#include "percpu-internal.h"
-/* the slots are sorted by free bytes left, 1-31 bytes share the same slot */
+/*
+ * The slots are sorted by the size of the biggest continuous free area.
+ * 1-31 bytes share the same slot.
+ */
#define PCPU_SLOT_BASE_SHIFT 5
/* chunks in slots below this are subject to being sidelined on failed alloc */
#define PCPU_SLOT_FAIL_THRESHOLD 3
static int pcpu_nr_units __ro_after_init;
static int pcpu_atom_size __ro_after_init;
int pcpu_nr_slots __ro_after_init;
+static int pcpu_free_slot __ro_after_init;
+int pcpu_sidelined_slot __ro_after_init;
+int pcpu_to_depopulate_slot __ro_after_init;
static size_t pcpu_chunk_struct_size __ro_after_init;
/* cpus with the lowest and highest unit addresses */
static LIST_HEAD(pcpu_map_extend_chunks);
/*
- * The number of empty populated pages by chunk type, protected by pcpu_lock.
+ * The number of empty populated pages, protected by pcpu_lock.
* The reserved chunk doesn't contribute to the count.
*/
-int pcpu_nr_empty_pop_pages[PCPU_NR_CHUNK_TYPES];
+int pcpu_nr_empty_pop_pages;
/*
* The number of populated pages in use by the allocator, protected by
static int pcpu_size_to_slot(int size)
{
if (size == pcpu_unit_size)
- return pcpu_nr_slots - 1;
+ return pcpu_free_slot;
return __pcpu_size_to_slot(size);
}
return index * PCPU_BITMAP_BLOCK_BITS + off;
}
+/**
+ * pcpu_check_block_hint - check against the contig hint
+ * @block: block of interest
+ * @bits: size of allocation
+ * @align: alignment of area (max PAGE_SIZE)
+ *
+ * Check to see if the allocation can fit in the block's contig hint.
+ * Note, a chunk uses the same hints as a block so this can also check against
+ * the chunk's contig hint.
+ */
+static bool pcpu_check_block_hint(struct pcpu_block_md *block, int bits,
+ size_t align)
+{
+ int bit_off = ALIGN(block->contig_hint_start, align) -
+ block->contig_hint_start;
+
+ return bit_off + bits <= block->contig_hint;
+}
+
/*
* pcpu_next_hint - determine which hint to use
* @block: block of interest
bool move_front)
{
if (chunk != pcpu_reserved_chunk) {
- struct list_head *pcpu_slot;
-
- pcpu_slot = pcpu_chunk_list(pcpu_chunk_type(chunk));
if (move_front)
- list_move(&chunk->list, &pcpu_slot[slot]);
+ list_move(&chunk->list, &pcpu_chunk_lists[slot]);
else
- list_move_tail(&chunk->list, &pcpu_slot[slot]);
+ list_move_tail(&chunk->list, &pcpu_chunk_lists[slot]);
}
}
{
int nslot = pcpu_chunk_slot(chunk);
+ /* leave isolated chunks in-place */
+ if (chunk->isolated)
+ return;
+
if (oslot != nslot)
__pcpu_chunk_move(chunk, nslot, oslot < nslot);
}
+static void pcpu_isolate_chunk(struct pcpu_chunk *chunk)
+{
+ lockdep_assert_held(&pcpu_lock);
+
+ if (!chunk->isolated) {
+ chunk->isolated = true;
+ pcpu_nr_empty_pop_pages -= chunk->nr_empty_pop_pages;
+ }
+ list_move(&chunk->list, &pcpu_chunk_lists[pcpu_to_depopulate_slot]);
+}
+
+static void pcpu_reintegrate_chunk(struct pcpu_chunk *chunk)
+{
+ lockdep_assert_held(&pcpu_lock);
+
+ if (chunk->isolated) {
+ chunk->isolated = false;
+ pcpu_nr_empty_pop_pages += chunk->nr_empty_pop_pages;
+ pcpu_chunk_relocate(chunk, -1);
+ }
+}
+
/*
* pcpu_update_empty_pages - update empty page counters
* @chunk: chunk of interest
static inline void pcpu_update_empty_pages(struct pcpu_chunk *chunk, int nr)
{
chunk->nr_empty_pop_pages += nr;
- if (chunk != pcpu_reserved_chunk)
- pcpu_nr_empty_pop_pages[pcpu_chunk_type(chunk)] += nr;
+ if (chunk != pcpu_reserved_chunk && !chunk->isolated)
+ pcpu_nr_empty_pop_pages += nr;
}
/*
int bit_off, bits, next_off;
/*
- * Check to see if the allocation can fit in the chunk's contig hint.
