Root/mm/slab_common.c

1/*
2 * Slab allocator functions that are independent of the allocator strategy
3 *
4 * (C) 2012 Christoph Lameter <cl@linux.com>
5 */
6#include <linux/slab.h>
7
8#include <linux/mm.h>
9#include <linux/poison.h>
10#include <linux/interrupt.h>
11#include <linux/memory.h>
12#include <linux/compiler.h>
13#include <linux/module.h>
14#include <linux/cpu.h>
15#include <linux/uaccess.h>
16#include <linux/seq_file.h>
17#include <linux/proc_fs.h>
18#include <asm/cacheflush.h>
19#include <asm/tlbflush.h>
20#include <asm/page.h>
21#include <linux/memcontrol.h>
22#include <trace/events/kmem.h>
23
24#include "slab.h"
25
26enum slab_state slab_state;
27LIST_HEAD(slab_caches);
28DEFINE_MUTEX(slab_mutex);
29struct kmem_cache *kmem_cache;
30
31#ifdef CONFIG_DEBUG_VM
32static int kmem_cache_sanity_check(struct mem_cgroup *memcg, const char *name,
33                   size_t size)
34{
35    struct kmem_cache *s = NULL;
36
37    if (!name || in_interrupt() || size < sizeof(void *) ||
38        size > KMALLOC_MAX_SIZE) {
39        pr_err("kmem_cache_create(%s) integrity check failed\n", name);
40        return -EINVAL;
41    }
42
43    list_for_each_entry(s, &slab_caches, list) {
44        char tmp;
45        int res;
46
47        /*
48         * This happens when the module gets unloaded and doesn't
49         * destroy its slab cache and no-one else reuses the vmalloc
50         * area of the module. Print a warning.
51         */
52        res = probe_kernel_address(s->name, tmp);
53        if (res) {
54            pr_err("Slab cache with size %d has lost its name\n",
55                   s->object_size);
56            continue;
57        }
58
59#if !defined(CONFIG_SLUB) || !defined(CONFIG_SLUB_DEBUG_ON)
60        /*
61         * For simplicity, we won't check this in the list of memcg
62         * caches. We have control over memcg naming, and if there
63         * aren't duplicates in the global list, there won't be any
64         * duplicates in the memcg lists as well.
65         */
66        if (!memcg && !strcmp(s->name, name)) {
67            pr_err("%s (%s): Cache name already exists.\n",
68                   __func__, name);
69            dump_stack();
70            s = NULL;
71            return -EINVAL;
72        }
73#endif
74    }
75
76    WARN_ON(strchr(name, ' ')); /* It confuses parsers */
77    return 0;
78}
79#else
80static inline int kmem_cache_sanity_check(struct mem_cgroup *memcg,
81                      const char *name, size_t size)
82{
83    return 0;
84}
85#endif
86
87#ifdef CONFIG_MEMCG_KMEM
88int memcg_update_all_caches(int num_memcgs)
89{
90    struct kmem_cache *s;
91    int ret = 0;
92    mutex_lock(&slab_mutex);
93
94    list_for_each_entry(s, &slab_caches, list) {
95        if (!is_root_cache(s))
96            continue;
97
98        ret = memcg_update_cache_size(s, num_memcgs);
99        /*
100         * See comment in memcontrol.c, memcg_update_cache_size:
101         * Instead of freeing the memory, we'll just leave the caches
102         * up to this point in an updated state.
103         */
104        if (ret)
105            goto out;
106    }
107
108    memcg_update_array_size(num_memcgs);
109out:
110    mutex_unlock(&slab_mutex);
111    return ret;
112}
113#endif
114
115/*
116 * Figure out what the alignment of the objects will be given a set of
117 * flags, a user specified alignment and the size of the objects.
118 */
119unsigned long calculate_alignment(unsigned long flags,
120        unsigned long align, unsigned long size)
121{
122    /*
123     * If the user wants hardware cache aligned objects then follow that
124     * suggestion if the object is sufficiently large.
125     *
126     * The hardware cache alignment cannot override the specified
127     * alignment though. If that is greater then use it.
128     */
129    if (flags & SLAB_HWCACHE_ALIGN) {
130        unsigned long ralign = cache_line_size();
131        while (size <= ralign / 2)
132            ralign /= 2;
133        align = max(align, ralign);
134    }
135
136    if (align < ARCH_SLAB_MINALIGN)
137        align = ARCH_SLAB_MINALIGN;
138
139    return ALIGN(align, sizeof(void *));
140}
141
142
143/*
144 * kmem_cache_create - Create a cache.
145 * @name: A string which is used in /proc/slabinfo to identify this cache.
146 * @size: The size of objects to be created in this cache.
147 * @align: The required alignment for the objects.
148 * @flags: SLAB flags
149 * @ctor: A constructor for the objects.
