Merge branch 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
* 'slab/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
tools, slub: Fix off-by-one buffer corruption after readlink() call
slub: Discard slab page when node partial > minimum partial number
slub: correct comments error for per cpu partial
mm: restrict access to slab files under procfs and sysfs
slub: Code optimization in get_partial_node()
slub: doc: update the slabinfo.c file path
slub: explicitly document position of inserting slab to partial list
slub: update slabinfo tools to report per cpu partial list statistics
slub: per cpu cache for partial pages
slub: return object pointer from get_partial() / new_slab().
slub: pass kmem_cache_cpu pointer to get_partial()
slub: Prepare inuse field in new_slab()
slub: Remove useless statements in __slab_alloc
slub: free slabs without holding locks
slub: use print_hex_dump
slab: use print_hex_dump
diff --git a/Documentation/vm/00-INDEX b/Documentation/vm/00-INDEX
index dca82d7..5481c8b 100644
--- a/Documentation/vm/00-INDEX
+++ b/Documentation/vm/00-INDEX
@@ -30,8 +30,6 @@
- description of page migration in NUMA systems.
pagemap.txt
- pagemap, from the userspace perspective
-slabinfo.c
- - source code for a tool to get reports about slabs.
slub.txt
- a short users guide for SLUB.
unevictable-lru.txt
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 29971a5..c93d00a 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -79,9 +79,21 @@
};
/* Third double word block */
- struct list_head lru; /* Pageout list, eg. active_list
+ union {
+ struct list_head lru; /* Pageout list, eg. active_list
* protected by zone->lru_lock !
*/
+ struct { /* slub per cpu partial pages */
+ struct page *next; /* Next partial slab */
+#ifdef CONFIG_64BIT
+ int pages; /* Nr of partial slabs left */
+ int pobjects; /* Approximate # of objects */
+#else
+ short int pages;
+ short int pobjects;
+#endif
+ };
+ };
/* Remainder is not double word aligned */
union {
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index f58d641..a32bcfd 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -36,12 +36,15 @@
ORDER_FALLBACK, /* Number of times fallback was necessary */
CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
CMPXCHG_DOUBLE_FAIL, /* Number of times that cmpxchg double did not match */
+ CPU_PARTIAL_ALLOC, /* Used cpu partial on alloc */
+ CPU_PARTIAL_FREE, /* USed cpu partial on free */
NR_SLUB_STAT_ITEMS };
struct kmem_cache_cpu {
void **freelist; /* Pointer to next available object */
unsigned long tid; /* Globally unique transaction id */
struct page *page; /* The slab from which we are allocating */
+ struct page *partial; /* Partially allocated frozen slabs */
int node; /* The node of the page (or -1 for debug) */
#ifdef CONFIG_SLUB_STATS
unsigned stat[NR_SLUB_STAT_ITEMS];
@@ -79,6 +82,7 @@
int size; /* The size of an object including meta data */
int objsize; /* The size of an object without meta data */
int offset; /* Free pointer offset. */
+ int cpu_partial; /* Number of per cpu partial objects to keep around */
struct kmem_cache_order_objects oo;
/* Allocation and freeing of slabs */
diff --git a/mm/slab.c b/mm/slab.c
index 6d90a09..708efe8 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1851,15 +1851,15 @@
unsigned char error = 0;
int bad_count = 0;
- printk(KERN_ERR "%03x:", offset);
+ printk(KERN_ERR "%03x: ", offset);
for (i = 0; i < limit; i++) {
if (data[offset + i] != POISON_FREE) {
error = data[offset + i];
bad_count++;
}
- printk(" %02x", (unsigned char)data[offset + i]);
}
- printk("\n");
+ print_hex_dump(KERN_CONT, "", 0, 16, 1,
+ &data[offset], limit, 1);
if (bad_count == 1) {
error ^= POISON_FREE;
@@ -3039,14 +3039,9 @@
printk(KERN_ERR "slab: Internal list corruption detected in "
"cache '%s'(%d), slabp %p(%d). Hexdump:\n",
cachep->name, cachep->num, slabp, slabp->inuse);
- for (i = 0;
- i < sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t);
- i++) {
- if (i % 16 == 0)
- printk("\n%03x:", i);
