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authorJinyu Tang <tjytimi@163.com>2022-06-15 12:40:15 +0300
committerMike Rapoport <rppt@linux.ibm.com>2022-06-30 11:55:00 +0300
commit28e1a8f4b0ff1eafc320ec733b9c61ee7eb633ea (patch)
treec42f476f4b01620d39555d3bb504bedf4750d1b2 /mm/memblock.c
parent03c765b0e3b4cb5063276b086c76f7a612856a9a (diff)
downloadlinux-28e1a8f4b0ff1eafc320ec733b9c61ee7eb633ea.tar.xz
memblock: avoid some repeat when add new range
The worst case is that the new memory range overlaps all existing regions, which requires type->cnt + 1 empty struct memblock_region slots in the type->regions array. So if type->cnt + 1 + type->cnt is less than type->max, we can insert regions directly rather than calculate the needed amount before the insertion. And becase of merge operation in the end of function, tpye->cnt will increase slowly for many cases. This change allows to avoid unnecessary repeat of memblock ranges traversal for many cases when adding new memory range. Signed-off-by: Jinyu Tang <tjytimi@163.com> [rppt: massaged comment and changelog text] Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Diffstat (limited to 'mm/memblock.c')
-rw-r--r--mm/memblock.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/mm/memblock.c b/mm/memblock.c
index e4f03a6e8e56..16f006521afa 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -593,6 +593,17 @@ static int __init_memblock memblock_add_range(struct memblock_type *type,
type->total_size = size;
return 0;
}
+
+ /*
+ * The worst case is when new range overlaps all existing regions,
+ * then we'll need type->cnt + 1 empty regions in @type. So if
+ * type->cnt * 2 + 1 is less than type->max, we know
+ * that there is enough empty regions in @type, and we can insert
+ * regions directly.
+ */
+ if (type->cnt * 2 + 1 < type->max)
+ insert = true;
+
repeat:
/*
* The following is executed twice. Once with %false @insert and