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#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)
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