Commit d6332692 authored by Rick Edgecombe's avatar Rick Edgecombe Committed by Ingo Molnar
Browse files

mm/hibernation: Make hibernation handle unmapped pages 



Make hibernate handle unmapped pages on the direct map when
CONFIG_ARCH_HAS_SET_ALIAS=y is set. These functions allow for setting pages
to invalid configurations, so now hibernate should check if the pages have
valid mappings and handle if they are unmapped when doing a hibernate
save operation.

Previously this checking was already done when CONFIG_DEBUG_PAGEALLOC=y
was configured. It does not appear to have a big hibernating performance
impact. The speed of the saving operation before this change was measured
as 819.02 MB/s, and after was measured at 813.32 MB/s.

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)

Signed-off-by: default avatarRick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarPavel Machek <pavel@ucw.cz>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-16-namit@vmware.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent d253ca0c

arch/x86/mm/pageattr.c

+0 −4
Original line number Diff line number Diff line
@@ -2257,7 +2257,6 @@ int set_direct_map_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)

{

include/linux/mm.h

+6 −12
Original line number Diff line number Diff line
@@ -2610,37 +2610,31 @@ 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_DIRECT_MAP)

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_DIRECT_MAP */

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_DIRECT_MAP */



#ifdef __HAVE_ARCH_GATE_AREA

extern struct vm_area_struct *get_gate_vma(struct mm_struct *mm);

kernel/power/snapshot.c

+3 −2
Original line number Diff line number Diff line
@@ -1342,8 +1342,9 @@ static inline void do_copy_page(long *dst, long *src) 
 * safe_copy_page - Copy a page in a safe way.

 *

 * Check if the page we are going to copy is marked as present in the kernel

 * page tables (this always is the case if CONFIG_DEBUG_PAGEALLOC is not set

 * and in that case kernel_page_present() always returns 'true').

 * page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or

 * CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present()

 * always returns 'true'.

 */

static void safe_copy_page(void *dst, struct page *s_page)

{

mm/page_alloc.c

+5 −2
Original line number Diff line number Diff line
@@ -1144,7 +1144,9 @@ static __always_inline bool free_pages_prepare(struct page *page, 
	}

	arch_free_page(page, order);

	kernel_poison_pages(page, 1 << order, 0);

	if (debug_pagealloc_enabled())

		kernel_map_pages(page, 1 << order, 0);



	kasan_free_nondeferred_pages(page, order);



	return true;
@@ -2014,6 +2016,7 @@ inline void post_alloc_hook(struct page *page, unsigned int order, 
	set_page_refcounted(page);



	arch_alloc_page(page, order);

	if (debug_pagealloc_enabled())

		kernel_map_pages(page, 1 << order, 1);

	kasan_alloc_pages(page, order);

	kernel_poison_pages(page, 1 << order, 1);

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