150 *
151 * Returns a ptr to the cache on success, NULL on failure.
152 * Cannot be called within a interrupt, but can be interrupted.
153 * The @ctor is run when new pages are allocated by the cache.
154 *
155 * The flags are
156 *
157 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
158 * to catch references to uninitialised memory.
159 *
160 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
161 * for buffer overruns.
162 *
163 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
164 * cacheline. This can be beneficial if you're counting cycles as closely
165 * as davem.
166 */
167
168struct kmem_cache *
169kmem_cache_create_memcg(struct mem_cgroup *memcg, const char *name, size_t size,
170            size_t align, unsigned long flags, void (*ctor)(void *),
171            struct kmem_cache *parent_cache)
172{
173    struct kmem_cache *s = NULL;
174    int err = 0;
175
176    get_online_cpus();
177    mutex_lock(&slab_mutex);
178
179    if (!kmem_cache_sanity_check(memcg, name, size) == 0)
180        goto out_locked;
181
182    /*
183     * Some allocators will constraint the set of valid flags to a subset
184     * of all flags. We expect them to define CACHE_CREATE_MASK in this
185     * case, and we'll just provide them with a sanitized version of the
186     * passed flags.
187     */
188    flags &= CACHE_CREATE_MASK;
189
190    s = __kmem_cache_alias(memcg, name, size, align, flags, ctor);
191    if (s)
192        goto out_locked;
193
194    s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
195    if (s) {
196        s->object_size = s->size = size;
197        s->align = calculate_alignment(flags, align, size);
198        s->ctor = ctor;
199
200        if (memcg_register_cache(memcg, s, parent_cache)) {
201            kmem_cache_free(kmem_cache, s);
202            err = -ENOMEM;
203            goto out_locked;
204        }
205
206        s->name = kstrdup(name, GFP_KERNEL);
207        if (!s->name) {
208            kmem_cache_free(kmem_cache, s);
209            err = -ENOMEM;
210            goto out_locked;
211        }
212
213        err = __kmem_cache_create(s, flags);
214        if (!err) {
215            s->refcount = 1;
216            list_add(&s->list, &slab_caches);
217            memcg_cache_list_add(memcg, s);
218        } else {
219            kfree(s->name);
220            kmem_cache_free(kmem_cache, s);
221        }
222    } else
223        err = -ENOMEM;
224
225out_locked:
226    mutex_unlock(&slab_mutex);
227    put_online_cpus();
228
229    if (err) {
230
231        if (flags & SLAB_PANIC)
232            panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
233                name, err);
234        else {
235            printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d",
236                name, err);
237            dump_stack();
238        }
239
240        return NULL;
241    }
242
243    return s;
244}
245
246struct kmem_cache *
247kmem_cache_create(const char *name, size_t size, size_t align,
248          unsigned long flags, void (*ctor)(void *))
249{
250    return kmem_cache_create_memcg(NULL, name, size, align, flags, ctor, NULL);
251}
252EXPORT_SYMBOL(kmem_cache_create);
253
254void kmem_cache_destroy(struct kmem_cache *s)
255{
256    /* Destroy all the children caches if we aren't a memcg cache */
257    kmem_cache_destroy_memcg_children(s);
258
259    get_online_cpus();
260    mutex_lock(&slab_mutex);
261    s->refcount--;
262    if (!s->refcount) {
263        list_del(&s->list);
264
265        if (!__kmem_cache_shutdown(s)) {
266            mutex_unlock(&slab_mutex);
267            if (s->flags & SLAB_DESTROY_BY_RCU)
268                rcu_barrier();
269
270            memcg_release_cache(s);
271            kfree(s->name);
272            kmem_cache_free(kmem_cache, s);
273        } else {
274            list_add(&s->list, &slab_caches);
275            mutex_unlock(&slab_mutex);
276            printk(KERN_ERR "kmem_cache_destroy %s: Slab cache still has objects\n",
277                s->name);
278            dump_stack();
279        }
280    } else {
281        mutex_unlock(&slab_mutex);
282    }
283    put_online_cpus();
284}
285EXPORT_SYMBOL(kmem_cache_destroy);
286
287int slab_is_available(void)
288{
289    return slab_state >= UP;
290}
291
292#ifndef CONFIG_SLOB
293/* Create a cache during boot when no slab services are available yet */
294void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t size,
295        unsigned long flags)
296{
297    int err;
298
299    s->name = name;
300    s->size = s->object_size = size;
301    s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
302    err = __kmem_cache_create(s, flags);
303
304    if (err)
305        panic("Creation of kmalloc slab %s size=%zu failed. Reason %d\n",
306                    name, size, err);
307
308    s->refcount = -1; /* Exempt from merging for now */
309}
310
311struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size,
312                unsigned long flags)
313{
314    struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
315
316    if (!s)
317        panic("Out of memory when creating slab %s\n", name);
318
319    create_boot_cache(s, name, size, flags);
320    list_add(&s->list, &slab_caches);
321    s->refcount = 1;
322    return s;
323}
324
325struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
326EXPORT_SYMBOL(kmalloc_caches);
327
328#ifdef CONFIG_ZONE_DMA
329struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1];
330EXPORT_SYMBOL(kmalloc_dma_caches);
331#endif
332
333/*
334 * Conversion table for small slabs sizes / 8 to the index in the
335 * kmalloc array. This is necessary for slabs < 192 since we have non power
336 * of two cache sizes there. The size of larger slabs can be determined using
337 * fls.
