1 files changed, 311 insertions, 0 deletions

diff --git a/mm/page_owner.c b/mm/page_owner.c
new file mode 100644
index 000000000000..9ab4a9b5bc09
--- /dev/null
+++ b/mm/page_owner.c
@@ -0,0 +1,311 @@
+#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 void init_early_allocated_pages(void);
+
+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;
+        init_early_allocated_pages();
+}
+
+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);
+
+                /*
+                 * Some pages could be missed by concurrent allocation or free,
+                 * because we don't hold the zone lock.
+                 */
+                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 void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
+{
+        struct page *page;
+        struct page_ext *page_ext;
+        unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
+        unsigned long end_pfn = pfn + zone->spanned_pages;
+        unsigned long count = 0;
+
+        /* Scan block by block. First and last block may be incomplete */
+        pfn = zone->zone_start_pfn;
+
+        /*
+         * 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; ) {
+                if (!pfn_valid(pfn)) {
+                        pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
+                        continue;
+                }
+
+                block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
+                block_end_pfn = min(block_end_pfn, end_pfn);
+
+                page = pfn_to_page(pfn);
+
+                for (; pfn < block_end_pfn; pfn++) {
+                        if (!pfn_valid_within(pfn))
+                                continue;
+
+                        page = pfn_to_page(pfn);
+
+                        /*
+                         * We are safe to check buddy flag and order, because
+                         * this is init stage and only single thread runs.
+                         */
+                        if (PageBuddy(page)) {
+                                pfn += (1UL << page_order(page)) - 1;
+                                continue;
+                        }
+
+                        if (PageReserved(page))
+                                continue;
+
+                        page_ext = lookup_page_ext(page);
+
+                        /* Maybe overraping zone */
+                        if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
+                                continue;
+
+                        /* Found early allocated page */
+                        set_page_owner(page, 0, 0);
+                        count++;
+                }
+        }
+
+        pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
+                pgdat->node_id, zone->name, count);
+}
+
+static void init_zones_in_node(pg_data_t *pgdat)
+{
+        struct zone *zone;
+        struct zone *node_zones = pgdat->node_zones;
+        unsigned long flags;
+
+        for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
+                if (!populated_zone(zone))
+                        continue;
+
+                spin_lock_irqsave(&zone->lock, flags);
+                init_pages_in_zone(pgdat, zone);
+                spin_unlock_irqrestore(&zone->lock, flags);
+        }
+}
+
+static void init_early_allocated_pages(void)
+{
+        pg_data_t *pgdat;
+
+        drain_all_pages(NULL);
+        for_each_online_pgdat(pgdat)
+                init_zones_in_node(pgdat);
+}
+
+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)