[PATCH] hugetlb: move cma reservation to code setting up gigantic hstate

[Mike Kravetz]

Instead of calling hugetlb_cma_reserve() directly from arch specific
code, call from hugetlb_add_hstate when adding a gigantic hstate.
hugetlb_add_hstate is either called from arch specific huge page setup,
or as the result of hugetlb command line processing.  In either case,
this is late enough in the init process that all numa memory information
should be initialized.  And, it is early enough to still use early
memory allocator.

Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
 arch/arm64/mm/init.c    | 10 ----------
 arch/x86/kernel/setup.c |  9 ---------
 include/linux/hugetlb.h | 12 ------------
 mm/hugetlb.c            | 32 ++++++++++++++++++++++++++++----
 4 files changed, 28 insertions(+), 35 deletions(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 79806732f4b4..ff0ff584dde9 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -427,16 +427,6 @@ void __init bootmem_init(void)
 	sparse_init();
 	zone_sizes_init(min, max);
 
-	/*
-	 * must be done after zone_sizes_init() which calls free_area_init()
-	 * that calls node_set_state() to initialize node_states[N_MEMORY]
-	 * because hugetlb_cma_reserve() will scan over nodes with N_MEMORY
-	 * state
-	 */
-#ifdef CONFIG_ARM64_4K_PAGES
-	hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
-#endif
-
 	memblock_dump_all();
 }
 
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index a1a9712090ae..111c8467fafa 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1177,15 +1177,6 @@ void __init setup_arch(char **cmdline_p)
 
 	x86_init.paging.pagetable_init();
 
-	/*
-	 * must be done after zone_sizes_init() which calls free_area_init()
-	 * that calls node_set_state() to initialize node_states[N_MEMORY]
-	 * because hugetlb_cma_reserve() will scan over nodes with N_MEMORY
-	 * state
-	 */
-	if (boot_cpu_has(X86_FEATURE_GBPAGES))
-		hugetlb_cma_reserve(PUD_SHIFT - PAGE_SHIFT);
-
 	kasan_init();
 
 	/*
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 6b9508dc31b4..5fadba1febcc 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -933,16 +933,4 @@ static inline spinlock_t *huge_pte_lock(struct hstate *h,
 	return ptl;
 }
 
-#if defined(CONFIG_HUGETLB_PAGE) && defined(CONFIG_CMA)
-extern void __init hugetlb_cma_reserve(int order);
-extern void __init hugetlb_cma_check(void);
-#else
-static inline __init void hugetlb_cma_reserve(int order)
-{
-}
-static inline __init void hugetlb_cma_check(void)
-{
-}
-#endif
-
 #endif /* _LINUX_HUGETLB_H */
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index f24acb3af741..2ca68c5620b7 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -76,8 +76,10 @@ DEFINE_SPINLOCK(hugetlb_lock);
 static int num_fault_mutexes;
 struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
 
-/* Forward declaration */
+/* Forward declarations */
 static int hugetlb_acct_memory(struct hstate *h, long delta);
+static void __init hugetlb_cma_reserve(int order);
+static void __init hugetlb_cma_check(void);
 
 static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
 {
@@ -3273,6 +3275,13 @@ void __init hugetlb_add_hstate(unsigned int order)
 	snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
 					huge_page_size(h)/1024);
 
+	/*
+	 * If user wants CMA for gigantic pages, reserve it now as we
+	 * set up the gigantic page hstate.
+	 */
+	if (hstate_is_gigantic(h) && hugetlb_cma_size)
+		hugetlb_cma_reserve(order);
+
 	parsed_hstate = h;
 }
 
@@ -5627,12 +5636,16 @@ void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
 #ifdef CONFIG_CMA
 static bool cma_reserve_called __initdata;
 
+/*
+ * early_param, as hugetlb_cma_size must be processed before any call to
+ * hugetlb_add_hstate by arch specific code or regular hugetlb command
+ * line processing.
+ */
 static int __init cmdline_parse_hugetlb_cma(char *p)
 {
 	hugetlb_cma_size = memparse(p, &p);
 	return 0;
 }
-
 early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
 
 /*
@@ -5642,11 +5655,13 @@ early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
  * hugetlb_cma_reserve() scans over N_MEMORY nodemask and hence expects the platforms
  * to have initialized N_MEMORY state.
  */
-void __init hugetlb_cma_reserve(int order)
+static void __init hugetlb_cma_reserve(int order)
 {
 	unsigned long size, reserved, per_node;
 	int nid;
 
+	if (cma_reserve_called)
+		return;
 	cma_reserve_called = true;
 
 	if (!hugetlb_cma_size)
@@ -5693,12 +5708,21 @@ void __init hugetlb_cma_reserve(int order)
 	}
 }
 
-void __init hugetlb_cma_check(void)
+static void __init hugetlb_cma_check(void)
 {
 	if (!hugetlb_cma_size || cma_reserve_called)
 		return;
 
 	pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
 }
+#else
+
+static void __init hugetlb_cma_reserve(int order)
+{
+}
+
+static void __init hugetlb_cma_check(void)
+{
+}
 
 #endif /* CONFIG_CMA */
-- 
2.25.4