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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-08-05 22:49:45 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2014-08-05 22:49:45 +0200
commitddbe8db147cd0954da93dc6986f4793bcabb3889 (patch)
tree0a0d463863ca78b644471132eb3f27ec3405b16d /kernel
parentb14c348e8dabcc7604683cfc44fad7396e8b639a (diff)
parent0f7d83e85dbd5bb8032ebed7713edf59670fb074 (diff)
Merge branch 'pm-sleep'
* pm-sleep: PM / Hibernate: Touch Soft Lockup Watchdog in rtree_next_node PM / Hibernate: Remove the old memory-bitmap implementation PM / Hibernate: Iterate over set bits instead of PFNs in swsusp_free() PM / Hibernate: Implement position keeping in radix tree PM / Hibernate: Add memory_rtree_find_bit function PM / Hibernate: Create a Radix-Tree to store memory bitmap PM / sleep: fix kernel-doc warnings in drivers/base/power/main.c
Diffstat (limited to 'kernel')
-rw-r--r--kernel/power/snapshot.c494
1 files changed, 367 insertions, 127 deletions
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 1ea328aafdc9..4fc5c32422b3 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -248,33 +248,61 @@ static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
* information is stored (in the form of a block of bitmap)
* It also contains the pfns that correspond to the start and end of
* the represented memory area.
+ *
+ * The memory bitmap is organized as a radix tree to guarantee fast random
+ * access to the bits. There is one radix tree for each zone (as returned
+ * from create_mem_extents).
+ *
+ * One radix tree is represented by one struct mem_zone_bm_rtree. There are
+ * two linked lists for the nodes of the tree, one for the inner nodes and
+ * one for the leave nodes. The linked leave nodes are used for fast linear
+ * access of the memory bitmap.
+ *
+ * The struct rtree_node represents one node of the radix tree.
*/
#define BM_END_OF_MAP (~0UL)
#define BM_BITS_PER_BLOCK (PAGE_SIZE * BITS_PER_BYTE)
+#define BM_BLOCK_SHIFT (PAGE_SHIFT + 3)
+#define BM_BLOCK_MASK ((1UL << BM_BLOCK_SHIFT) - 1)
-struct bm_block {
- struct list_head hook; /* hook into a list of bitmap blocks */
- unsigned long start_pfn; /* pfn represented by the first bit */
- unsigned long end_pfn; /* pfn represented by the last bit plus 1 */
- unsigned long *data; /* bitmap representing pages */
+/*
+ * struct rtree_node is a wrapper struct to link the nodes
+ * of the rtree together for easy linear iteration over
+ * bits and easy freeing
+ */
+struct rtree_node {
+ struct list_head list;
+ unsigned long *data;
};
-static inline unsigned long bm_block_bits(struct bm_block *bb)
-{
- return bb->end_pfn - bb->start_pfn;
-}
+/*
+ * struct mem_zone_bm_rtree represents a bitmap used for one
+ * populated memory zone.
+ */
+struct mem_zone_bm_rtree {
+ struct list_head list; /* Link Zones together */
+ struct list_head nodes; /* Radix Tree inner nodes */
+ struct list_head leaves; /* Radix Tree leaves */
+ unsigned long start_pfn; /* Zone start page frame */
+ unsigned long end_pfn; /* Zone end page frame + 1 */
+ struct rtree_node *rtree; /* Radix Tree Root */
+ int levels; /* Number of Radix Tree Levels */
+ unsigned int blocks; /* Number of Bitmap Blocks */
+};
/* strcut bm_position is used for browsing memory bitmaps */
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 {
- struct list_head blocks; /* list of bitmap blocks */
+ struct list_head zones;
struct linked_page *p_list; /* list of pages used to store zone
* bitmap objects and bitmap block
* objects
@@ -284,38 +312,178 @@ struct memory_bitmap {
/* Functions that operate on memory bitmaps */
-static void memory_bm_position_reset(struct memory_bitmap *bm)
+#define BM_ENTRIES_PER_LEVEL (PAGE_SIZE / sizeof(unsigned long))
+#if BITS_PER_LONG == 32
+#define BM_RTREE_LEVEL_SHIFT (PAGE_SHIFT - 2)
+#else
+#define BM_RTREE_LEVEL_SHIFT (PAGE_SHIFT - 3)
+#endif
+#define BM_RTREE_LEVEL_MASK ((1UL << BM_RTREE_LEVEL_SHIFT) - 1)
+
+/*
+ * alloc_rtree_node - Allocate a new node and add it to the radix tree.
+ *
+ * This function is used to allocate inner nodes as well as the
+ * leave nodes of the radix tree. It also adds the node to the
+ * corresponding linked list passed in by the *list parameter.