- * This is an optimization to prevent scanning by assuming if it
- * cannot fit in the global hint, there is memory pressure and creating
- * a new chunk would happen soon.
+ * This is an optimization to prevent scanning by assuming if the
+ * allocation cannot fit in the global hint, there is memory pressure
+ * and creating a new chunk would happen soon.
*/
- bit_off = ALIGN(chunk_md->contig_hint_start, align) -
- chunk_md->contig_hint_start;
- if (bit_off + alloc_bits > chunk_md->contig_hint)
+ if (!pcpu_check_block_hint(chunk_md, alloc_bits, align))
return -1;
bit_off = pcpu_next_hint(chunk_md, alloc_bits);
alloc_size);
#ifdef CONFIG_MEMCG_KMEM
- /* first chunk isn't memcg-aware */
+ /* first chunk is free to use */
chunk->obj_cgroups = NULL;
#endif
pcpu_init_md_blocks(chunk);
return chunk;
}
-static struct pcpu_chunk *pcpu_alloc_chunk(enum pcpu_chunk_type type, gfp_t gfp)
+static struct pcpu_chunk *pcpu_alloc_chunk(gfp_t gfp)
{
struct pcpu_chunk *chunk;
int region_bits;
goto md_blocks_fail;
#ifdef CONFIG_MEMCG_KMEM
- if (pcpu_is_memcg_chunk(type)) {
+ if (!mem_cgroup_kmem_disabled()) {
chunk->obj_cgroups =
pcpu_mem_zalloc(pcpu_chunk_map_bits(chunk) *
sizeof(struct obj_cgroup *), gfp);
int page_start, int page_end, gfp_t gfp);
static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
int page_start, int page_end);
-static struct pcpu_chunk *pcpu_create_chunk(enum pcpu_chunk_type type,
- gfp_t gfp);
+static struct pcpu_chunk *pcpu_create_chunk(gfp_t gfp);
static void pcpu_destroy_chunk(struct pcpu_chunk *chunk);
static struct page *pcpu_addr_to_page(void *addr);
static int __init pcpu_verify_alloc_info(const struct pcpu_alloc_info *ai);
}
#ifdef CONFIG_MEMCG_KMEM
-static enum pcpu_chunk_type pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp,
- struct obj_cgroup **objcgp)
+static bool pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp,
+ struct obj_cgroup **objcgp)
{
struct obj_cgroup *objcg;
if (!memcg_kmem_enabled() || !(gfp & __GFP_ACCOUNT))
- return PCPU_CHUNK_ROOT;
+ return true;
objcg = get_obj_cgroup_from_current();
if (!objcg)
- return PCPU_CHUNK_ROOT;
+ return true;
if (obj_cgroup_charge(objcg, gfp, size * num_possible_cpus())) {
obj_cgroup_put(objcg);
- return PCPU_FAIL_ALLOC;
+ return false;
}
*objcgp = objcg;
- return PCPU_CHUNK_MEMCG;
+ return true;
}
static void pcpu_memcg_post_alloc_hook(struct obj_cgroup *objcg,
if (!objcg)
return;
- if (chunk) {
+ if (likely(chunk && chunk->obj_cgroups)) {
chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = objcg;
rcu_read_lock();
{
struct obj_cgroup *objcg;
- if (!pcpu_is_memcg_chunk(pcpu_chunk_type(chunk)))
+ if (unlikely(!chunk->obj_cgroups))
return;
objcg = chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT];
+ if (!objcg)
+ return;
chunk->obj_cgroups[off >> PCPU_MIN_ALLOC_SHIFT] = NULL;
obj_cgroup_uncharge(objcg, size * num_possible_cpus());
}
#else /* CONFIG_MEMCG_KMEM */
-static enum pcpu_chunk_type
+static bool
pcpu_memcg_pre_alloc_hook(size_t size, gfp_t gfp, struct obj_cgroup **objcgp)
{
- return PCPU_CHUNK_ROOT;
+ return true;
}
static void pcpu_memcg_post_alloc_hook(struct obj_cgroup *objcg,
