From: Anshuman Khandual <anshuman.khandual@arm.com>
Date: Mon, 23 Aug 2021 23:59:37 +0000 (+1000)
Subject: mm/thp: make ALLOC_SPLIT_PTLOCKS dependent on USE_SPLIT_PTE_PTLOCKS
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=883146b11ef19d4466be13939c8605c614819cc8;p=users%2Fjedix%2Flinux-maple.git

mm/thp: make ALLOC_SPLIT_PTLOCKS dependent on USE_SPLIT_PTE_PTLOCKS

Split ptlocks need not be defined and allocated unless they are being
used.  ALLOC_SPLIT_PTLOCKS is inherently dependent on
USE_SPLIT_PTE_PTLOCKS.  This just makes it explicit and clear.  While here
drop the spinlock_t element from the struct page when
USE_SPLIT_PTE_PTLOCKS is not enabled.

Link: https://lkml.kernel.org/r/1621409586-5555-1-git-send-email-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 52bbd2b7cb46..f37abb2d222e 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -159,10 +159,12 @@ struct page {
 				struct mm_struct *pt_mm; /* x86 pgds only */
 				atomic_t pt_frag_refcount; /* powerpc */
 			};
+#if USE_SPLIT_PTE_PTLOCKS
 #if ALLOC_SPLIT_PTLOCKS
 			spinlock_t *ptl;
 #else
 			spinlock_t ptl;
+#endif
 #endif
 		};
 		struct {	/* ZONE_DEVICE pages */
diff --git a/include/linux/mm_types_task.h b/include/linux/mm_types_task.h
index c1bc6731125c..1b222f8039d1 100644
--- a/include/linux/mm_types_task.h
+++ b/include/linux/mm_types_task.h
@@ -22,7 +22,12 @@
 #define USE_SPLIT_PTE_PTLOCKS	(NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS)
 #define USE_SPLIT_PMD_PTLOCKS	(USE_SPLIT_PTE_PTLOCKS && \
 		IS_ENABLED(CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK))
+
+#if USE_SPLIT_PTE_PTLOCKS
 #define ALLOC_SPLIT_PTLOCKS	(SPINLOCK_SIZE > BITS_PER_LONG/8)
+#else
+#define ALLOC_SPLIT_PTLOCKS	0
+#endif
 
 /*
  * The per task VMA cache array:
diff --git a/mm/memory.c b/mm/memory.c
index 25fc46e87214..94a17a9a48ab 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5441,7 +5441,7 @@ long copy_huge_page_from_user(struct page *dst_page,
 }
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
 
-#if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS
+#if ALLOC_SPLIT_PTLOCKS
 
 static struct kmem_cache *page_ptl_cachep;