[PATCHv2 2/3] mm/memblock: Allocate boot time data structures from mirrored memory

[Tony Luck]

Try to allocate all boot time kernel data structures from mirrored
memory. If we run out of mirrored memory print warnings, but fall
back to using non-mirrored memory to make sure that we still boot.

Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
---

v1->v2:
	Better name for memblock_has_mirror() - now choose_memblock_flags()
	Print phys_addr_t with %pap instead of %lld
	Don't fall back by clearing flags. Use: flags &= ~MEMBLOCK_MIRROR;
	Keep to 80 columns

N.B just one checkpatch warning about initializing a static to 0:
+static bool system_has_some_mirror __initdata_memblock = false;
This fits with existing style in the file ... but zap the " = false" if you
like - I have no strong feelings about this.

 include/linux/memblock.h |  8 +++++
 mm/memblock.c            | 78 +++++++++++++++++++++++++++++++++++++++++-------
 mm/nobootmem.c           | 10 ++++++-
 3 files changed, 84 insertions(+), 12 deletions(-)

diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 7aeec0cb4c27..0215ffd63069 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -24,6 +24,7 @@
 enum {
 	MEMBLOCK_NONE		= 0x0,	/* No special request */
 	MEMBLOCK_HOTPLUG	= 0x1,	/* hotpluggable region */
+	MEMBLOCK_MIRROR		= 0x2,	/* mirrored region */
 };
 
 struct memblock_region {
@@ -78,6 +79,8 @@ int memblock_reserve(phys_addr_t base, phys_addr_t size);
 void memblock_trim_memory(phys_addr_t align);
 int memblock_mark_hotplug(phys_addr_t base, phys_addr_t size);
 int memblock_clear_hotplug(phys_addr_t base, phys_addr_t size);
+int memblock_mark_mirror(phys_addr_t base, phys_addr_t size);
+ulong choose_memblock_flags(void);
 
 /* Low level functions */
 int memblock_add_range(struct memblock_type *type,
@@ -160,6 +163,11 @@ static inline bool movable_node_is_enabled(void)
 }
 #endif
 
+static inline bool memblock_is_mirror(struct memblock_region *m)
+{
+	return m->flags & MEMBLOCK_MIRROR;
+}
+
 #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
 int memblock_search_pfn_nid(unsigned long pfn, unsigned long *start_pfn,
 			    unsigned long  *end_pfn);
diff --git a/mm/memblock.c b/mm/memblock.c
index b9ff2f4f0285..1b444c730846 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -54,10 +54,16 @@ int memblock_debug __initdata_memblock;
 #ifdef CONFIG_MOVABLE_NODE
 bool movable_node_enabled __initdata_memblock = false;
 #endif
+static bool system_has_some_mirror __initdata_memblock = false;
 static int memblock_can_resize __initdata_memblock;
 static int memblock_memory_in_slab __initdata_memblock = 0;
 static int memblock_reserved_in_slab __initdata_memblock = 0;
 
+ulong __init_memblock choose_memblock_flags(void)
+{
+	return system_has_some_mirror ? MEMBLOCK_MIRROR : MEMBLOCK_NONE;
+}
+
 /* inline so we don't get a warning when pr_debug is compiled out */
 static __init_memblock const char *
 memblock_type_name(struct memblock_type *type)
@@ -259,8 +265,21 @@ phys_addr_t __init_memblock memblock_find_in_range(phys_addr_t start,
 					phys_addr_t end, phys_addr_t size,
 					phys_addr_t align)
 {
-	return memblock_find_in_range_node(size, align, start, end,
-					    NUMA_NO_NODE, MEMBLOCK_NONE);
+	phys_addr_t ret;
+	ulong flags = choose_memblock_flags();
+
+again:
+	ret = memblock_find_in_range_node(size, align, start, end,
+					    NUMA_NO_NODE, flags);
+
+	if (!ret && (flags & MEMBLOCK_MIRROR)) {
+		pr_warn("Could not allocate %pap bytes of mirrored memory\n",
+			&size);
+		flags &= ~MEMBLOCK_MIRROR;
+		goto again;
+	}
+
+	return ret;
 }
 
 static void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r)
@@ -786,6 +805,21 @@ int __init_memblock memblock_clear_hotplug(phys_addr_t base, phys_addr_t size)
 }
 
 /**
+ * memblock_mark_mirror - Mark mirrored memory with flag MEMBLOCK_MIRROR.
+ * @base: the base phys addr of the region
+ * @size: the size of the region
+ *
+ * Return 0 on succees, -errno on failure.
+ */
+int __init_memblock memblock_mark_mirror(phys_addr_t base, phys_addr_t size)
+{
+	system_has_some_mirror = true;
+
+	return memblock_setclr_flag(base, size, 1, MEMBLOCK_MIRROR);
+}
+
+
+/**
  * __next__mem_range - next function for for_each_free_mem_range() etc.
  * @idx: pointer to u64 loop variable
  * @nid: node selector, %NUMA_NO_NODE for all nodes
@@ -839,6 +873,10 @@ void __init_memblock __next_mem_range(u64 *idx, int nid, ulong flags,
 		if (movable_node_is_enabled() && memblock_is_hotpluggable(m))
 			continue;
 