- printk(" %02x", ((unsigned char *)slabp)[i]);
- }
- printk("\n");
+ print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, slabp,
+ sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t),
+ 1);
BUG();
}
}
@@ -4584,7 +4579,7 @@
static int __init slab_proc_init(void)
{
- proc_create("slabinfo",S_IWUSR|S_IRUGO,NULL,&proc_slabinfo_operations);
+ proc_create("slabinfo",S_IWUSR|S_IRUSR,NULL,&proc_slabinfo_operations);
#ifdef CONFIG_DEBUG_SLAB_LEAK
proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
#endif
diff --git a/mm/slub.c b/mm/slub.c
index 7c54fe8..95215aa 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -467,34 +467,8 @@
*/
static void print_section(char *text, u8 *addr, unsigned int length)
{
- int i, offset;
- int newline = 1;
- char ascii[17];
-
- ascii[16] = 0;
-
- for (i = 0; i < length; i++) {
- if (newline) {
- printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
- newline = 0;
- }
- printk(KERN_CONT " %02x", addr[i]);
- offset = i % 16;
- ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
- if (offset == 15) {
- printk(KERN_CONT " %s\n", ascii);
- newline = 1;
- }
- }
- if (!newline) {
- i %= 16;
- while (i < 16) {
- printk(KERN_CONT " ");
- ascii[i] = ' ';
- i++;
- }
- printk(KERN_CONT " %s\n", ascii);
- }
+ print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
+ length, 1);
}
static struct track *get_track(struct kmem_cache *s, void *object,
@@ -625,12 +599,12 @@
p, p - addr, get_freepointer(s, p));
if (p > addr + 16)
- print_section("Bytes b4", p - 16, 16);
+ print_section("Bytes b4 ", p - 16, 16);
- print_section("Object", p, min_t(unsigned long, s->objsize, PAGE_SIZE));
-
+ print_section("Object ", p, min_t(unsigned long, s->objsize,
+ PAGE_SIZE));
if (s->flags & SLAB_RED_ZONE)
- print_section("Redzone", p + s->objsize,
+ print_section("Redzone ", p + s->objsize,
s->inuse - s->objsize);
if (s->offset)
@@ -643,7 +617,7 @@
if (off != s->size)
/* Beginning of the filler is the free pointer */
- print_section("Padding", p + off, s->size - off);
+ print_section("Padding ", p + off, s->size - off);
dump_stack();
}
@@ -838,7 +812,7 @@
end--;
slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
- print_section("Padding", end - remainder, remainder);
+ print_section("Padding ", end - remainder, remainder);
restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
return 0;
@@ -987,7 +961,7 @@
page->freelist);
if (!alloc)
- print_section("Object", (void *)object, s->objsize);
+ print_section("Object ", (void *)object, s->objsize);
dump_stack();
}
@@ -1447,7 +1421,7 @@
set_freepointer(s, last, NULL);
page->freelist = start;
- page->inuse = 0;
+ page->inuse = page->objects;
page->frozen = 1;
out:
return page;
@@ -1534,7 +1508,7 @@
struct page *page, int tail)
{
n->nr_partial++;
- if (tail)
+ if (tail == DEACTIVATE_TO_TAIL)
list_add_tail(&page->lru, &n->partial);
else
list_add(&page->lru, &n->partial);
@@ -1554,10 +1528,13 @@
* Lock slab, remove from the partial list and put the object into the
* per cpu freelist.
*
+ * Returns a list of objects or NULL if it fails.
+ *
* Must hold list_lock.
*/
-static inline int acquire_slab(struct kmem_cache *s,
- struct kmem_cache_node *n, struct page *page)
+static inline void *acquire_slab(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct page *page,
+ int mode)
{
void *freelist;
unsigned long counters;
@@ -1572,7 +1549,8 @@
freelist = page->freelist;
counters = page->counters;
new.counters = counters;
- new.inuse = page->objects;
+ if (mode)
+ new.inuse = page->objects;
VM_BUG_ON(new.frozen);
new.frozen = 1;
@@ -1583,32 +1561,19 @@
"lock and freeze"));
remove_partial(n, page);
-
- if (freelist) {
- /* Populate the per cpu freelist */
- this_cpu_write(s->cpu_slab->freelist, freelist);
- this_cpu_write(s->cpu_slab->page, page);
- this_cpu_write(s->cpu_slab->node, page_to_nid(page));
- return 1;
- } else {
- /*
- * Slab page came from the wrong list. No object to allocate
- * from. Put it onto the correct list and continue partial
- * scan.