gfp_t pcpu_gfp;
bool is_atomic;
bool do_warn;
- enum pcpu_chunk_type type;
- struct list_head *pcpu_slot;
struct obj_cgroup *objcg = NULL;
static int warn_limit = 10;
struct pcpu_chunk *chunk, *next;
return NULL;
}
- type = pcpu_memcg_pre_alloc_hook(size, gfp, &objcg);
- if (unlikely(type == PCPU_FAIL_ALLOC))
+ if (unlikely(!pcpu_memcg_pre_alloc_hook(size, gfp, &objcg)))
return NULL;
- pcpu_slot = pcpu_chunk_list(type);
if (!is_atomic) {
/*
restart:
/* search through normal chunks */
- for (slot = pcpu_size_to_slot(size); slot < pcpu_nr_slots; slot++) {
- list_for_each_entry_safe(chunk, next, &pcpu_slot[slot], list) {
+ for (slot = pcpu_size_to_slot(size); slot <= pcpu_free_slot; slot++) {
+ list_for_each_entry_safe(chunk, next, &pcpu_chunk_lists[slot],
+ list) {
off = pcpu_find_block_fit(chunk, bits, bit_align,
is_atomic);
if (off < 0) {
}
off = pcpu_alloc_area(chunk, bits, bit_align, off);
- if (off >= 0)
+ if (off >= 0) {
+ pcpu_reintegrate_chunk(chunk);
goto area_found;
-
+ }
}
}
goto fail;
}
- if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
- chunk = pcpu_create_chunk(type, pcpu_gfp);
+ if (list_empty(&pcpu_chunk_lists[pcpu_free_slot])) {
+ chunk = pcpu_create_chunk(pcpu_gfp);
if (!chunk) {
err = "failed to allocate new chunk";
goto fail;
mutex_unlock(&pcpu_alloc_mutex);
}
- if (pcpu_nr_empty_pop_pages[type] < PCPU_EMPTY_POP_PAGES_LOW)
+ if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_LOW)
pcpu_schedule_balance_work();
/* clear the areas and return address relative to base address */
}
/**
- * __pcpu_balance_workfn - manage the amount of free chunks and populated pages
- * @type: chunk type
+ * pcpu_balance_free - manage the amount of free chunks
+ * @empty_only: free chunks only if there are no populated pages
*
- * Reclaim all fully free chunks except for the first one. This is also
- * responsible for maintaining the pool of empty populated pages. However,
- * it is possible that this is called when physical memory is scarce causing
- * OOM killer to be triggered. We should avoid doing so until an actual
- * allocation causes the failure as it is possible that requests can be
- * serviced from already backed regions.
+ * If empty_only is %false, reclaim all fully free chunks regardless of the
+ * number of populated pages. Otherwise, only reclaim chunks that have no
+ * populated pages.
+ *
+ * CONTEXT:
+ * pcpu_lock (can be dropped temporarily)
*/
-static void __pcpu_balance_workfn(enum pcpu_chunk_type type)
+static void pcpu_balance_free(bool empty_only)
{
- /* gfp flags passed to underlying allocators */
- const gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
LIST_HEAD(to_free);
- struct list_head *pcpu_slot = pcpu_chunk_list(type);
- struct list_head *free_head = &pcpu_slot[pcpu_nr_slots - 1];
+ struct list_head *free_head = &pcpu_chunk_lists[pcpu_free_slot];
struct pcpu_chunk *chunk, *next;
- int slot, nr_to_pop, ret;
+
+ lockdep_assert_held(&pcpu_lock);
/*
* There's no reason to keep around multiple unused chunks and VM
* areas can be scarce. Destroy all free chunks except for one.
