Subject: [PATCH v1 7/9] arm64: kdump: No need to mark crashkernel pages manually PG_reserved

From: David Hildenbrand <[email-masked]>
Date: Fri, 14 Dec 2018 12:10:12 +0100

The crashkernel is reserved via memblock_reserve(). memblock_free_all()
will call free_low_memory_core_early(), which will go over all reserved
memblocks, marking the pages as PG_reserved.

So manually marking pages as PG_reserved is not necessary, they are
already in the desired state (otherwise they would have been handed over
to the buddy as free pages and bad things would happen).

Cc: Catalin Marinas <[email-masked]>
Cc: Will Deacon <[email-masked]>
Cc: James Morse <[email-masked]>
Cc: Bhupesh Sharma <[email-masked]>
Cc: David Hildenbrand <[email-masked]>
Cc: Mark Rutland <[email-masked]>
Cc: Dave Kleikamp <[email-masked]>
Cc: Andrew Morton <[email-masked]>
Cc: Mike Rapoport <[email-masked]>
Cc: Michal Hocko <[email-masked]>
Cc: Florian Fainelli <[email-masked]>
Cc: Stefan Agner <[email-masked]>
Cc: Laura Abbott <[email-masked]>
Cc: Greg Hackmann <[email-masked]>
Cc: Johannes Weiner <[email-masked]>
Cc: Kristina Martsenko <[email-masked]>
Cc: CHANDAN VN <[email-masked]>
Cc: AKASHI Takahiro <[email-masked]>
Cc: Logan Gunthorpe <[email-masked]>
Signed-off-by: David Hildenbrand <[email-masked]>
---
 arch/arm64/kernel/machine_kexec.c |  2 +-
 arch/arm64/mm/init.c              | 27 ---------------------------
 2 files changed, 1 insertion(+), 28 deletions(-)

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 6f0587b5e941..66b5d697d943 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -321,7 +321,7 @@ void crash_post_resume(void)
  * but does not hold any data of loaded kernel image.
  *
  * Note that all the pages in crash dump kernel memory have been initially
- * marked as Reserved in kexec_reserve_crashkres_pages().
+ * marked as Reserved as memory was allocated via memblock_reserve().
  *
  * In hibernation, the pages which are Reserved and yet "nosave" are excluded
  * from the hibernation iamge. crash_is_nosave() does thich check for crash
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index a8f2e4792ef9..9dcfa809b7ab 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -118,35 +118,10 @@ static void __init reserve_crashkernel(void)
 	crashk_res.start = crash_base;
 	crashk_res.end = crash_base + crash_size - 1;
 }
-
-static void __init kexec_reserve_crashkres_pages(void)
-{
-#ifdef CONFIG_HIBERNATION
-	phys_addr_t addr;
-	struct page *page;
-
-	if (!crashk_res.end)
-		return;
-
-	/*
-	 * To reduce the size of hibernation image, all the pages are
-	 * marked as Reserved initially.
-	 */
-	for (addr = crashk_res.start; addr < (crashk_res.end + 1);
-			addr += PAGE_SIZE) {
-		page = phys_to_page(addr);
-		SetPageReserved(page);
-	}
-#endif
-}
 #else
 static void __init reserve_crashkernel(void)
 {
 }
-
-static void __init kexec_reserve_crashkres_pages(void)
-{
-}
 #endif /* CONFIG_KEXEC_CORE */
 
 #ifdef CONFIG_CRASH_DUMP
@@ -586,8 +561,6 @@ void __init mem_init(void)
 	/* this will put all unused low memory onto the freelists */
 	memblock_free_all();
 
-	kexec_reserve_crashkres_pages();
-
 	mem_init_print_info(NULL);
 
 	/*
-- 
2.17.2