- */
- printk(KERN_ERR "SLUB: %s : Page without available objects on"
- " partial list\n", s->name);
- return 0;
- }
+ return freelist;
}
+static int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
+
/*
* Try to allocate a partial slab from a specific node.
*/
-static struct page *get_partial_node(struct kmem_cache *s,
- struct kmem_cache_node *n)
+static void *get_partial_node(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct kmem_cache_cpu *c)
{
- struct page *page;
+ struct page *page, *page2;
+ void *object = NULL;
/*
* Racy check. If we mistakenly see no partial slabs then we
@@ -1620,26 +1585,43 @@
return NULL;
spin_lock(&n->list_lock);
- list_for_each_entry(page, &n->partial, lru)
- if (acquire_slab(s, n, page))
- goto out;
- page = NULL;
-out:
+ list_for_each_entry_safe(page, page2, &n->partial, lru) {
+ void *t = acquire_slab(s, n, page, object == NULL);
+ int available;
+
+ if (!t)
+ break;
+
+ if (!object) {
+ c->page = page;
+ c->node = page_to_nid(page);
+ stat(s, ALLOC_FROM_PARTIAL);
+ object = t;
+ available = page->objects - page->inuse;
+ } else {
+ page->freelist = t;
+ available = put_cpu_partial(s, page, 0);
+ }
+ if (kmem_cache_debug(s) || available > s->cpu_partial / 2)
+ break;
+
+ }
spin_unlock(&n->list_lock);
- return page;
+ return object;
}
/*
* Get a page from somewhere. Search in increasing NUMA distances.
*/
-static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
+static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags,
+ struct kmem_cache_cpu *c)
{
#ifdef CONFIG_NUMA
struct zonelist *zonelist;
struct zoneref *z;
struct zone *zone;
enum zone_type high_zoneidx = gfp_zone(flags);
- struct page *page;
+ void *object;
/*
* The defrag ratio allows a configuration of the tradeoffs between
@@ -1672,10 +1654,10 @@
if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
n->nr_partial > s->min_partial) {
- page = get_partial_node(s, n);
- if (page) {
+ object = get_partial_node(s, n, c);
+ if (object) {
put_mems_allowed();
- return page;
+ return object;
}
}
}
@@ -1687,16 +1669,17 @@
/*
* Get a partial page, lock it and return it.
*/
-static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node)
+static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
+ struct kmem_cache_cpu *c)
{
- struct page *page;
+ void *object;
int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
- page = get_partial_node(s, get_node(s, searchnode));
- if (page || node != NUMA_NO_NODE)
- return page;
+ object = get_partial_node(s, get_node(s, searchnode), c);
+ if (object || node != NUMA_NO_NODE)
+ return object;
- return get_any_partial(s, flags);
+ return get_any_partial(s, flags, c);
}
#ifdef CONFIG_PREEMPT
@@ -1765,9 +1748,6 @@
for_each_possible_cpu(cpu)
per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
}
-/*
- * Remove the cpu slab
- */
/*
* Remove the cpu slab
@@ -1781,13 +1761,13 @@
enum slab_modes l = M_NONE, m = M_NONE;
void *freelist;
void *nextfree;
- int tail = 0;
+ int tail = DEACTIVATE_TO_HEAD;
struct page new;
struct page old;
if (page->freelist) {
stat(s, DEACTIVATE_REMOTE_FREES);
- tail = 1;
+ tail = DEACTIVATE_TO_TAIL;
}
c->tid = next_tid(c->tid);
@@ -1893,7 +1873,7 @@
if (m == M_PARTIAL) {
add_partial(n, page, tail);
- stat(s, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
+ stat(s, tail);
} else if (m == M_FULL) {
@@ -1920,6 +1900,123 @@
}
}
+/* Unfreeze all the cpu partial slabs */