*/
- mutex_lock(&pcpu_alloc_mutex);
- spin_lock_irq(&pcpu_lock);
-
list_for_each_entry_safe(chunk, next, free_head, list) {
WARN_ON(chunk->immutable);
if (chunk == list_first_entry(free_head, struct pcpu_chunk, list))
continue;
- list_move(&chunk->list, &to_free);
+ if (!empty_only || chunk->nr_empty_pop_pages == 0)
+ list_move(&chunk->list, &to_free);
}
- spin_unlock_irq(&pcpu_lock);
+ if (list_empty(&to_free))
+ return;
+ spin_unlock_irq(&pcpu_lock);
list_for_each_entry_safe(chunk, next, &to_free, list) {
unsigned int rs, re;
pcpu_destroy_chunk(chunk);
cond_resched();
}
+ spin_lock_irq(&pcpu_lock);
+}
+
+/**
+ * pcpu_balance_populated - manage the amount of populated pages
+ *
+ * Maintain a certain amount of populated pages to satisfy atomic allocations.
+ * It is possible that this is called when physical memory is scarce causing
+ * OOM killer to be triggered. We should avoid doing so until an actual
+ * allocation causes the failure as it is possible that requests can be
+ * serviced from already backed regions.
+ *
+ * CONTEXT:
+ * pcpu_lock (can be dropped temporarily)
+ */
+static void pcpu_balance_populated(void)
+{
+ /* gfp flags passed to underlying allocators */
+ const gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
+ struct pcpu_chunk *chunk;
+ int slot, nr_to_pop, ret;
+
+ lockdep_assert_held(&pcpu_lock);
/*
* Ensure there are certain number of free populated pages for
pcpu_atomic_alloc_failed = false;
} else {
nr_to_pop = clamp(PCPU_EMPTY_POP_PAGES_HIGH -
- pcpu_nr_empty_pop_pages[type],
+ pcpu_nr_empty_pop_pages,
0, PCPU_EMPTY_POP_PAGES_HIGH);
}
- for (slot = pcpu_size_to_slot(PAGE_SIZE); slot < pcpu_nr_slots; slot++) {
+ for (slot = pcpu_size_to_slot(PAGE_SIZE); slot <= pcpu_free_slot; slot++) {
unsigned int nr_unpop = 0, rs, re;
if (!nr_to_pop)
break;
- spin_lock_irq(&pcpu_lock);
- list_for_each_entry(chunk, &pcpu_slot[slot], list) {
+ list_for_each_entry(chunk, &pcpu_chunk_lists[slot], list) {
nr_unpop = chunk->nr_pages - chunk->nr_populated;
if (nr_unpop)
break;
}
- spin_unlock_irq(&pcpu_lock);
if (!nr_unpop)
continue;
chunk->nr_pages) {
int nr = min_t(int, re - rs, nr_to_pop);
+ spin_unlock_irq(&pcpu_lock);
ret = pcpu_populate_chunk(chunk, rs, rs + nr, gfp);
+ cond_resched();
+ spin_lock_irq(&pcpu_lock);
if (!ret) {
nr_to_pop -= nr;
- spin_lock_irq(&pcpu_lock);
pcpu_chunk_populated(chunk, rs, rs + nr);
- spin_unlock_irq(&pcpu_lock);
} else {
nr_to_pop = 0;
}
if (nr_to_pop) {
/* ran out of chunks to populate, create a new one and retry */
- chunk = pcpu_create_chunk(type, gfp);
+ spin_unlock_irq(&pcpu_lock);
+ chunk = pcpu_create_chunk(gfp);
+ cond_resched();
+ spin_lock_irq(&pcpu_lock);
if (chunk) {
- spin_lock_irq(&pcpu_lock);
pcpu_chunk_relocate(chunk, -1);
- spin_unlock_irq(&pcpu_lock);
goto retry_pop;
}
}
+}
- mutex_unlock(&pcpu_alloc_mutex);
+/**
+ * pcpu_reclaim_populated - scan over to_depopulate chunks and free empty pages
+ *
+ * Scan over chunks in the depopulate list and try to release unused populated
+ * pages back to the system. Depopulated chunks are sidelined to prevent
+ * repopulating these pages unless required. Fully free chunks are reintegrated
+ * and freed accordingly (1 is kept around). If we drop below the empty
+ * populated pages threshold, reintegrate the chunk if it has empty free pages.
