Commit 27189c75 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Jinjiang Tu
Browse files

mm: add __dump_folio() 

mainline inclusion
from mainline-v6.9-rc1
commit fae7d834c43ccdb9fcecaf4d0f33145d884b3e5c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IACHGW

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=fae7d834c43ccdb9fcecaf4d0f33145d884b3e5c

-------------------------------------------

Turn __dump_page() into a wrapper around __dump_folio().  Snapshot the
page & folio into a stack variable so we don't hit BUG_ON() if an
allocation is freed under us and what was a folio pointer becomes a
pointer to a tail page.

[willy@infradead.org: fix build issue]
  Link: https://lkml.kernel.org/r/ZeAKCyTn_xS3O9cE@casper.infradead.org
[willy@infradead.org: fix __dump_folio]
  Link: https://lkml.kernel.org/r/ZeJJegP8zM7S9GTy@casper.infradead.org
[willy@infradead.org: fix pointer confusion]
  Link: https://lkml.kernel.org/r/ZeYa00ixxC4k1ot-@casper.infradead.org
[akpm@linux-foundation.org: s/printk/pr_warn/]
Link: https://lkml.kernel.org/r/20240227192337.757313-5-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarJinjiang Tu <tujinjiang@huawei.com>
parent 26ffc748

include/linux/mm.h

+7 −0
Original line number Diff line number Diff line
@@ -2084,6 +2084,13 @@ static inline long folio_nr_pages(struct folio *folio) 
#endif

}



/* Only hugetlbfs can allocate folios larger than MAX_ORDER */

#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE

#define MAX_FOLIO_NR_PAGES	(1UL << PUD_ORDER)

#else

#define MAX_FOLIO_NR_PAGES	MAX_ORDER_NR_PAGES

#endif



/*

 * compound_nr() returns the number of pages in this potentially compound

 * page.  compound_nr() can be called on a tail page, and is defined to

include/linux/mmzone.h

+3 −0
Original line number Diff line number Diff line
@@ -75,9 +75,12 @@ extern const char * const migratetype_names[MIGRATE_TYPES]; 
#ifdef CONFIG_CMA

#  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)

#  define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)

#  define is_migrate_cma_folio(folio, pfn)	(MIGRATE_CMA ==		\

	get_pfnblock_flags_mask(&folio->page, pfn, MIGRATETYPE_MASK))

#else

#  define is_migrate_cma(migratetype) false

#  define is_migrate_cma_page(_page) false

#  define is_migrate_cma_folio(folio, pfn) false

#endif



static inline bool is_migrate_movable(int mt)

mm/debug.c

+73 −55
Original line number Diff line number Diff line
@@ -51,84 +51,102 @@ const struct trace_print_flags vmaflag_names[] = { 
	{0, NULL}

};



static void __dump_page(struct page *page)

static void __dump_folio(struct folio *folio, struct page *page,

		unsigned long pfn, unsigned long idx)

{

	struct folio *folio = page_folio(page);

	struct page *head = &folio->page;

	struct address_space *mapping;

	bool compound = PageCompound(page);

	/*

	 * Accessing the pageblock without the zone lock. It could change to

	 * "isolate" again in the meantime, but since we are just dumping the

	 * state for debugging, it should be fine to accept a bit of

	 * inaccuracy here due to racing.

	 */

	bool page_cma = is_migrate_cma_page(page);

	int mapcount;

	struct address_space *mapping = folio_mapping(folio);

	int mapcount = 0;

	char *type = "";



	if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {

	/*

		 * Corrupt page, so we cannot call page_mapping. Instead, do a

		 * safe subset of the steps that page_mapping() does. Caution:

		 * this will be misleading for tail pages, PageSwapCache pages,

		 * and potentially other situations. (See the page_mapping()

		 * implementation for what's missing here.)

	 * page->_mapcount space in struct page is used by slab pages to

	 * encode own info, and we must avoid calling page_folio() again.