+static void unfreeze_partials(struct kmem_cache *s)
+{
+ struct kmem_cache_node *n = NULL;
+ struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);
+ struct page *page;
+
+ while ((page = c->partial)) {
+ enum slab_modes { M_PARTIAL, M_FREE };
+ enum slab_modes l, m;
+ struct page new;
+ struct page old;
+
+ c->partial = page->next;
+ l = M_FREE;
+
+ do {
+
+ old.freelist = page->freelist;
+ old.counters = page->counters;
+ VM_BUG_ON(!old.frozen);
+
+ new.counters = old.counters;
+ new.freelist = old.freelist;
+
+ new.frozen = 0;
+
+ if (!new.inuse && (!n || n->nr_partial > s->min_partial))
+ m = M_FREE;
+ else {
+ struct kmem_cache_node *n2 = get_node(s,
+ page_to_nid(page));
+
+ m = M_PARTIAL;
+ if (n != n2) {
+ if (n)
+ spin_unlock(&n->list_lock);
+
+ n = n2;
+ spin_lock(&n->list_lock);
+ }
+ }
+
+ if (l != m) {
+ if (l == M_PARTIAL)
+ remove_partial(n, page);
+ else
+ add_partial(n, page, 1);
+
+ l = m;
+ }
+
+ } while (!cmpxchg_double_slab(s, page,
+ old.freelist, old.counters,
+ new.freelist, new.counters,
+ "unfreezing slab"));
+
+ if (m == M_FREE) {
+ stat(s, DEACTIVATE_EMPTY);
+ discard_slab(s, page);
+ stat(s, FREE_SLAB);
+ }
+ }
+
+ if (n)
+ spin_unlock(&n->list_lock);
+}
+
+/*
+ * Put a page that was just frozen (in __slab_free) into a partial page
+ * slot if available. This is done without interrupts disabled and without
+ * preemption disabled. The cmpxchg is racy and may put the partial page
+ * onto a random cpus partial slot.
+ *
+ * If we did not find a slot then simply move all the partials to the
+ * per node partial list.
+ */
+int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
+{
+ struct page *oldpage;
+ int pages;
+ int pobjects;
+
+ do {
+ pages = 0;
+ pobjects = 0;
+ oldpage = this_cpu_read(s->cpu_slab->partial);
+
+ if (oldpage) {
+ pobjects = oldpage->pobjects;
+ pages = oldpage->pages;
+ if (drain && pobjects > s->cpu_partial) {
+ unsigned long flags;
+ /*
+ * partial array is full. Move the existing
+ * set to the per node partial list.
+ */
+ local_irq_save(flags);
+ unfreeze_partials(s);
+ local_irq_restore(flags);
+ pobjects = 0;
+ pages = 0;
+ }
+ }
+
+ pages++;
+ pobjects += page->objects - page->inuse;
+
+ page->pages = pages;
+ page->pobjects = pobjects;
+ page->next = oldpage;
+
+ } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
+ stat(s, CPU_PARTIAL_FREE);
+ return pobjects;
+}
+
static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
{
stat(s, CPUSLAB_FLUSH);
@@ -1935,8 +2032,12 @@
{
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
- if (likely(c && c->page))
- flush_slab(s, c);
+ if (likely(c)) {
+ if (c->page)
+ flush_slab(s, c);
+
+ unfreeze_partials(s);
+ }
}
static void flush_cpu_slab(void *d)
@@ -2027,12 +2128,39 @@
}
}
+static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
+ int node, struct kmem_cache_cpu **pc)
+{
+ void *object;
+ struct kmem_cache_cpu *c;
+ struct page *page = new_slab(s, flags, node);
+
+ if (page) {
+ c = __this_cpu_ptr(s->cpu_slab);
+ if (c->page)
+ flush_slab(s, c);
+
+ /*
+ * No other reference to the page yet so we can
+ * muck around with it freely without cmpxchg
+ */
+ object = page->freelist;
+ page->freelist = NULL;
+
+ stat(s, ALLOC_SLAB);
+ c->node = page_to_nid(page);
+ c->page = page;
+ *pc = c;
+ } else
+ object = NULL;
+
+ return object;
+}
+
/*
* Slow path. The lockless freelist is empty or we need to perform
* debugging duties.