+ * Each chunk is scanned in the reverse order to keep populated pages close to
+ * the beginning of the chunk.
+ *
+ * CONTEXT:
+ * pcpu_lock (can be dropped temporarily)
+ *
+ */
+static void pcpu_reclaim_populated(void)
+{
+ struct pcpu_chunk *chunk;
+ struct pcpu_block_md *block;
+ int i, end;
+
+ lockdep_assert_held(&pcpu_lock);
+
+restart:
+ /*
+ * Once a chunk is isolated to the to_depopulate list, the chunk is no
+ * longer discoverable to allocations whom may populate pages. The only
+ * other accessor is the free path which only returns area back to the
+ * allocator not touching the populated bitmap.
+ */
+ while (!list_empty(&pcpu_chunk_lists[pcpu_to_depopulate_slot])) {
+ chunk = list_first_entry(&pcpu_chunk_lists[pcpu_to_depopulate_slot],
+ struct pcpu_chunk, list);
+ WARN_ON(chunk->immutable);
+
+ /*
+ * Scan chunk's pages in the reverse order to keep populated
+ * pages close to the beginning of the chunk.
+ */
+ for (i = chunk->nr_pages - 1, end = -1; i >= 0; i--) {
+ /* no more work to do */
+ if (chunk->nr_empty_pop_pages == 0)
+ break;
+
+ /* reintegrate chunk to prevent atomic alloc failures */
+ if (pcpu_nr_empty_pop_pages < PCPU_EMPTY_POP_PAGES_HIGH) {
+ pcpu_reintegrate_chunk(chunk);
+ goto restart;
+ }
+
+ /*
+ * If the page is empty and populated, start or
+ * extend the (i, end) range. If i == 0, decrease
+ * i and perform the depopulation to cover the last
+ * (first) page in the chunk.
+ */
+ block = chunk->md_blocks + i;
+ if (block->contig_hint == PCPU_BITMAP_BLOCK_BITS &&
+ test_bit(i, chunk->populated)) {
+ if (end == -1)
+ end = i;
+ if (i > 0)
+ continue;
+ i--;
+ }
+
+ /* depopulate if there is an active range */
+ if (end == -1)
+ continue;
+
+ spin_unlock_irq(&pcpu_lock);
+ pcpu_depopulate_chunk(chunk, i + 1, end + 1);
+ cond_resched();
+ spin_lock_irq(&pcpu_lock);
+
+ pcpu_chunk_depopulated(chunk, i + 1, end + 1);
+
+ /* reset the range and continue */
+ end = -1;
+ }
+
+ if (chunk->free_bytes == pcpu_unit_size)
+ pcpu_reintegrate_chunk(chunk);
+ else
+ list_move(&chunk->list,
+ &pcpu_chunk_lists[pcpu_sidelined_slot]);
+ }
}
/**
* pcpu_balance_workfn - manage the amount of free chunks and populated pages
* @work: unused
*
- * Call __pcpu_balance_workfn() for each chunk type.
+ * For each chunk type, manage the number of fully free chunks and the number of
+ * populated pages. An important thing to consider is when pages are freed and
+ * how they contribute to the global counts.
*/
static void pcpu_balance_workfn(struct work_struct *work)
{
- enum pcpu_chunk_type type;
+ /*
+ * pcpu_balance_free() is called twice because the first time we may
+ * trim pages in the active pcpu_nr_empty_pop_pages which may cause us
+ * to grow other chunks. This then gives pcpu_reclaim_populated() time
+ * to move fully free chunks to the active list to be freed if
+ * appropriate.
+ */
+ mutex_lock(&pcpu_alloc_mutex);
+ spin_lock_irq(&pcpu_lock);
+
+ pcpu_balance_free(false);
+ pcpu_reclaim_populated();
+ pcpu_balance_populated();
+ pcpu_balance_free(true);
- for (type = 0; type < PCPU_NR_CHUNK_TYPES; type++)
- __pcpu_balance_workfn(type);
+ spin_unlock_irq(&pcpu_lock);
+ mutex_unlock(&pcpu_alloc_mutex);
}
/**
unsigned long flags;
int size, off;
bool need_balance = false;
- struct list_head *pcpu_slot;
if (!ptr)
return;
size = pcpu_free_area(chunk, off);
- pcpu_slot = pcpu_chunk_list(pcpu_chunk_type(chunk));
-
pcpu_memcg_free_hook(chunk, off, size);
- /* if there are more than one fully free chunks, wake up grim reaper */
- if (chunk->free_bytes == pcpu_unit_size) {
+ /*
+ * If there are more than one fully free chunks, wake up grim reaper.