	 */

		unsigned long tmp = (unsigned long)page->mapping;



		if (tmp & PAGE_MAPPING_ANON)

			mapping = NULL;

		else

			mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);

		head = page;

		folio = (struct folio *)page;

		compound = false;

	} else {

		mapping = page_mapping(page);

	if (!folio_test_slab(folio)) {

		mapcount = atomic_read(&page->_mapcount) + 1;

		if (folio_test_large(folio))

			mapcount += folio_entire_mapcount(folio);

	}



	/*

	 * Avoid VM_BUG_ON() in page_mapcount().

	 * page->_mapcount space in struct page is used by sl[aou]b pages to

	 * encode own info.

	 */

	mapcount = PageSlab(head) ? 0 : page_mapcount(page);



	pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",

			page, page_ref_count(head), mapcount, mapping,

			page_to_pgoff(page), page_to_pfn(page));

	if (compound) {

		pr_warn("head:%p order:%u entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",

				head, compound_order(head),

	pr_warn("page: refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",

			folio_ref_count(folio), mapcount, mapping,

			folio->index + idx, pfn);

	if (folio_test_large(folio)) {

		pr_warn("head: order:%u entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",

				folio_order(folio),

				folio_entire_mapcount(folio),

				folio_nr_pages_mapped(folio),

				atomic_read(&folio->_pincount));

	}



#ifdef CONFIG_MEMCG

	if (head->memcg_data)

		pr_warn("memcg:%lx\n", head->memcg_data);

	if (folio->memcg_data)

		pr_warn("memcg:%lx\n", folio->memcg_data);

#endif

	if (PageKsm(page))

	if (folio_test_ksm(folio))

		type = "ksm ";

	else if (PageAnon(page))

	else if (folio_test_anon(folio))

		type = "anon ";

	else if (mapping)

		dump_mapping(mapping);

	BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);



	pr_warn("%sflags: %pGp%s\n", type, &head->flags,

		page_cma ? " CMA" : "");

	pr_warn("page_type: %pGt\n", &head->page_type);

	/*

	 * Accessing the pageblock without the zone lock. It could change to

	 * "isolate" again in the meantime, but since we are just dumping the

	 * state for debugging, it should be fine to accept a bit of

	 * inaccuracy here due to racing.

	 */

	pr_warn("%sflags: %pGp%s\n", type, &folio->flags,

		is_migrate_cma_folio(folio, pfn) ? " CMA" : "");

	pr_warn("page_type: %pGt\n", &folio->page.page_type);



	print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,

			sizeof(unsigned long), page,

			sizeof(struct page), false);

	if (head != page)

	if (folio_test_large(folio))

		print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,

			sizeof(unsigned long), head,

			sizeof(struct page), false);

			sizeof(unsigned long), folio,

			2 * sizeof(struct page), false);

}



static void __dump_page(const struct page *page)

{

	struct folio *foliop, folio;

	struct page precise;

	unsigned long pfn = page_to_pfn(page);

	unsigned long idx, nr_pages = 1;

	int loops = 5;



again:

	memcpy(&precise, page, sizeof(*page));

	foliop = page_folio(&precise);

	if (foliop == (struct folio *)&precise) {

		idx = 0;

		if (!folio_test_large(foliop))

			goto dump;

		foliop = (struct folio *)page;

	} else {

		idx = folio_page_idx(foliop, page);

	}



	if (idx < MAX_FOLIO_NR_PAGES) {

		memcpy(&folio, foliop, 2 * sizeof(struct page));

		nr_pages = folio_nr_pages(&folio);

		foliop = &folio;

	}



	if (idx > nr_pages) {

		if (loops-- > 0)

			goto again;

		pr_warn("page does not match folio\n");

		precise.compound_head &= ~1UL;

		foliop = (struct folio *)&precise;

		idx = 0;

	}



dump:

	__dump_folio(foliop, &precise, pfn, idx);

}



void dump_page(struct page *page, const char *reason)