Re: [PATCH v3 06/13] memblock, numa: Introduce flag into memblock.

[Wanpeng Li <liwanp@linux.vnet.ibm.com>]

On Fri, May 24, 2013 at 05:29:15PM +0800, Tang Chen wrote:
>There is no flag in memblock to discribe what type the memory is.

s/discribe/describe

>Sometimes, we may use memblock to reserve some memory for special usage.
>For example, as Yinghai did in his patch, allocate pagetables on local
>node before all the memory on the node is mapped.
>Please refer to Yinghai's patch:
>v1: https://lkml.org/lkml/2013/3/7/642
>v2: https://lkml.org/lkml/2013/3/10/47
>v3: https://lkml.org/lkml/2013/4/4/639
>v4: https://lkml.org/lkml/2013/4/11/829
>
>In hotplug environment, there could be some problems when we hot-remove
>memory if we do so. Pagetable pages are kernel memory, which we cannot
>migrate. But we can put them in local node because their life-cycle is
>the same as the node.  So we need to free them all before memory hot-removing.
>
>Actually, data whose life cycle is the same as a node, such as pagetable
>pages, vmemmap pages, page_cgroup pages, all could be put on local node.
>They can be freed when we hot-removing a whole node.
>
>In order to do so, we need to mark out these special pages in memblock.
>In this patch, we introduce a new "flags" member into memblock_region:
>   struct memblock_region {
>           phys_addr_t base;
>           phys_addr_t size;
>           unsigned long flags;
>   #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
>           int nid;
>   #endif
>   };
>
>This patch does the following things:
>1) Add "flags" member to memblock_region, and MEMBLK_ANY flag for common usage.
>2) Modify the following APIs' prototype:
>	memblock_add_region()
>	memblock_insert_region()
>3) Add memblock_reserve_region() to support reserve memory with flags, and keep
>   memblock_reserve()'s prototype unmodified.
>4) Modify other APIs to support flags, but keep their prototype unmodified.
>
>The idea is from Wen Congyang <wency@cn.fujitsu.com> and Liu Jiang <jiang.liu@huawei.com>.
>
>Suggested-by: Wen Congyang <wency@cn.fujitsu.com>
>Suggested-by: Liu Jiang <jiang.liu@huawei.com>
>Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
>---
> include/linux/memblock.h |    8 ++++++
> mm/memblock.c            |   56 +++++++++++++++++++++++++++++++++------------
> 2 files changed, 49 insertions(+), 15 deletions(-)
>
>diff --git a/include/linux/memblock.h b/include/linux/memblock.h
>index f388203..c63a66e 100644
>--- a/include/linux/memblock.h
>+++ b/include/linux/memblock.h
>@@ -19,9 +19,17 @@
>
> #define INIT_MEMBLOCK_REGIONS	128
>
>+#define MEMBLK_FLAGS_DEFAULT	0
>+

MEMBLK_FLAGS_DEFAULT is one of the memblock flags, it should also include in 
memblock_flags emum.