*
- * Interrupts are disabled.
- *
* Processing is still very fast if new objects have been freed to the
* regular freelist. In that case we simply take over the regular freelist
* as the lockless freelist and zap the regular freelist.
@@ -2049,7 +2177,6 @@
unsigned long addr, struct kmem_cache_cpu *c)
{
void **object;
- struct page *page;
unsigned long flags;
struct page new;
unsigned long counters;
@@ -2064,13 +2191,9 @@
c = this_cpu_ptr(s->cpu_slab);
#endif
- /* We handle __GFP_ZERO in the caller */
- gfpflags &= ~__GFP_ZERO;
-
- page = c->page;
- if (!page)
+ if (!c->page)
goto new_slab;
-
+redo:
if (unlikely(!node_match(c, node))) {
stat(s, ALLOC_NODE_MISMATCH);
deactivate_slab(s, c);
@@ -2080,8 +2203,8 @@
stat(s, ALLOC_SLOWPATH);
do {
- object = page->freelist;
- counters = page->counters;
+ object = c->page->freelist;
+ counters = c->page->counters;
new.counters = counters;
VM_BUG_ON(!new.frozen);
@@ -2093,17 +2216,17 @@
*
* If there are objects left then we retrieve them
* and use them to refill the per cpu queue.
- */
+ */
- new.inuse = page->objects;
+ new.inuse = c->page->objects;
new.frozen = object != NULL;
- } while (!__cmpxchg_double_slab(s, page,
+ } while (!__cmpxchg_double_slab(s, c->page,
object, counters,
NULL, new.counters,
"__slab_alloc"));
- if (unlikely(!object)) {
+ if (!object) {
c->page = NULL;
stat(s, DEACTIVATE_BYPASS);
goto new_slab;
@@ -2112,58 +2235,47 @@
stat(s, ALLOC_REFILL);
load_freelist:
- VM_BUG_ON(!page->frozen);
c->freelist = get_freepointer(s, object);
c->tid = next_tid(c->tid);
local_irq_restore(flags);
return object;
new_slab:
- page = get_partial(s, gfpflags, node);
- if (page) {
- stat(s, ALLOC_FROM_PARTIAL);
- object = c->freelist;
- if (kmem_cache_debug(s))
- goto debug;
- goto load_freelist;
+ if (c->partial) {
+ c->page = c->partial;
+ c->partial = c->page->next;
+ c->node = page_to_nid(c->page);
+ stat(s, CPU_PARTIAL_ALLOC);
+ c->freelist = NULL;
+ goto redo;
}
- page = new_slab(s, gfpflags, node);
+ /* Then do expensive stuff like retrieving pages from the partial lists */
+ object = get_partial(s, gfpflags, node, c);
- if (page) {
- c = __this_cpu_ptr(s->cpu_slab);
- if (c->page)
- flush_slab(s, c);
+ if (unlikely(!object)) {
- /*
- * No other reference to the page yet so we can
- * muck around with it freely without cmpxchg
- */
- object = page->freelist;
- page->freelist = NULL;
- page->inuse = page->objects;
+ object = new_slab_objects(s, gfpflags, node, &c);
- stat(s, ALLOC_SLAB);
- c->node = page_to_nid(page);
- c->page = page;
+ if (unlikely(!object)) {
+ if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
+ slab_out_of_memory(s, gfpflags, node);
- if (kmem_cache_debug(s))
- goto debug;
- goto load_freelist;
+ local_irq_restore(flags);
+ return NULL;
+ }
}
- if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
- slab_out_of_memory(s, gfpflags, node);
- local_irq_restore(flags);
- return NULL;
-debug:
- if (!object || !alloc_debug_processing(s, page, object, addr))
- goto new_slab;
+ if (likely(!kmem_cache_debug(s)))
+ goto load_freelist;
+
+ /* Only entered in the debug case */
+ if (!alloc_debug_processing(s, c->page, object, addr))
+ goto new_slab; /* Slab failed checks. Next slab needed */
c->freelist = get_freepointer(s, object);
deactivate_slab(s, c);
- c->page = NULL;
c->node = NUMA_NO_NODE;
local_irq_restore(flags);
return object;
@@ -2333,16 +2445,29 @@
was_frozen = new.frozen;
new.inuse--;
if ((!new.inuse || !prior) && !was_frozen && !n) {
- n = get_node(s, page_to_nid(page));
- /*
- * Speculatively acquire the list_lock.