338 */
339static s8 size_index[24] = {
340    3, /* 8 */
341    4, /* 16 */
342    5, /* 24 */
343    5, /* 32 */
344    6, /* 40 */
345    6, /* 48 */
346    6, /* 56 */
347    6, /* 64 */
348    1, /* 72 */
349    1, /* 80 */
350    1, /* 88 */
351    1, /* 96 */
352    7, /* 104 */
353    7, /* 112 */
354    7, /* 120 */
355    7, /* 128 */
356    2, /* 136 */
357    2, /* 144 */
358    2, /* 152 */
359    2, /* 160 */
360    2, /* 168 */
361    2, /* 176 */
362    2, /* 184 */
363    2 /* 192 */
364};
365
366static inline int size_index_elem(size_t bytes)
367{
368    return (bytes - 1) / 8;
369}
370
371/*
372 * Find the kmem_cache structure that serves a given size of
373 * allocation
374 */
375struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
376{
377    int index;
378
379    if (unlikely(size > KMALLOC_MAX_SIZE)) {
380        WARN_ON_ONCE(!(flags & __GFP_NOWARN));
381        return NULL;
382    }
383
384    if (size <= 192) {
385        if (!size)
386            return ZERO_SIZE_PTR;
387
388        index = size_index[size_index_elem(size)];
389    } else
390        index = fls(size - 1);
391
392#ifdef CONFIG_ZONE_DMA
393    if (unlikely((flags & GFP_DMA)))
394        return kmalloc_dma_caches[index];
395
396#endif
397    return kmalloc_caches[index];
398}
399
400/*
401 * Create the kmalloc array. Some of the regular kmalloc arrays
402 * may already have been created because they were needed to
403 * enable allocations for slab creation.
404 */
405void __init create_kmalloc_caches(unsigned long flags)
406{
407    int i;
408
409    /*
410     * Patch up the size_index table if we have strange large alignment
411     * requirements for the kmalloc array. This is only the case for
412     * MIPS it seems. The standard arches will not generate any code here.
413     *
414     * Largest permitted alignment is 256 bytes due to the way we
415     * handle the index determination for the smaller caches.
416     *
417     * Make sure that nothing crazy happens if someone starts tinkering
418     * around with ARCH_KMALLOC_MINALIGN
419     */
420    BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
421        (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
422
423    for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
424        int elem = size_index_elem(i);
425
426        if (elem >= ARRAY_SIZE(size_index))
427            break;
428        size_index[elem] = KMALLOC_SHIFT_LOW;
429    }
430
431    if (KMALLOC_MIN_SIZE >= 64) {
432        /*
433         * The 96 byte size cache is not used if the alignment
434         * is 64 byte.
435         */
436        for (i = 64 + 8; i <= 96; i += 8)
437            size_index[size_index_elem(i)] = 7;
438
439    }
440
441    if (KMALLOC_MIN_SIZE >= 128) {
442        /*
443         * The 192 byte sized cache is not used if the alignment
444         * is 128 byte. Redirect kmalloc to use the 256 byte cache
445         * instead.
446         */
447        for (i = 128 + 8; i <= 192; i += 8)
448            size_index[size_index_elem(i)] = 8;
449    }
450    for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
451        if (!kmalloc_caches[i]) {
452            kmalloc_caches[i] = create_kmalloc_cache(NULL,
453                            1 << i, flags);
454        }
455
456        /*
457         * Caches that are not of the two-to-the-power-of size.
