From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rick Edgecombe Subject: [PATCH 14/17] mm: Make hibernate handle unmapped pages Date: Wed, 16 Jan 2019 16:32:56 -0800 Message-Id: <20190117003259.23141-15-rick.p.edgecombe@intel.com> In-Reply-To: <20190117003259.23141-1-rick.p.edgecombe@intel.com> References: <20190117003259.23141-1-rick.p.edgecombe@intel.com> To: Andy Lutomirski , Ingo Molnar Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com, Thomas Gleixner , Borislav Petkov , Nadav Amit , Dave Hansen , Peter Zijlstra , linux_dti@icloud.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, akpm@linux-foundation.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, will.deacon@arm.com, ard.biesheuvel@linaro.org, kristen@linux.intel.com, deneen.t.dock@intel.com, Rick Edgecombe , "Rafael J. Wysocki" , Pavel Machek List-ID: For architectures with CONFIG_ARCH_HAS_SET_ALIAS, pages can be unmapped briefly on the directmap, even when CONFIG_DEBUG_PAGEALLOC is not configured. So this changes kernel_map_pages and kernel_page_present to be defined when CONFIG_ARCH_HAS_SET_ALIAS is defined as well. It also changes places (page_alloc.c) where those functions are assumed to only be implemented when CONFIG_DEBUG_PAGEALLOC is defined. So now when CONFIG_ARCH_HAS_SET_ALIAS=y, hibernate will handle not present page when saving. Previously this was already done when CONFIG_DEBUG_PAGEALLOC was configured. It does not appear to have a big hibernating performance impact. Before: [ 4.670938] PM: Wrote 171996 kbytes in 0.21 seconds (819.02 MB/s) After: [ 4.504714] PM: Wrote 178932 kbytes in 0.22 seconds (813.32 MB/s) Cc: Dave Hansen Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: "Rafael J. Wysocki" Cc: Pavel Machek Signed-off-by: Rick Edgecombe --- arch/x86/mm/pageattr.c | 4 ---- include/linux/mm.h | 18 ++++++------------ mm/page_alloc.c | 6 ++++-- 3 files changed, 10 insertions(+), 18 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 3a51915a1410..717bdc188aab 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -2257,7 +2257,6 @@ int set_alias_default_noflush(struct page *page) return __set_pages_p(page, 1); } -#ifdef CONFIG_DEBUG_PAGEALLOC void __kernel_map_pages(struct page *page, int numpages, int enable) { if (PageHighMem(page)) @@ -2302,11 +2301,8 @@ bool kernel_page_present(struct page *page) pte = lookup_address((unsigned long)page_address(page), &level); return (pte_val(*pte) & _PAGE_PRESENT); } - #endif /* CONFIG_HIBERNATION */ -#endif /* CONFIG_DEBUG_PAGEALLOC */ - int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, unsigned numpages, unsigned long page_flags) { diff --git a/include/linux/mm.h b/include/linux/mm.h index 80bb6408fe73..b362a280a919 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2642,37 +2642,31 @@ static inline void kernel_poison_pages(struct page *page, int numpages, int enable) { } #endif -#ifdef CONFIG_DEBUG_PAGEALLOC extern bool _debug_pagealloc_enabled; -extern void __kernel_map_pages(struct page *page, int numpages, int enable); static inline bool debug_pagealloc_enabled(void) { - return _debug_pagealloc_enabled; + return IS_ENABLED(CONFIG_DEBUG_PAGEALLOC) && _debug_pagealloc_enabled; } +#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_ARCH_HAS_SET_ALIAS) +extern void __kernel_map_pages(struct page *page, int numpages, int enable); + static inline void kernel_map_pages(struct page *page, int numpages, int enable) { - if (!debug_pagealloc_enabled()) - return; - __kernel_map_pages(page, numpages, enable); } #ifdef CONFIG_HIBERNATION extern bool kernel_page_present(struct page *page); #endif /* CONFIG_HIBERNATION */ -#else /* CONFIG_DEBUG_PAGEALLOC */ +#else /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_ALIAS */ static inline void kernel_map_pages(struct page *page, int numpages, int enable) {} #ifdef CONFIG_HIBERNATION static inline bool kernel_page_present(struct page *page) { return true; } #endif /* CONFIG_HIBERNATION */ -static inline bool debug_pagealloc_enabled(void) -{ - return false; -} -#endif /* CONFIG_DEBUG_PAGEALLOC */ +#endif /* CONFIG_DEBUG_PAGEALLOC || CONFIG_ARCH_HAS_SET_ALIAS */ #ifdef __HAVE_ARCH_GATE_AREA extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d295c9bc01a8..c10a0d484aa6 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1074,7 +1074,8 @@ static __always_inline bool free_pages_prepare(struct page *page, } arch_free_page(page, order); kernel_poison_pages(page, 1 << order, 0); - kernel_map_pages(page, 1 << order, 0); + if (debug_pagealloc_enabled()) + kernel_map_pages(page, 1 << order, 0); kasan_free_nondeferred_pages(page, order); return true; @@ -1944,7 +1945,8 @@ inline void post_alloc_hook(struct page *page, unsigned int order, set_page_refcounted(page); arch_alloc_page(page, order); - kernel_map_pages(page, 1 << order, 1); + if (debug_pagealloc_enabled()) + kernel_map_pages(page, 1 << order, 1); kernel_poison_pages(page, 1 << order, 1); kasan_alloc_pages(page, order); set_page_owner(page, order, gfp_flags); -- 2.17.1