- * If the cmpxchg does not succeed then we may
- * drop the list_lock without any processing.
- *
- * Otherwise the list_lock will synchronize with
- * other processors updating the list of slabs.
- */
- spin_lock_irqsave(&n->list_lock, flags);
+
+ if (!kmem_cache_debug(s) && !prior)
+
+ /*
+ * Slab was on no list before and will be partially empty
+ * We can defer the list move and instead freeze it.
+ */
+ new.frozen = 1;
+
+ else { /* Needs to be taken off a list */
+
+ n = get_node(s, page_to_nid(page));
+ /*
+ * Speculatively acquire the list_lock.
+ * If the cmpxchg does not succeed then we may
+ * drop the list_lock without any processing.
+ *
+ * Otherwise the list_lock will synchronize with
+ * other processors updating the list of slabs.
+ */
+ spin_lock_irqsave(&n->list_lock, flags);
+
+ }
}
inuse = new.inuse;
@@ -2352,7 +2477,15 @@
"__slab_free"));
if (likely(!n)) {
- /*
+
+ /*
+ * If we just froze the page then put it onto the
+ * per cpu partial list.
+ */
+ if (new.frozen && !was_frozen)
+ put_cpu_partial(s, page, 1);
+
+ /*
* The list lock was not taken therefore no list
* activity can be necessary.
*/
@@ -2377,7 +2510,7 @@
*/
if (unlikely(!prior)) {
remove_full(s, page);
- add_partial(n, page, 1);
+ add_partial(n, page, DEACTIVATE_TO_TAIL);
stat(s, FREE_ADD_PARTIAL);
}
}
@@ -2421,7 +2554,6 @@
slab_free_hook(s, x);
redo:
-
/*
* Determine the currently cpus per cpu slab.
* The cpu may change afterward. However that does not matter since
@@ -2685,7 +2817,7 @@
n = page->freelist;
BUG_ON(!n);
page->freelist = get_freepointer(kmem_cache_node, n);
- page->inuse++;
+ page->inuse = 1;
page->frozen = 0;
kmem_cache_node->node[node] = n;
#ifdef CONFIG_SLUB_DEBUG
@@ -2695,7 +2827,7 @@
init_kmem_cache_node(n, kmem_cache_node);
inc_slabs_node(kmem_cache_node, node, page->objects);
- add_partial(n, page, 0);
+ add_partial(n, page, DEACTIVATE_TO_HEAD);
}
static void free_kmem_cache_nodes(struct kmem_cache *s)
@@ -2911,7 +3043,34 @@
* The larger the object size is, the more pages we want on the partial
* list to avoid pounding the page allocator excessively.
*/
- set_min_partial(s, ilog2(s->size));
+ set_min_partial(s, ilog2(s->size) / 2);
+
+ /*
+ * cpu_partial determined the maximum number of objects kept in the
+ * per cpu partial lists of a processor.
+ *
+ * Per cpu partial lists mainly contain slabs that just have one
+ * object freed. If they are used for allocation then they can be
+ * filled up again with minimal effort. The slab will never hit the
+ * per node partial lists and therefore no locking will be required.
+ *
+ * This setting also determines
+ *
+ * A) The number of objects from per cpu partial slabs dumped to the
+ * per node list when we reach the limit.
+ * B) The number of objects in cpu partial slabs to extract from the
+ * per node list when we run out of per cpu objects. We only fetch 50%
+ * to keep some capacity around for frees.
+ */
+ if (s->size >= PAGE_SIZE)
+ s->cpu_partial = 2;
+ else if (s->size >= 1024)
+ s->cpu_partial = 6;
+ else if (s->size >= 256)
+ s->cpu_partial = 13;
+ else
+ s->cpu_partial = 30;
+
s->refcount = 1;
#ifdef CONFIG_NUMA
s->remote_node_defrag_ratio = 1000;
@@ -2970,13 +3129,13 @@
/*
* Attempt to free all partial slabs on a node.
