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: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Pavel 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: Ingo Molnar <mingo@kernel.org>

1 files changed, 6 insertions, 12 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6b10c21630f5..083d7b4863ed 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -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);