PM / Hibernate: Implement position keeping in radix tree
Add code to remember the last position that was requested in
the radix tree. Use it as a cache for faster linear walking
of the bitmap in the memory_bm_rtree_next_pfn() function
which is also added with this patch.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 0b7f934..802f241 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -309,6 +309,11 @@
struct bm_position {
struct bm_block *block;
int bit;
+
+ struct mem_zone_bm_rtree *zone;
+ struct rtree_node *node;
+ unsigned long node_pfn;
+ int node_bit;
};
struct memory_bitmap {
@@ -487,6 +492,13 @@
{
bm->cur.block = list_entry(bm->blocks.next, struct bm_block, hook);
bm->cur.bit = 0;
+
+ bm->cur.zone = list_entry(bm->zones.next, struct mem_zone_bm_rtree,
+ list);
+ bm->cur.node = list_entry(bm->cur.zone->leaves.next,
+ struct rtree_node, list);
+ bm->cur.node_pfn = 0;
+ bm->cur.node_bit = 0;
}
static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
@@ -734,6 +746,11 @@
struct rtree_node *node;
int i, block_nr;
+ zone = bm->cur.zone;
+
+ if (pfn >= zone->start_pfn && pfn < zone->end_pfn)
+ goto zone_found;
+
zone = NULL;
/* Find the right zone */
@@ -747,10 +764,16 @@
if (!zone)
return -EFAULT;
+zone_found:
/*
* We have a zone. Now walk the radix tree to find the leave
* node for our pfn.
*/
+
+ node = bm->cur.node;
+ if (((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn)
+ goto node_found;
+
node = zone->rtree;
block_nr = (pfn - zone->start_pfn) >> BM_BLOCK_SHIFT;
@@ -763,6 +786,12 @@
node = (struct rtree_node *)node->data[index];
}
+node_found:
+ /* Update last position */
+ bm->cur.zone = zone;
+ bm->cur.node = node;
+ bm->cur.node_pfn = (pfn - zone->start_pfn) & ~BM_BLOCK_MASK;
+
/* Set return values */
*addr = node->data;
*bit_nr = (pfn - zone->start_pfn) & BM_BLOCK_MASK;
@@ -860,11 +889,16 @@
* this function.
*/
+static unsigned long memory_bm_rtree_next_pfn(struct memory_bitmap *bm);
+
static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
{
+ unsigned long rtree_pfn;
struct bm_block *bb;
int bit;
+ rtree_pfn = memory_bm_rtree_next_pfn(bm);
+
bb = bm->cur.block;
do {
bit = bm->cur.bit;
@@ -878,13 +912,77 @@
} while (&bb->hook != &bm->blocks);
memory_bm_position_reset(bm);
+ WARN_ON_ONCE(rtree_pfn != BM_END_OF_MAP);
return BM_END_OF_MAP;
Return_pfn:
+ WARN_ON_ONCE(bb->start_pfn + bit != rtree_pfn);
bm->cur.bit = bit + 1;
return bb->start_pfn + bit;
}
+/*
+ * rtree_next_node - Jumps to the next leave node
+ *
+ * Sets the position to the beginning of the next node in the
+ * memory bitmap. This is either the next node in the current
+ * zone's radix tree or the first node in the radix tree of the
+ * next zone.
+ *
+ * Returns true if there is a next node, false otherwise.
+ */
+static bool rtree_next_node(struct memory_bitmap *bm)
+{
+ bm->cur.node = list_entry(bm->cur.node->list.next,
+ struct rtree_node, list);
+ if (&bm->cur.node->list != &bm->cur.zone->leaves) {
+ bm->cur.node_pfn += BM_BITS_PER_BLOCK;
+ bm->cur.node_bit = 0;
+ return true;
+ }
+
+ /* No more nodes, goto next zone */
+ bm->cur.zone = list_entry(bm->cur.zone->list.next,
+ struct mem_zone_bm_rtree, list);
+ if (&bm->cur.zone->list != &bm->zones) {
+ bm->cur.node = list_entry(bm->cur.zone->leaves.next,
+ struct rtree_node, list);
+ bm->cur.node_pfn = 0;
+ bm->cur.node_bit = 0;
+ return true;
+ }
+
+ /* No more zones */
+ return false;
+}
+
+/*
+ * memory_bm_rtree_next_pfn - Find the next set bit
+ *
+ * Starting from the last returned position this function searches
+ * for the next set bit in the memory bitmap and returns its
+ * number. If no more bit is set BM_END_OF_MAP is returned.
+ */
+static unsigned long memory_bm_rtree_next_pfn(struct memory_bitmap *bm)
+{
+ unsigned long bits, pfn, pages;
+ int bit;
+
+ do {
+ pages = bm->cur.zone->end_pfn - bm->cur.zone->start_pfn;
+ bits = min(pages - bm->cur.node_pfn, BM_BITS_PER_BLOCK);
+ bit = find_next_bit(bm->cur.node->data, bits,
+ bm->cur.node_bit);
+ if (bit < bits) {
+ pfn = bm->cur.zone->start_pfn + bm->cur.node_pfn + bit;
+ bm->cur.node_bit = bit + 1;
+ return pfn;
+ }
+ } while (rtree_next_node(bm));
+
+ return BM_END_OF_MAP;
+}
+
/**
* This structure represents a range of page frames the contents of which
* should not be saved during the suspend.