+		/* if we want mirror memory skip non-mirror memory regions */
+		if ((flags & MEMBLOCK_MIRROR) && !memblock_is_mirror(m))
+			continue;
+
 		if (!type_b) {
 			if (out_start)
 				*out_start = m_start;
@@ -944,6 +982,10 @@ void __init_memblock __next_mem_range_rev(u64 *idx, int nid, ulong flags,
 		if (movable_node_is_enabled() && memblock_is_hotpluggable(m))
 			continue;
 
+		/* if we want mirror memory skip non-mirror memory regions */
+		if ((flags & MEMBLOCK_MIRROR) && !memblock_is_mirror(m))
+			continue;
+
 		if (!type_b) {
 			if (out_start)
 				*out_start = m_start;
@@ -1096,8 +1138,18 @@ static phys_addr_t __init memblock_alloc_base_nid(phys_addr_t size,
 
 phys_addr_t __init memblock_alloc_nid(phys_addr_t size, phys_addr_t align, int nid)
 {
-	return memblock_alloc_base_nid(size, align, MEMBLOCK_ALLOC_ACCESSIBLE,
-				       nid, MEMBLOCK_NONE);
+	ulong flags = choose_memblock_flags();
+	phys_addr_t ret;
+
+again:
+	ret = memblock_alloc_base_nid(size, align, MEMBLOCK_ALLOC_ACCESSIBLE,
+				      nid, flags);
+
+	if (!ret && (flags & MEMBLOCK_MIRROR)) {
+		flags &= ~MEMBLOCK_MIRROR;
+		goto again;
+	}
+	return ret;
 }
 
 phys_addr_t __init __memblock_alloc_base(phys_addr_t size, phys_addr_t align, phys_addr_t max_addr)
@@ -1167,6 +1219,7 @@ static void * __init memblock_virt_alloc_internal(
 {
 	phys_addr_t alloc;
 	void *ptr;
+	ulong flags = choose_memblock_flags();
 
 	if (WARN_ONCE(nid == MAX_NUMNODES, "Usage of MAX_NUMNODES is deprecated. Use NUMA_NO_NODE instead\n"))
 		nid = NUMA_NO_NODE;
@@ -1187,14 +1240,14 @@ static void * __init memblock_virt_alloc_internal(
 
 again:
 	alloc = memblock_find_in_range_node(size, align, min_addr, max_addr,
-					    nid, MEMBLOCK_NONE);
+					    nid, flags);
 	if (alloc)
 		goto done;
 
 	if (nid != NUMA_NO_NODE) {
 		alloc = memblock_find_in_range_node(size, align, min_addr,
 						    max_addr, NUMA_NO_NODE,
-						    MEMBLOCK_NONE);
+						    flags);
 		if (alloc)
 			goto done;
 	}
@@ -1202,10 +1255,16 @@ again:
 	if (min_addr) {
 		min_addr = 0;
 		goto again;
-	} else {
-		goto error;
 	}
 
+	if (flags & MEMBLOCK_MIRROR) {
+		flags &= ~MEMBLOCK_MIRROR;
+		pr_warn("Could not allocate %pap bytes of mirrored memory\n",
+			&size);
+		goto again;
+	}
+
+	return NULL;
 done:
 	memblock_reserve(alloc, size);
 	ptr = phys_to_virt(alloc);
@@ -1220,9 +1279,6 @@ done:
 	kmemleak_alloc(ptr, size, 0, 0);
 
 	return ptr;
-
-error:
-	return NULL;
 }
 
 /**
diff --git a/mm/nobootmem.c b/mm/nobootmem.c
index ad3641dcdbe7..5258386fa1be 100644
--- a/mm/nobootmem.c
+++ b/mm/nobootmem.c
@@ -37,12 +37,20 @@ static void * __init __alloc_memory_core_early(int nid, u64 size, u64 align,
 {
 	void *ptr;
 	u64 addr;
+	ulong flags = choose_memblock_flags();
 
 	if (limit > memblock.current_limit)
 		limit = memblock.current_limit;
 
+again:
 	addr = memblock_find_in_range_node(size, align, goal, limit, nid,
-					   MEMBLOCK_NONE);
+					   flags);
+	if (!addr && (flags & MEMBLOCK_MIRROR)) {
+		flags &= ~MEMBLOCK_MIRROR;
+		pr_warn("Could not allocate %pap bytes of mirrored memory\n",
+			&size);
+		goto again;
+	}
 	if (!addr)
 		return NULL;
 
-- 
2.1.4

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