+ * This is called from kmem_cache_close(). We must be the last thread
+ * using the cache and therefore we do not need to lock anymore.
*/
static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
{
- unsigned long flags;
struct page *page, *h;
- spin_lock_irqsave(&n->list_lock, flags);
list_for_each_entry_safe(page, h, &n->partial, lru) {
if (!page->inuse) {
remove_partial(n, page);
@@ -2986,7 +3145,6 @@
"Objects remaining on kmem_cache_close()");
}
}
- spin_unlock_irqrestore(&n->list_lock, flags);
}
/*
@@ -3020,6 +3178,7 @@
s->refcount--;
if (!s->refcount) {
list_del(&s->list);
+ up_write(&slub_lock);
if (kmem_cache_close(s)) {
printk(KERN_ERR "SLUB %s: %s called for cache that "
"still has objects.\n", s->name, __func__);
@@ -3028,8 +3187,8 @@
if (s->flags & SLAB_DESTROY_BY_RCU)
rcu_barrier();
sysfs_slab_remove(s);
- }
- up_write(&slub_lock);
+ } else
+ up_write(&slub_lock);
}
EXPORT_SYMBOL(kmem_cache_destroy);
@@ -3347,23 +3506,23 @@
* list_lock. page->inuse here is the upper limit.
*/
list_for_each_entry_safe(page, t, &n->partial, lru) {
- if (!page->inuse) {
- remove_partial(n, page);
- discard_slab(s, page);
- } else {
- list_move(&page->lru,
- slabs_by_inuse + page->inuse);
- }
+ list_move(&page->lru, slabs_by_inuse + page->inuse);
+ if (!page->inuse)
+ n->nr_partial--;
}
/*
* Rebuild the partial list with the slabs filled up most
* first and the least used slabs at the end.
*/
- for (i = objects - 1; i >= 0; i--)
+ for (i = objects - 1; i > 0; i--)
list_splice(slabs_by_inuse + i, n->partial.prev);
spin_unlock_irqrestore(&n->list_lock, flags);
+
+ /* Release empty slabs */
+ list_for_each_entry_safe(page, t, slabs_by_inuse, lru)
+ discard_slab(s, page);
}
kfree(slabs_by_inuse);
@@ -4319,6 +4478,7 @@
for_each_possible_cpu(cpu) {
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
+ struct page *page;
if (!c || c->node < 0)
continue;
@@ -4334,6 +4494,13 @@
total += x;
nodes[c->node] += x;
}
+ page = c->partial;
+
+ if (page) {
+ x = page->pobjects;
+ total += x;
+ nodes[c->node] += x;
+ }
per_cpu[c->node]++;
}
}
@@ -4412,11 +4579,12 @@
};
#define SLAB_ATTR_RO(_name) \
- static struct slab_attribute _name##_attr = __ATTR_RO(_name)
+ static struct slab_attribute _name##_attr = \
+ __ATTR(_name, 0400, _name##_show, NULL)
#define SLAB_ATTR(_name) \
static struct slab_attribute _name##_attr = \
- __ATTR(_name, 0644, _name##_show, _name##_store)
+ __ATTR(_name, 0600, _name##_show, _name##_store)
static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
{
@@ -4485,6 +4653,27 @@
}
SLAB_ATTR(min_partial);
+static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
+{
+ return sprintf(buf, "%u\n", s->cpu_partial);
+}
+
+static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
+ size_t length)
+{
+ unsigned long objects;
+ int err;
+
+ err = strict_strtoul(buf, 10, &objects);
+ if (err)
+ return err;
+
+ s->cpu_partial = objects;
+ flush_all(s);
+ return length;
+}
+SLAB_ATTR(cpu_partial);
+
static ssize_t ctor_show(struct kmem_cache *s, char *buf)
{
if (!s->ctor)
@@ -4523,6 +4712,37 @@
}
SLAB_ATTR_RO(objects_partial);
+static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
+{
+ int objects = 0;
+ int pages = 0;
+ int cpu;
+ int len;
+
+ for_each_online_cpu(cpu) {
+ struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
+