458         * These have to be created immediately after the
459         * earlier power of two caches
460         */
461        if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6)
462            kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags);
463
464        if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7)
465            kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags);
466    }
467
468    /* Kmalloc array is now usable */
469    slab_state = UP;
470
471    for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
472        struct kmem_cache *s = kmalloc_caches[i];
473        char *n;
474
475        if (s) {
476            n = kasprintf(GFP_NOWAIT, "kmalloc-%d", kmalloc_size(i));
477
478            BUG_ON(!n);
479            s->name = n;
480        }
481    }
482
483#ifdef CONFIG_ZONE_DMA
484    for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
485        struct kmem_cache *s = kmalloc_caches[i];
486
487        if (s) {
488            int size = kmalloc_size(i);
489            char *n = kasprintf(GFP_NOWAIT,
490                 "dma-kmalloc-%d", size);
491
492            BUG_ON(!n);
493            kmalloc_dma_caches[i] = create_kmalloc_cache(n,
494                size, SLAB_CACHE_DMA | flags);
495        }
496    }
497#endif
498}
499#endif /* !CONFIG_SLOB */
500
501#ifdef CONFIG_TRACING
502void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
503{
504    void *ret = kmalloc_order(size, flags, order);
505    trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
506    return ret;
507}
508EXPORT_SYMBOL(kmalloc_order_trace);
509#endif
510
511#ifdef CONFIG_SLABINFO
512
513#ifdef CONFIG_SLAB
514#define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR)
515#else
516#define SLABINFO_RIGHTS S_IRUSR
517#endif
518
519void print_slabinfo_header(struct seq_file *m)
520{
521    /*
522     * Output format version, so at least we can change it
523     * without _too_ many complaints.
524     */
525#ifdef CONFIG_DEBUG_SLAB
526    seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
527#else
528    seq_puts(m, "slabinfo - version: 2.1\n");
529#endif
530    seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
531         "<objperslab> <pagesperslab>");
532    seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
533    seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
534#ifdef CONFIG_DEBUG_SLAB
535    seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
536         "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
537    seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
538#endif
539    seq_putc(m, '\n');
540}
541
542static void *s_start(struct seq_file *m, loff_t *pos)
543{
544    loff_t n = *pos;
545
546    mutex_lock(&slab_mutex);
547    if (!n)
548        print_slabinfo_header(m);
549
550    return seq_list_start(&slab_caches, *pos);
551}
552
553void *slab_next(struct seq_file *m, void *p, loff_t *pos)
554{
555    return seq_list_next(p, &slab_caches, pos);
556}
557
558void slab_stop(struct seq_file *m, void *p)
559{
560    mutex_unlock(&slab_mutex);
561}
562
563static void
564memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info)
565{
566    struct kmem_cache *c;
567    struct slabinfo sinfo;
568    int i;
569
570    if (!is_root_cache(s))
571        return;
572
573    for_each_memcg_cache_index(i) {
574        c = cache_from_memcg(s, i);
575        if (!c)
576            continue;
577
578        memset(&sinfo, 0, sizeof(sinfo));
579        get_slabinfo(c, &sinfo);
580
581        info->active_slabs += sinfo.active_slabs;
582        info->num_slabs += sinfo.num_slabs;
583        info->shared_avail += sinfo.shared_avail;
584        info->active_objs += sinfo.active_objs;
585        info->num_objs += sinfo.num_objs;
586    }
587}
588
589int cache_show(struct kmem_cache *s, struct seq_file *m)
590{
591    struct slabinfo sinfo;
592
593    memset(&sinfo, 0, sizeof(sinfo));
594    get_slabinfo(s, &sinfo);
595
596    memcg_accumulate_slabinfo(s, &sinfo);
597
598    seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
599           cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size,
600           sinfo.objects_per_slab, (1 << sinfo.cache_order));
601
602    seq_printf(m, " : tunables %4u %4u %4u",
603           sinfo.limit, sinfo.batchcount, sinfo.shared);
604    seq_printf(m, " : slabdata %6lu %6lu %6lu",
605           sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
606    slabinfo_show_stats(m, s);
607    seq_putc(m, '\n');
608    return 0;
609}
610
611static int s_show(struct seq_file *m, void *p)
612{
613    struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
614
615    if (!is_root_cache(s))
616        return 0;
617    return cache_show(s, m);
618}
619
620/*
621 * slabinfo_op - iterator that generates /proc/slabinfo
622 *
623 * Output layout:
624 * cache-name
625 * num-active-objs
626 * total-objs
627 * object size
628 * num-active-slabs
629 * total-slabs
630 * num-pages-per-slab
631 * + further values on SMP and with statistics enabled
632 */
633static const struct seq_operations slabinfo_op = {
634    .start = s_start,
635    .next = slab_next,
636    .stop = slab_stop,
637    .show = s_show,
638};
639
640static int slabinfo_open(struct inode *inode, struct file *file)
641{
642    return seq_open(file, &slabinfo_op);
643}
644
645static const struct file_operations proc_slabinfo_operations = {
646    .open = slabinfo_open,
647    .read = seq_read,
648    .write = slabinfo_write,
649    .llseek = seq_lseek,
650    .release = seq_release,
651};
652
653static int __init slab_proc_init(void)
654{
655    proc_create("slabinfo", SLABINFO_RIGHTS, NULL,
656                        &proc_slabinfo_operations);
657    return 0;
658}
659module_init(slab_proc_init);
660#endif /* CONFIG_SLABINFO */
661

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jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive