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-rw-r--r--mm/page_owner.c222
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)