>+/* Definition of memblock flags. */
>+enum memblock_flags {
>+	__NR_MEMBLK_FLAGS,	/* number of flags */
>+};
>+
> struct memblock_region {
> 	phys_addr_t base;
> 	phys_addr_t size;
>+	unsigned long flags;
> #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
> 	int nid;
> #endif
>diff --git a/mm/memblock.c b/mm/memblock.c
>index 16eda3d..63924ae 100644
>--- a/mm/memblock.c
>+++ b/mm/memblock.c
>@@ -157,6 +157,7 @@ static void __init_memblock memblock_remove_region(struct memblock_type *type, u
> 		type->cnt = 1;
> 		type->regions[0].base = 0;
> 		type->regions[0].size = 0;
>+		type->regions[0].flags = 0;
> 		memblock_set_region_node(&type->regions[0], MAX_NUMNODES);
> 	}
> }
>@@ -307,7 +308,8 @@ static void __init_memblock memblock_merge_regions(struct memblock_type *type)
>
> 		if (this->base + this->size != next->base ||
> 		    memblock_get_region_node(this) !=
>-		    memblock_get_region_node(next)) {
>+		    memblock_get_region_node(next) ||
>+		    this->flags != next->flags) {
> 			BUG_ON(this->base + this->size > next->base);
> 			i++;
> 			continue;
>@@ -327,13 +329,15 @@ static void __init_memblock memblock_merge_regions(struct memblock_type *type)
>  * @base:	base address of the new region
>  * @size:	size of the new region
>  * @nid:	node id of the new region
>+ * @flags:	flags of the new region
>  *
>  * Insert new memblock region [@base,@base+@size) into @type at @idx.
>  * @type must already have extra room to accomodate the new region.
>  */
> static void __init_memblock memblock_insert_region(struct memblock_type *type,
> 						   int idx, phys_addr_t base,
>-						   phys_addr_t size, int nid)
>+						   phys_addr_t size,
>+						   int nid, unsigned long flags)
> {
> 	struct memblock_region *rgn = &type->regions[idx];
>
>@@ -341,6 +345,7 @@ static void __init_memblock memblock_insert_region(struct memblock_type *type,
> 	memmove(rgn + 1, rgn, (type->cnt - idx) * sizeof(*rgn));
> 	rgn->base = base;
> 	rgn->size = size;
>+	rgn->flags = flags;
> 	memblock_set_region_node(rgn, nid);
> 	type->cnt++;
> 	type->total_size += size;
>@@ -352,6 +357,7 @@ static void __init_memblock memblock_insert_region(struct memblock_type *type,
>  * @base: base address of the new region
>  * @size: size of the new region
>  * @nid: nid of the new region
>+ * @flags: flags of the new region
>  *
>  * Add new memblock region [@base,@base+@size) into @type.  The new region
>  * is allowed to overlap with existing ones - overlaps don't affect already
>@@ -362,7 +368,8 @@ static void __init_memblock memblock_insert_region(struct memblock_type *type,
>  * 0 on success, -errno on failure.
>  */
> static int __init_memblock memblock_add_region(struct memblock_type *type,
>-				phys_addr_t base, phys_addr_t size, int nid)
>+				phys_addr_t base, phys_addr_t size,
>+				int nid, unsigned long flags)
> {
> 	bool insert = false;
> 	phys_addr_t obase = base;
>@@ -377,6 +384,7 @@ static int __init_memblock memblock_add_region(struct memblock_type *type,
> 		WARN_ON(type->cnt != 1 || type->total_size);
> 		type->regions[0].base = base;
> 		type->regions[0].size = size;
>+		type->regions[0].flags = flags;
> 		memblock_set_region_node(&type->regions[0], nid);
> 		type->total_size = size;
> 		return 0;
>@@ -407,7 +415,8 @@ repeat:
> 			nr_new++;
> 			if (insert)
> 				memblock_insert_region(type, i++, base,
>-						       rbase - base, nid);
>+						       rbase - base, nid,
>+						       flags);
> 		}
> 		/* area below @rend is dealt with, forget about it */
> 		base = min(rend, end);
>@@ -417,7 +426,8 @@ repeat:
> 	if (base < end) {
> 		nr_new++;
> 		if (insert)
>-			memblock_insert_region(type, i, base, end - base, nid);
>+			memblock_insert_region(type, i, base, end - base,
>+					       nid, flags);
> 	}
>
> 	/*
>@@ -439,12 +449,14 @@ repeat:
> int __init_memblock memblock_add_node(phys_addr_t base, phys_addr_t size,
> 				       int nid)
> {
>-	return memblock_add_region(&memblock.memory, base, size, nid);
>+	return memblock_add_region(&memblock.memory, base, size,
>+				   nid, MEMBLK_FLAGS_DEFAULT);
> }
>
> int __init_memblock memblock_add(phys_addr_t base, phys_addr_t size)
> {
>-	return memblock_add_region(&memblock.memory, base, size, MAX_NUMNODES);
>+	return memblock_add_region(&memblock.memory, base, size,
>+				   MAX_NUMNODES, MEMBLK_FLAGS_DEFAULT);
> }
>
> /**
>@@ -499,7 +511,8 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
> 			rgn->size -= base - rbase;
> 			type->total_size -= base - rbase;
> 			memblock_insert_region(type, i, rbase, base - rbase,
>-					       memblock_get_region_node(rgn));
>+					       memblock_get_region_node(rgn),
>+					       rgn->flags);
> 		} else if (rend > end) {
> 			/*
> 			 * @rgn intersects from above.  Split and redo the
>@@ -509,7 +522,8 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type,
> 			rgn->size -= end - rbase;
> 			type->total_size -= end - rbase;
> 			memblock_insert_region(type, i--, rbase, end - rbase,
>-					       memblock_get_region_node(rgn));
>+					       memblock_get_region_node(rgn),
>+					       rgn->flags);
> 		} else {
> 			/* @rgn is fully contained, record it */
> 			if (!*end_rgn)
>@@ -551,16 +565,25 @@ int __init_memblock memblock_free(phys_addr_t base, phys_addr_t size)
> 	return __memblock_remove(&memblock.reserved, base, size);
> }
>
>-int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
>+static int __init_memblock memblock_reserve_region(phys_addr_t base,
>+						   phys_addr_t size,
>+						   int nid,
>+						   unsigned long flags)
> {
> 	struct memblock_type *_rgn = &memblock.reserved;
>
>-	memblock_dbg("memblock_reserve: [%#016llx-%#016llx] %pF\n",
>+	memblock_dbg("memblock_reserve: [%#016llx-%#016llx] with flags %#016lx %pF\n",
> 		     (unsigned long long)base,
> 		     (unsigned long long)base + size,
>-		     (void *)_RET_IP_);
>+		     flags, (void *)_RET_IP_);
>+
>+	return memblock_add_region(_rgn, base, size, nid, flags);
>+}
>
>-	return memblock_add_region(_rgn, base, size, MAX_NUMNODES);
>+int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size)
>+{
>+	return memblock_reserve_region(base, size, MAX_NUMNODES,
>+				       MEMBLK_FLAGS_DEFAULT);
> }
>
> /**
>@@ -982,6 +1005,7 @@ void __init_memblock memblock_set_current_limit(phys_addr_t limit)
> static void __init_memblock memblock_dump(struct memblock_type *type, char *name)
> {
> 	unsigned long long base, size;
>+	unsigned long flags;
> 	int i;
>
> 	pr_info(" %s.cnt  = 0x%lx\n", name, type->cnt);
>@@ -992,13 +1016,15 @@ static void __init_memblock memblock_dump(struct memblock_type *type, char *name
>
> 		base = rgn->base;
> 		size = rgn->size;
>+		flags = rgn->flags;
> #ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
> 		if (memblock_get_region_node(rgn) != MAX_NUMNODES)
> 			snprintf(nid_buf, sizeof(nid_buf), " on node %d",
> 				 memblock_get_region_node(rgn));
> #endif
>-		pr_info(" %s[%#x]\t[%#016llx-%#016llx], %#llx bytes%s\n",
>-			name, i, base, base + size - 1, size, nid_buf);
>+		pr_info(" %s[%#x]\t[%#016llx-%#016llx], %#llx bytes%s "
>+			"flags: %#lx\n",
>+			name, i, base, base + size - 1, size, nid_buf, flags);
> 	}
> }
>
>-- 
>1.7.1
>
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