->trace); + + page_ext->order = order; + page_ext->gfp_mask = gfp_mask; + + __set_bit(PAGE_EXT_OWNER, &page_ext->flags); +} + +static ssize_t +print_page_owner(char __user *buf, size_t count, unsigned long pfn, + struct page *page, struct page_ext *page_ext) +{ + int ret; + int pageblock_mt, page_mt; + char *kbuf; + + kbuf = kmalloc(count, GFP_KERNEL); + if (!kbuf) + return -ENOMEM; + + ret = snprintf(kbuf, count, + "Page allocated via order %u, mask 0x%x\n", + page_ext->order, page_ext->gfp_mask); + + if (ret >= count) + goto err; + + /* Print information relevant to grouping pages by mobility */ + pageblock_mt = get_pfnblock_migratetype(page, pfn); + page_mt = gfpflags_to_migratetype(page_ext->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, + pageblock_mt, + pageblock_mt != page_mt ? "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) + goto err; + + ret += snprint_stack_trace(kbuf + ret, count - ret, + &page_ext->trace, 0); + if (ret >= count) + goto err; + + ret += snprintf(kbuf + ret, count - ret, "\n"); + if (ret >= count) + goto err; + + if (copy_to_user(buf, kbuf, ret)) + ret = -EFAULT; + + kfree(kbuf); + return ret; + +err: + kfree(kbuf); + return -ENOMEM; +} + +static ssize_t +read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) +{ + unsigned long pfn; + struct page *page; + struct page_ext *page_ext; + + if (!page_owner_inited) + return -EINVAL; + + 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++; + + drain_all_pages(NULL); + + /* 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); + if (PageBuddy(page)) { + unsigned long freepage_order = page_order_unsafe(page); + + if (freepage_order < MAX_ORDER) + pfn += (1UL << freepage_order) - 1; + continue; + } + + page_ext = lookup_page_ext(page); + + /* + * Pages allocated before initialization of page_owner are + * non-buddy and have no page_owner info. + */ + if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags)) + continue; + + /* Record the next PFN to read in the file offset */ + *ppos = (pfn - min_low_pfn) + 1; + + return print_page_owner(buf, count, pfn, page, page_ext); + } + + return 0; +} + +static const struct file_operations proc_page_owner_operations = { + .read = read_page_owner, +}; + +static int __init pageowner_init(void) +{ + struct dentry *dentry; + + if (!page_owner_inited) { + pr_info("page_owner is disabled\n"); + return 0; + } + + dentry = debugfs_create_file("page_owner", S_IRUSR, NULL, + NULL, &proc_page_owner_operations); + if (IS_ERR(dentry)) + return PTR_ERR(dentry); + + return 0; +} +module_init(pageowner_init) |