+ */
+static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed,
+ struct chain_allocator *ca,
+ struct list_head *list)
{
- bm->cur.block = list_entry(bm->blocks.next, struct bm_block, hook);
- bm->cur.bit = 0;
-}
+ struct rtree_node *node;
-static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
+ node = chain_alloc(ca, sizeof(struct rtree_node));
+ if (!node)
+ return NULL;
-/**
- * create_bm_block_list - create a list of block bitmap objects
- * @pages - number of pages to track
- * @list - list to put the allocated blocks into
- * @ca - chain allocator to be used for allocating memory
+ node->data = get_image_page(gfp_mask, safe_needed);
+ if (!node->data)
+ return NULL;
+
+ list_add_tail(&node->list, list);
+
+ return node;
+}
+
+/*
+ * add_rtree_block - Add a new leave node to the radix tree
+ *
+ * The leave nodes need to be allocated in order to keep the leaves
+ * linked list in order. This is guaranteed by the zone->blocks
+ * counter.
*/
-static int create_bm_block_list(unsigned long pages,
- struct list_head *list,
- struct chain_allocator *ca)
+static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask,
+ int safe_needed, struct chain_allocator *ca)
{
- unsigned int nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
+ struct rtree_node *node, *block, **dst;
+ unsigned int levels_needed, block_nr;
+ int i;
- while (nr_blocks-- > 0) {
- struct bm_block *bb;
+ block_nr = zone->blocks;
+ levels_needed = 0;
- bb = chain_alloc(ca, sizeof(struct bm_block));
- if (!bb)
+ /* How many levels do we need for this block nr? */
+ while (block_nr) {
+ levels_needed += 1;
+ block_nr >>= BM_RTREE_LEVEL_SHIFT;
+ }
+
+ /* Make sure the rtree has enough levels */
+ for (i = zone->levels; i < levels_needed; i++) {
+ node = alloc_rtree_node(gfp_mask, safe_needed, ca,
+ &zone->nodes);
+ if (!node)
return -ENOMEM;
- list_add(&bb->hook, list);
+
+ node->data[0] = (unsigned long)zone->rtree;
+ zone->rtree = node;
+ zone->levels += 1;
+ }
+
+ /* Allocate new block */
+ block = alloc_rtree_node(gfp_mask, safe_needed, ca, &zone->leaves);
+ if (!block)
+ return -ENOMEM;
+
+ /* Now walk the rtree to insert the block */
+ node = zone->rtree;
+ dst = &zone->rtree;
+ block_nr = zone->blocks;
+ for (i = zone->levels; i > 0; i--) {
+ int index;
+
+ if (!node) {
+ node = alloc_rtree_node(gfp_mask, safe_needed, ca,
+ &zone->nodes);
+ if (!node)
+ return -ENOMEM;
+ *dst = node;
+ }
+
+ index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
+ index &= BM_RTREE_LEVEL_MASK;
+ dst = (struct rtree_node **)&((*dst)->data[index]);
+ node = *dst;
}
+ zone->blocks += 1;
+ *dst = block;
+
return 0;
}
+static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
+ int clear_nosave_free);
+
+/*
+ * create_zone_bm_rtree - create a radix tree for one zone
+ *
+ * Allocated the mem_zone_bm_rtree structure and initializes it.
+ * This function also allocated and builds the radix tree for the
+ * zone.
+ */
+static struct mem_zone_bm_rtree *
+create_zone_bm_rtree(gfp_t gfp_mask, int safe_needed,
+ struct chain_allocator *ca,
+ unsigned long start, unsigned long end)
+{
+ struct mem_zone_bm_rtree *zone;
+ unsigned int i, nr_blocks;
+ unsigned long pages;
+
+ pages = end - start;
+ zone = chain_alloc(ca, sizeof(struct mem_zone_bm_rtree));
+ if (!zone)
+ return NULL;
+
+ INIT_LIST_HEAD(&zone->nodes);
+ INIT_LIST_HEAD(&zone->leaves);
+ zone->start_pfn = start;
+ zone->end_pfn = end;
+ nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
+
+ for (i = 0; i < nr_blocks; i++) {
+ if (add_rtree_block(zone, gfp_mask, safe_needed, ca)) {
+ free_zone_bm_rtree(zone, PG_UNSAFE_CLEAR);
+ return NULL;
+ }
+ }
+
+ return zone;
+}
+
+/*
+ * free_zone_bm_rtree - Free the memory of the radix tree
+ *
+ * Free all node pages of the radix tree. The mem_zone_bm_rtree
+ * structure itself is not freed here nor are the rtree_node
+ * structs.