+ if (page) {
+ pages += page->pages;
+ objects += page->pobjects;
+ }
+ }
+
+ len = sprintf(buf, "%d(%d)", objects, pages);
+
+#ifdef CONFIG_SMP
+ for_each_online_cpu(cpu) {
+ struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
+
+ if (page && len < PAGE_SIZE - 20)
+ len += sprintf(buf + len, " C%d=%d(%d)", cpu,
+ page->pobjects, page->pages);
+ }
+#endif
+ return len + sprintf(buf + len, "\n");
+}
+SLAB_ATTR_RO(slabs_cpu_partial);
+
static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
{
return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
@@ -4845,6 +5065,8 @@
STAT_ATTR(ORDER_FALLBACK, order_fallback);
STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
+STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
+STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
#endif
static struct attribute *slab_attrs[] = {
@@ -4853,6 +5075,7 @@
&objs_per_slab_attr.attr,
&order_attr.attr,
&min_partial_attr.attr,
+ &cpu_partial_attr.attr,
&objects_attr.attr,
&objects_partial_attr.attr,
&partial_attr.attr,
@@ -4865,6 +5088,7 @@
&destroy_by_rcu_attr.attr,
&shrink_attr.attr,
&reserved_attr.attr,
+ &slabs_cpu_partial_attr.attr,
#ifdef CONFIG_SLUB_DEBUG
&total_objects_attr.attr,
&slabs_attr.attr,
@@ -4906,6 +5130,8 @@
&order_fallback_attr.attr,
&cmpxchg_double_fail_attr.attr,
&cmpxchg_double_cpu_fail_attr.attr,
+ &cpu_partial_alloc_attr.attr,
+ &cpu_partial_free_attr.attr,
#endif
#ifdef CONFIG_FAILSLAB
&failslab_attr.attr,
@@ -5257,7 +5483,7 @@
static int __init slab_proc_init(void)
{
- proc_create("slabinfo", S_IRUGO, NULL, &proc_slabinfo_operations);
+ proc_create("slabinfo", S_IRUSR, NULL, &proc_slabinfo_operations);
return 0;
}
module_init(slab_proc_init);
diff --git a/tools/slub/slabinfo.c b/tools/slub/slabinfo.c
index 868cc93..164cbcf 100644
--- a/tools/slub/slabinfo.c
+++ b/tools/slub/slabinfo.c
@@ -42,6 +42,7 @@
unsigned long deactivate_remote_frees, order_fallback;
unsigned long cmpxchg_double_cpu_fail, cmpxchg_double_fail;
unsigned long alloc_node_mismatch, deactivate_bypass;
+ unsigned long cpu_partial_alloc, cpu_partial_free;
int numa[MAX_NODES];
int numa_partial[MAX_NODES];
} slabinfo[MAX_SLABS];
@@ -455,6 +456,11 @@
s->alloc_from_partial * 100 / total_alloc,
s->free_remove_partial * 100 / total_free);
+ printf("Cpu partial list %8lu %8lu %3lu %3lu\n",
+ s->cpu_partial_alloc, s->cpu_partial_free,
+ s->cpu_partial_alloc * 100 / total_alloc,
+ s->cpu_partial_free * 100 / total_free);
+
printf("RemoteObj/SlabFrozen %8lu %8lu %3lu %3lu\n",
s->deactivate_remote_frees, s->free_frozen,
s->deactivate_remote_frees * 100 / total_alloc,
@@ -1145,7 +1151,7 @@
switch (de->d_type) {
case DT_LNK:
alias->name = strdup(de->d_name);
- count = readlink(de->d_name, buffer, sizeof(buffer));
+ count = readlink(de->d_name, buffer, sizeof(buffer)-1);
if (count < 0)
fatal("Cannot read symlink %s\n", de->d_name);
@@ -1209,6 +1215,8 @@
slab->order_fallback = get_obj("order_fallback");
slab->cmpxchg_double_cpu_fail = get_obj("cmpxchg_double_cpu_fail");
slab->cmpxchg_double_fail = get_obj("cmpxchg_double_fail");
+ slab->cpu_partial_alloc = get_obj("cpu_partial_alloc");
+ slab->cpu_partial_free = get_obj("cpu_partial_free");
slab->alloc_node_mismatch = get_obj("alloc_node_mismatch");
slab->deactivate_bypass = get_obj("deactivate_bypass");
chdir("..");
