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![Joonsoo Kim](/assets/img/avatar_default.png)
Currently, we set wrong gfp_mask to page_owner info in case of isolated freepage by compaction and split page. It causes incorrect mixed pageblock report that we can get from '/proc/pagetypeinfo'. This metric is really useful to measure fragmentation effect so should be accurate. This patch fixes it by setting correct information. Without this patch, after kernel build workload is finished, number of mixed pageblock is 112 among roughly 210 movable pageblocks. But, with this fix, output shows that mixed pageblock is just 57. Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
320 lines
7.1 KiB
C
320 lines
7.1 KiB
C
#include <linux/debugfs.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/bootmem.h>
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#include <linux/stacktrace.h>
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#include <linux/page_owner.h>
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#include "internal.h"
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static bool page_owner_disabled = true;
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bool page_owner_inited __read_mostly;
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static void init_early_allocated_pages(void);
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static int early_page_owner_param(char *buf)
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{
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if (!buf)
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return -EINVAL;
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if (strcmp(buf, "on") == 0)
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page_owner_disabled = false;
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return 0;
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}
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early_param("page_owner", early_page_owner_param);
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static bool need_page_owner(void)
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{
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if (page_owner_disabled)
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return false;
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return true;
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}
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static void init_page_owner(void)
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{
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if (page_owner_disabled)
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return;
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page_owner_inited = true;
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init_early_allocated_pages();
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}
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struct page_ext_operations page_owner_ops = {
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.need = need_page_owner,
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.init = init_page_owner,
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};
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void __reset_page_owner(struct page *page, unsigned int order)
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{
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int i;
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struct page_ext *page_ext;
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for (i = 0; i < (1 << order); i++) {
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page_ext = lookup_page_ext(page + i);
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__clear_bit(PAGE_EXT_OWNER, &page_ext->flags);
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}
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}
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void __set_page_owner(struct page *page, unsigned int order, gfp_t gfp_mask)
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{
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struct page_ext *page_ext = lookup_page_ext(page);
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struct stack_trace trace = {
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.nr_entries = 0,
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.max_entries = ARRAY_SIZE(page_ext->trace_entries),
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.entries = &page_ext->trace_entries[0],
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.skip = 3,
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};
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save_stack_trace(&trace);
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page_ext->order = order;
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page_ext->gfp_mask = gfp_mask;
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page_ext->nr_entries = trace.nr_entries;
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__set_bit(PAGE_EXT_OWNER, &page_ext->flags);
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}
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gfp_t __get_page_owner_gfp(struct page *page)
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{
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struct page_ext *page_ext = lookup_page_ext(page);
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return page_ext->gfp_mask;
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}
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static ssize_t
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print_page_owner(char __user *buf, size_t count, unsigned long pfn,
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struct page *page, struct page_ext *page_ext)
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{
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int ret;
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int pageblock_mt, page_mt;
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char *kbuf;
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struct stack_trace trace = {
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.nr_entries = page_ext->nr_entries,
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.entries = &page_ext->trace_entries[0],
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};
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kbuf = kmalloc(count, GFP_KERNEL);
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if (!kbuf)
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return -ENOMEM;
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ret = snprintf(kbuf, count,
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"Page allocated via order %u, mask 0x%x\n",
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page_ext->order, page_ext->gfp_mask);
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if (ret >= count)
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goto err;
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/* Print information relevant to grouping pages by mobility */
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pageblock_mt = get_pfnblock_migratetype(page, pfn);
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page_mt = gfpflags_to_migratetype(page_ext->gfp_mask);
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ret += snprintf(kbuf + ret, count - ret,
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"PFN %lu Block %lu type %d %s Flags %s%s%s%s%s%s%s%s%s%s%s%s\n",
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pfn,
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pfn >> pageblock_order,
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pageblock_mt,
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pageblock_mt != page_mt ? "Fallback" : " ",
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PageLocked(page) ? "K" : " ",
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PageError(page) ? "E" : " ",
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PageReferenced(page) ? "R" : " ",
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PageUptodate(page) ? "U" : " ",
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PageDirty(page) ? "D" : " ",
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PageLRU(page) ? "L" : " ",
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PageActive(page) ? "A" : " ",
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PageSlab(page) ? "S" : " ",
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PageWriteback(page) ? "W" : " ",
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PageCompound(page) ? "C" : " ",
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PageSwapCache(page) ? "B" : " ",
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PageMappedToDisk(page) ? "M" : " ");
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if (ret >= count)
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goto err;
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ret += snprint_stack_trace(kbuf + ret, count - ret, &trace, 0);
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if (ret >= count)
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goto err;
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ret += snprintf(kbuf + ret, count - ret, "\n");
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if (ret >= count)
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goto err;
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if (copy_to_user(buf, kbuf, ret))
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ret = -EFAULT;
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kfree(kbuf);
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return ret;
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err:
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kfree(kbuf);
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return -ENOMEM;
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}
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static ssize_t
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read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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{
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unsigned long pfn;