+ */
+static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
+ int clear_nosave_free)
+{
+ struct rtree_node *node;
+
+ list_for_each_entry(node, &zone->nodes, list)
+ free_image_page(node->data, clear_nosave_free);
+
+ list_for_each_entry(node, &zone->leaves, list)
+ free_image_page(node->data, clear_nosave_free);
+}
+
+static void memory_bm_position_reset(struct memory_bitmap *bm)
+{
+ 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);
+
struct mem_extent {
struct list_head hook;
unsigned long start;
@@ -407,40 +575,22 @@ memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
int error;
chain_init(&ca, gfp_mask, safe_needed);
- INIT_LIST_HEAD(&bm->blocks);
+ INIT_LIST_HEAD(&bm->zones);
error = create_mem_extents(&mem_extents, gfp_mask);
if (error)
return error;
list_for_each_entry(ext, &mem_extents, hook) {
- struct bm_block *bb;
- unsigned long pfn = ext->start;
- unsigned long pages = ext->end - ext->start;
-
- bb = list_entry(bm->blocks.prev, struct bm_block, hook);
+ struct mem_zone_bm_rtree *zone;
- error = create_bm_block_list(pages, bm->blocks.prev, &ca);
- if (error)
+ zone = create_zone_bm_rtree(gfp_mask, safe_needed, &ca,
+ ext->start, ext->end);
+ if (!zone) {
+ error = -ENOMEM;
goto Error;
-
- list_for_each_entry_continue(bb, &bm->blocks, hook) {
- bb->data = get_image_page(gfp_mask, safe_needed);
- if (!bb->data) {
- error = -ENOMEM;
- goto Error;
- }
-
- bb->start_pfn = pfn;
- if (pages >= BM_BITS_PER_BLOCK) {
- pfn += BM_BITS_PER_BLOCK;
- pages -= BM_BITS_PER_BLOCK;
- } else {
- /* This is executed only once in the loop */
- pfn += pages;
- }
- bb->end_pfn = pfn;
}
+ list_add_tail(&zone->list, &bm->zones);
}
bm->p_list = ca.chain;
@@ -460,51 +610,83 @@ memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
*/
static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
{
- struct bm_block *bb;
+ struct mem_zone_bm_rtree *zone;
- list_for_each_entry(bb, &bm->blocks, hook)
- if (bb->data)
- free_image_page(bb->data, clear_nosave_free);
+ list_for_each_entry(zone, &bm->zones, list)
+ free_zone_bm_rtree(zone, clear_nosave_free);
free_list_of_pages(bm->p_list, clear_nosave_free);
- INIT_LIST_HEAD(&bm->blocks);
+ INIT_LIST_HEAD(&bm->zones);
}
/**
- * memory_bm_find_bit - find the bit in the bitmap @bm that corresponds
- * to given pfn. The cur_zone_bm member of @bm and the cur_block member
- * of @bm->cur_zone_bm are updated.
+ * memory_bm_find_bit - Find the bit for pfn in the memory
+ * bitmap
+ *
+ * Find the bit in the bitmap @bm that corresponds to given pfn.
+ * The cur.zone, cur.block and cur.node_pfn member of @bm are
+ * updated.
+ * It walks the radix tree to find the page which contains the bit for
+ * pfn and returns the bit position in **addr and *bit_nr.
*/
static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
- void **addr, unsigned int *bit_nr)
+ void **addr, unsigned int *bit_nr)
{
- struct bm_block *bb;
+ struct mem_zone_bm_rtree *curr, *zone;
+ 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 */
+ list_for_each_entry(curr, &bm->zones, list) {
+ if (pfn >= curr->start_pfn && pfn < curr->end_pfn) {
+ zone = curr;
+ break;
+ }
+ }
+
+ if (!zone)
+ return -EFAULT;
+
+zone_found:
/*
- * Check if the pfn corresponds to the current bitmap block and find
- * the block where it fits if this is not the case.
+ * We have a zone. Now walk the radix tree to find the leave
+ * node for our pfn.