+ * If the chunk is isolated, it may be in the process of being
+ * reclaimed. Let reclaim manage cleaning up of that chunk.
+ */
+ if (!chunk->isolated && chunk->free_bytes == pcpu_unit_size) {
struct pcpu_chunk *pos;
- list_for_each_entry(pos, &pcpu_slot[pcpu_nr_slots - 1], list)
+ list_for_each_entry(pos, &pcpu_chunk_lists[pcpu_free_slot], list)
if (pos != chunk) {
need_balance = true;
break;
}
+ } else if (pcpu_should_reclaim_chunk(chunk)) {
+ pcpu_isolate_chunk(chunk);
+ need_balance = true;
}
trace_percpu_free_percpu(chunk->base_addr, off, ptr);
int map_size;
unsigned long tmp_addr;
size_t alloc_size;
- enum pcpu_chunk_type type;
#define PCPU_SETUP_BUG_ON(cond) do { \
if (unlikely(cond)) { \
pcpu_stats_save_ai(ai);
/*
- * Allocate chunk slots. The additional last slot is for
- * empty chunks.
+ * Allocate chunk slots. The slots after the active slots are:
+ * sidelined_slot - isolated, depopulated chunks
+ * free_slot - fully free chunks
+ * to_depopulate_slot - isolated, chunks to depopulate
*/
- pcpu_nr_slots = __pcpu_size_to_slot(pcpu_unit_size) + 2;
+ pcpu_sidelined_slot = __pcpu_size_to_slot(pcpu_unit_size) + 1;
+ pcpu_free_slot = pcpu_sidelined_slot + 1;
+ pcpu_to_depopulate_slot = pcpu_free_slot + 1;
+ pcpu_nr_slots = pcpu_to_depopulate_slot + 1;
pcpu_chunk_lists = memblock_alloc(pcpu_nr_slots *
- sizeof(pcpu_chunk_lists[0]) *
- PCPU_NR_CHUNK_TYPES,
+ sizeof(pcpu_chunk_lists[0]),
SMP_CACHE_BYTES);
if (!pcpu_chunk_lists)
panic("%s: Failed to allocate %zu bytes\n", __func__,
- pcpu_nr_slots * sizeof(pcpu_chunk_lists[0]) *
- PCPU_NR_CHUNK_TYPES);
+ pcpu_nr_slots * sizeof(pcpu_chunk_lists[0]));
- for (type = 0; type < PCPU_NR_CHUNK_TYPES; type++)
- for (i = 0; i < pcpu_nr_slots; i++)
- INIT_LIST_HEAD(&pcpu_chunk_list(type)[i]);
+ for (i = 0; i < pcpu_nr_slots; i++)
+ INIT_LIST_HEAD(&pcpu_chunk_lists[i]);
/*
* The end of the static region needs to be aligned with the
/* link the first chunk in */
pcpu_first_chunk = chunk;
- pcpu_nr_empty_pop_pages[PCPU_CHUNK_ROOT] = pcpu_first_chunk->nr_empty_pop_pages;
+ pcpu_nr_empty_pop_pages = pcpu_first_chunk->nr_empty_pop_pages;
pcpu_chunk_relocate(pcpu_first_chunk, -1);
/* include all regions of the first chunk */
* Related to atom_size, which could be much larger than the unit_size.
*/
last_allocs = INT_MAX;
+ best_upa = 0;
for (upa = max_upa; upa; upa--) {
int allocs = 0, wasted = 0;
last_allocs = allocs;
best_upa = upa;
}
+ BUG_ON(!best_upa);
upa = best_upa;
/* allocate and fill alloc_info */
projects / linux-block.git / commitdiff