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mm/hibernation: Make hibernation handle unmapped pages

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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>
This commit is contained in:
Rick Edgecombe
2019-04-25 17:11:35 -07:00
committed by Ingo Molnar
parent d253ca0c38
commit d633269286
4 changed files with 14 additions and 20 deletions
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5
kernel/power/snapshot.c
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@@ -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)
{