*/
- bb = bm->cur.block;
- if (pfn < bb->start_pfn)
- list_for_each_entry_continue_reverse(bb, &bm->blocks, hook)
- if (pfn >= bb->start_pfn)
- break;
- if (pfn >= bb->end_pfn)
- list_for_each_entry_continue(bb, &bm->blocks, hook)
- if (pfn >= bb->start_pfn && pfn < bb->end_pfn)
- break;
+ node = bm->cur.node;
+ if (((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn)
+ goto node_found;
- if (&bb->hook == &bm->blocks)
- return -EFAULT;
+ node = zone->rtree;
+ block_nr = (pfn - zone->start_pfn) >> BM_BLOCK_SHIFT;
+
+ for (i = zone->levels; i > 0; i--) {
+ int index;
+
+ index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
+ index &= BM_RTREE_LEVEL_MASK;
+ BUG_ON(node->data[index] == 0);
+ 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;
- /* The block has been found */
- bm->cur.block = bb;
- pfn -= bb->start_pfn;
- bm->cur.bit = pfn + 1;
- *bit_nr = pfn;
- *addr = bb->data;
return 0;
}
@@ -528,6 +710,7 @@ static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
error = memory_bm_find_bit(bm, pfn, &addr, &bit);
if (!error)
set_bit(bit, addr);
+
return error;
}
@@ -542,6 +725,14 @@ static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
clear_bit(bit, addr);
}
+static void memory_bm_clear_current(struct memory_bitmap *bm)
+{
+ int bit;
+
+ bit = max(bm->cur.node_bit - 1, 0);
+ clear_bit(bit, bm->cur.node->data);
+}
+
static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
{
void *addr;
@@ -561,38 +752,70 @@ static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
return !memory_bm_find_bit(bm, pfn, &addr, &bit);
}
-/**
- * memory_bm_next_pfn - find the pfn that corresponds to the next set bit
- * in the bitmap @bm. If the pfn cannot be found, BM_END_OF_MAP is
- * returned.
+/*
+ * 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.
*
- * It is required to run memory_bm_position_reset() before the first call to
- * this function.
+ * 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;
+ touch_softlockup_watchdog();
+ 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 in the bitmap @bm
+ *
+ * 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.
+ *
+ * It is required to run memory_bm_position_reset() before the
+ * first call to this function.
+ */
static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
{
- struct bm_block *bb;
+ unsigned long bits, pfn, pages;
int bit;
- bb = bm->cur.block;
do {
- bit = bm->cur.bit;
- bit = find_next_bit(bb->data, bm_block_bits(bb), bit);
- if (bit < bm_block_bits(bb))
- goto Return_pfn;
-
- bb = list_entry(bb->hook.next, struct bm_block, hook);
- bm->cur.block = bb;
- bm->cur.bit = 0;
- } while (&bb->hook != &bm->blocks);
+ 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));
- memory_bm_position_reset(bm);
return BM_END_OF_MAP;
-
- Return_pfn:
- bm->cur.bit = bit + 1;
- return bb->start_pfn + bit;
}
/**
@@ -816,12 +1039,17 @@ void free_basic_memory_bitmaps(void)
unsigned int snapshot_additional_pages(struct zone *zone)
{
- unsigned int res;
+ unsigned int rtree, nodes;
+
+ rtree = nodes = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
+ rtree += DIV_ROUND_UP(rtree * sizeof(struct rtree_node),
+ LINKED_PAGE_DATA_SIZE);
+ while (nodes > 1) {
+ nodes = DIV_ROUND_UP(nodes, BM_ENTRIES_PER_LEVEL);
+ rtree += nodes;
+ }
- res = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
- res += DIV_ROUND_UP(res * sizeof(struct bm_block),
- LINKED_PAGE_DATA_SIZE);
- return 2 * res;
+ return 2 * rtree;
}
#ifdef CONFIG_HIGHMEM
@@ -1094,23 +1322,35 @@ static struct memory_bitmap copy_bm;
void swsusp_free(void)
{
- struct zone *zone;
- unsigned long pfn, max_zone_pfn;
+ unsigned long fb_pfn, fr_pfn;
- for_each_populated_zone(zone) {
- max_zone_pfn = zone_end_pfn(zone);
- for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
- if (pfn_valid(pfn)) {
- struct page *page = pfn_to_page(pfn);
-
- if (swsusp_page_is_forbidden(page) &&
- swsusp_page_is_free(page)) {
- swsusp_unset_page_forbidden(page);
- swsusp_unset_page_free(page);
- __free_page(page);
- }
- }
+ memory_bm_position_reset(forbidden_pages_map);
+ memory_bm_position_reset(free_pages_map);
+
+loop:
+ fr_pfn = memory_bm_next_pfn(free_pages_map);
+ fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
+
+ /*
+ * Find the next bit set in both bitmaps. This is guaranteed to
+ * terminate when fb_pfn == fr_pfn == BM_END_OF_MAP.
+ */
+ do {
+ if (fb_pfn < fr_pfn)
+ fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
+ if (fr_pfn < fb_pfn)
+ fr_pfn = memory_bm_next_pfn(free_pages_map);
+ } while (fb_pfn != fr_pfn);
+
+ if (fr_pfn != BM_END_OF_MAP && pfn_valid(fr_pfn)) {
+ struct page *page = pfn_to_page(fr_pfn);
+
+ memory_bm_clear_current(forbidden_pages_map);
+ memory_bm_clear_current(free_pages_map);
+ __free_page(page);
+ goto loop;
}
+
nr_copy_pages = 0;
nr_meta_pages = 0;
restore_pblist = NULL;