mm: add __dump_folio()
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: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle)
Andrew Morton
parent
7da8988c7c
commit
fae7d834c4
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@ -2066,6 +2066,13 @@ static inline long folio_nr_pages(struct folio *folio)
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#endif
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}
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/* Only hugetlbfs can allocate folios larger than MAX_ORDER */
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#ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
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#define MAX_FOLIO_NR_PAGES (1UL << PUD_ORDER)
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#else
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#define MAX_FOLIO_NR_PAGES MAX_ORDER_NR_PAGES
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#endif
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/*
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* compound_nr() returns the number of pages in this potentially compound
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* page. compound_nr() can be called on a tail page, and is defined to
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@ -76,9 +76,12 @@ extern const char * const migratetype_names[MIGRATE_TYPES];
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#ifdef CONFIG_CMA
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# define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
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# define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
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# define is_migrate_cma_folio(folio, pfn) (MIGRATE_CMA == \
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get_pfnblock_flags_mask(&folio->page, pfn, MIGRATETYPE_MASK))
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#else
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# define is_migrate_cma(migratetype) false
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# define is_migrate_cma_page(_page) false
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# define is_migrate_cma_folio(folio, pfn) false
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#endif
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static inline bool is_migrate_movable(int mt)
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128
mm/debug.c
128
mm/debug.c
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@ -51,84 +51,102 @@ const struct trace_print_flags vmaflag_names[] = {
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{0, NULL}
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};
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static void __dump_page(struct page *page)
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static void __dump_folio(struct folio *folio, struct page *page,
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unsigned long pfn, unsigned long idx)
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{
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struct folio *folio = page_folio(page);
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struct page *head = &folio->page;
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struct address_space *mapping;
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bool compound = PageCompound(page);
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/*
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* Accessing the pageblock without the zone lock. It could change to
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* "isolate" again in the meantime, but since we are just dumping the
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* state for debugging, it should be fine to accept a bit of
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* inaccuracy here due to racing.
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*/
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bool page_cma = is_migrate_cma_page(page);
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int mapcount;
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struct address_space *mapping = folio_mapping(folio);
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int mapcount = 0;
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char *type = "";
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if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
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/*
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* Corrupt page, so we cannot call page_mapping. Instead, do a
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* safe subset of the steps that page_mapping() does. Caution:
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* this will be misleading for tail pages, PageSwapCache pages,
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* and potentially other situations. (See the page_mapping()
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* implementation for what's missing here.)
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*/
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unsigned long tmp = (unsigned long)page->mapping;
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if (tmp & PAGE_MAPPING_ANON)
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mapping = NULL;
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else
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mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);
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head = page;
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folio = (struct folio *)page;
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compound = false;
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} else {
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mapping = page_mapping(page);
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/*
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* page->_mapcount space in struct page is used by slab pages to
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* encode own info, and we must avoid calling page_folio() again.
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*/
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if (!folio_test_slab(folio)) {
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mapcount = atomic_read(&page->_mapcount) + 1;
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if (folio_test_large(folio))
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mapcount += folio_entire_mapcount(folio);
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}
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/*
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* Avoid VM_BUG_ON() in page_mapcount().
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* page->_mapcount space in struct page is used by sl[aou]b pages to
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* encode own info.
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*/
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mapcount = PageSlab(head) ? 0 : page_mapcount(page);
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pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
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page, page_ref_count(head), mapcount, mapping,
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page_to_pgoff(page), page_to_pfn(page));
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if (compound) {
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pr_warn("head:%p order:%u entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",
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head, compound_order(head),
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pr_warn("page: refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
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folio_ref_count(folio), mapcount, mapping,
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folio->index + idx, pfn);
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if (folio_test_large(folio)) {
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pr_warn("head: order:%u entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",
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folio_order(folio),
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folio_entire_mapcount(folio),
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folio_nr_pages_mapped(folio),
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atomic_read(&folio->_pincount));
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}
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#ifdef CONFIG_MEMCG
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if (head->memcg_data)
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pr_warn("memcg:%lx\n", head->memcg_data);
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if (folio->memcg_data)
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pr_warn("memcg:%lx\n", folio->memcg_data);
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#endif
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if (PageKsm(page))
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if (folio_test_ksm(folio))
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type = "ksm ";
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else if (PageAnon(page))
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else if (folio_test_anon(folio))
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type = "anon ";
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else if (mapping)
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dump_mapping(mapping);
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BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
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pr_warn("%sflags: %pGp%s\n", type, &head->flags,
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page_cma ? " CMA" : "");
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pr_warn("page_type: %pGt\n", &head->page_type);
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/*
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* Accessing the pageblock without the zone lock. It could change to
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* "isolate" again in the meantime, but since we are just dumping the
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* state for debugging, it should be fine to accept a bit of
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* inaccuracy here due to racing.
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*/
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pr_warn("%sflags: %pGp%s\n", type, &folio->flags,
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is_migrate_cma_folio(folio, pfn) ? " CMA" : "");
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pr_warn("page_type: %pGt\n", &folio->page.page_type);
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print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
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sizeof(unsigned long), page,
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sizeof(struct page), false);
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if (head != page)
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if (folio_test_large(folio))
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print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
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sizeof(unsigned long), head,
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sizeof(struct page), false);
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sizeof(unsigned long), folio,
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2 * sizeof(struct page), false);
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}
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static void __dump_page(const struct page *page)
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{
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struct folio *foliop, folio;
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struct page precise;
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unsigned long pfn = page_to_pfn(page);
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unsigned long idx, nr_pages = 1;
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int loops = 5;
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again:
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memcpy(&precise, page, sizeof(*page));
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foliop = page_folio(&precise);
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if (foliop == (struct folio *)&precise) {
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idx = 0;
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if (!folio_test_large(foliop))
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goto dump;
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foliop = (struct folio *)page;
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} else {
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idx = folio_page_idx(foliop, page);
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}
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if (idx < MAX_FOLIO_NR_PAGES) {
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memcpy(&folio, foliop, 2 * sizeof(struct page));
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nr_pages = folio_nr_pages(&folio);
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foliop = &folio;
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}
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if (idx > nr_pages) {
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if (loops-- > 0)
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goto again;
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pr_warn("page does not match folio\n");
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precise.compound_head &= ~1UL;
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foliop = (struct folio *)&precise;
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idx = 0;
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}
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dump:
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__dump_folio(foliop, &precise, pfn, idx);
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}
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void dump_page(struct page *page, const char *reason)
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