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struct page *page;
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struct page_ext *page_ext;
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if (!page_owner_inited)
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return -EINVAL;
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page = NULL;
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pfn = min_low_pfn + *ppos;
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/* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */
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while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
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pfn++;
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drain_all_pages(NULL);
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/* Find an allocated page */
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for (; pfn < max_pfn; pfn++) {
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/*
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* If the new page is in a new MAX_ORDER_NR_PAGES area,
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* validate the area as existing, skip it if not
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*/
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if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
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pfn += MAX_ORDER_NR_PAGES - 1;
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continue;
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}
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/* Check for holes within a MAX_ORDER area */
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if (!pfn_valid_within(pfn))
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continue;
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page = pfn_to_page(pfn);
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if (PageBuddy(page)) {
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unsigned long freepage_order = page_order_unsafe(page);
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if (freepage_order < MAX_ORDER)
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pfn += (1UL << freepage_order) - 1;
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continue;
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}
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page_ext = lookup_page_ext(page);
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/*
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* Some pages could be missed by concurrent allocation or free,
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* because we don't hold the zone lock.
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*/
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if (!test_bit(PAGE_EXT_OWNER, &page_ext->flags))
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continue;
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/* Record the next PFN to read in the file offset */
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*ppos = (pfn - min_low_pfn) + 1;
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return print_page_owner(buf, count, pfn, page, page_ext);
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}
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return 0;
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}
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static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
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{
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struct page *page;
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struct page_ext *page_ext;
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unsigned long pfn = zone->zone_start_pfn, block_end_pfn;
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unsigned long end_pfn = pfn + zone->spanned_pages;
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unsigned long count = 0;
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/* Scan block by block. First and last block may be incomplete */
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pfn = zone->zone_start_pfn;
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/*
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* Walk the zone in pageblock_nr_pages steps. If a page block spans
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* a zone boundary, it will be double counted between zones. This does
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* not matter as the mixed block count will still be correct
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*/
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for (; pfn < end_pfn; ) {
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if (!pfn_valid(pfn)) {
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pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
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continue;
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}
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block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
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block_end_pfn = min(block_end_pfn, end_pfn);
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page = pfn_to_page(pfn);
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for (; pfn < block_end_pfn; pfn++) {
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if (!pfn_valid_within(pfn))
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continue;
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page = pfn_to_page(pfn);
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/*
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* We are safe to check buddy flag and order, because
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* this is init stage and only single thread runs.
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*/
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if (PageBuddy(page)) {
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pfn += (1UL << page_order(page)) - 1;
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continue;
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}
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if (PageReserved(page))
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continue;
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page_ext = lookup_page_ext(page);
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/* Maybe overraping zone */
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if (test_bit(PAGE_EXT_OWNER, &page_ext->flags))
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continue;
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/* Found early allocated page */
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set_page_owner(page, 0, 0);
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count++;
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}
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}
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pr_info("Node %d, zone %8s: page owner found early allocated %lu pages\n",
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pgdat->node_id, zone->name, count);
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}
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static void init_zones_in_node(pg_data_t *pgdat)
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{
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struct zone *zone;
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struct zone *node_zones = pgdat->node_zones;
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unsigned long flags;
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for (zone = node_zones; zone - node_zones < MAX_NR_ZONES; ++zone) {
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if (!populated_zone(zone))
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continue;
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spin_lock_irqsave(&zone->lock, flags);
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init_pages_in_zone(pgdat, zone);
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spin_unlock_irqrestore(&zone->lock, flags);
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}
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}
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static void init_early_allocated_pages(void)
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{
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pg_data_t *pgdat;
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drain_all_pages(NULL);
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for_each_online_pgdat(pgdat)
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init_zones_in_node(pgdat);
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}
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static const struct file_operations proc_page_owner_operations = {
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.read = read_page_owner,
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};
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static int __init pageowner_init(void)
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{
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struct dentry *dentry;
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if (!page_owner_inited) {
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pr_info("page_owner is disabled\n");
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return 0;
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}
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dentry = debugfs_create_file("page_owner", S_IRUSR, NULL,
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NULL, &proc_page_owner_operations);
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if (IS_ERR(dentry))
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return PTR_ERR(dentry);
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return 0;
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}
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late_initcall(pageowner_init)
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