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a264df74df
Christian reported a warning like the following obtained during running
some KVM-related tests on s390:
WARNING: CPU: 8 PID: 208 at lib/percpu-refcount.c:108 percpu_ref_exit+0x50/0x58
Modules linked in: kvm(-) xt_CHECKSUM xt_MASQUERADE bonding xt_tcpudp ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 xt_conntrack ip6table_na>
CPU: 8 PID: 208 Comm: kworker/8:1 Not tainted 5.2.0+ #66
Hardware name: IBM 2964 NC9 712 (LPAR)
Workqueue: events sysfs_slab_remove_workfn
Krnl PSW : 0704e00180000000 0000001529746850 (percpu_ref_exit+0x50/0x58)
R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
Krnl GPRS: 00000000ffff8808 0000001529746740 000003f4e30e8e18 0036008100000000
0000001f00000000 0035008100000000 0000001fb3573ab8 0000000000000000
0000001fbdb6de00 0000000000000000 0000001529f01328 0000001fb3573b00
0000001fbb27e000 0000001fbdb69300 000003e009263d00 000003e009263cd0
Krnl Code: 0000001529746842: f0a0000407fe srp 4(11,%r0),2046,0
0000001529746848: 47000700 bc 0,1792
#000000152974684c: a7f40001 brc 15,152974684e
>0000001529746850: a7f4fff2 brc 15,1529746834
0000001529746854: 0707 bcr 0,%r7
0000001529746856: 0707 bcr 0,%r7
0000001529746858: eb8ff0580024 stmg %r8,%r15,88(%r15)
000000152974685e: a738ffff lhi %r3,-1
Call Trace:
([<000003e009263d00>] 0x3e009263d00)
[<00000015293252ea>] slab_kmem_cache_release+0x3a/0x70
[<0000001529b04882>] kobject_put+0xaa/0xe8
[<000000152918cf28>] process_one_work+0x1e8/0x428
[<000000152918d1b0>] worker_thread+0x48/0x460
[<00000015291942c6>] kthread+0x126/0x160
[<0000001529b22344>] ret_from_fork+0x28/0x30
[<0000001529b2234c>] kernel_thread_starter+0x0/0x10
Last Breaking-Event-Address:
[<000000152974684c>] percpu_ref_exit+0x4c/0x58
---[ end trace b035e7da5788eb09 ]---
The problem occurs because kmem_cache_destroy() is called immediately
after deleting of a memcg, so it races with the memcg kmem_cache
deactivation.
flush_memcg_workqueue() at the beginning of kmem_cache_destroy() is
supposed to guarantee that all deactivation processes are finished, but
failed to do so. It waits for an rcu grace period, after which all
children kmem_caches should be deactivated. During the deactivation
percpu_ref_kill() is called for non root kmem_cache refcounters, but it
requires yet another rcu grace period to finish the transition to the
atomic (dead) state.
So in a rare case when not all children kmem_caches are destroyed at the
moment when the root kmem_cache is about to be gone, we need to wait
another rcu grace period before destroying the root kmem_cache.
This issue can be triggered only with dynamically created kmem_caches
which are used with memcg accounting. In this case per-memcg child
kmem_caches are created. They are deactivated from the cgroup removing
path. If the destruction of the root kmem_cache is racing with the
removal of the cgroup (both are quite complicated multi-stage
processes), the described issue can occur. The only known way to
trigger it in the real life, is to unload some kernel module which
creates a dedicated kmem_cache, used from different memory cgroups with
GFP_ACCOUNT flag. If the unloading happens immediately after calling
rmdir on the corresponding cgroup, there is some chance to trigger the
issue.
Link: http://lkml.kernel.org/r/20191129025011.3076017-1-guro@fb.com
Fixes: f0a3a24b53
("mm: memcg/slab: rework non-root kmem_cache lifecycle management")
Signed-off-by: Roman Gushchin <guro@fb.com>
Reported-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1815 lines
45 KiB
C
1815 lines
45 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Slab allocator functions that are independent of the allocator strategy
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*
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* (C) 2012 Christoph Lameter <cl@linux.com>
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*/
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/poison.h>
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#include <linux/interrupt.h>
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#include <linux/memory.h>
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#include <linux/cache.h>
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#include <linux/compiler.h>
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#include <linux/module.h>
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#include <linux/cpu.h>
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#include <linux/uaccess.h>
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include <linux/debugfs.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#include <asm/page.h>
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#include <linux/memcontrol.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/kmem.h>
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#include "slab.h"
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enum slab_state slab_state;
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LIST_HEAD(slab_caches);
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DEFINE_MUTEX(slab_mutex);
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struct kmem_cache *kmem_cache;
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#ifdef CONFIG_HARDENED_USERCOPY
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bool usercopy_fallback __ro_after_init =
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IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK);
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module_param(usercopy_fallback, bool, 0400);
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MODULE_PARM_DESC(usercopy_fallback,
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"WARN instead of reject usercopy whitelist violations");
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#endif
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static LIST_HEAD(slab_caches_to_rcu_destroy);
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static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
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static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
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slab_caches_to_rcu_destroy_workfn);
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/*
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* Set of flags that will prevent slab merging
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*/
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#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
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SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
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SLAB_FAILSLAB | SLAB_KASAN)
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#define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
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SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
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/*
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* Merge control. If this is set then no merging of slab caches will occur.
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*/
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static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
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static int __init setup_slab_nomerge(char *str)
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{
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slab_nomerge = true;
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return 1;
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}
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#ifdef CONFIG_SLUB
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__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
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#endif
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__setup("slab_nomerge", setup_slab_nomerge);
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/*
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* Determine the size of a slab object
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*/
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unsigned int kmem_cache_size(struct kmem_cache *s)
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{
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return s->object_size;
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}
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EXPORT_SYMBOL(kmem_cache_size);
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#ifdef CONFIG_DEBUG_VM
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static int kmem_cache_sanity_check(const char *name, unsigned int size)
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{
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if (!name || in_interrupt() || size < sizeof(void *) ||
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size > KMALLOC_MAX_SIZE) {
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pr_err("kmem_cache_create(%s) integrity check failed\n", name);
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return -EINVAL;
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}
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WARN_ON(strchr(name, ' ')); /* It confuses parsers */
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return 0;
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}
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#else
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static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
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{
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return 0;
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}
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#endif
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void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p)
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{
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size_t i;
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for (i = 0; i < nr; i++) {
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if (s)
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kmem_cache_free(s, p[i]);
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else
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kfree(p[i]);
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}
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}
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int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
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void **p)
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{
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size_t i;
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for (i = 0; i < nr; i++) {
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void *x = p[i] = kmem_cache_alloc(s, flags);
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if (!x) {
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__kmem_cache_free_bulk(s, i, p);
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return 0;
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}
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}
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return i;
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}
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#ifdef CONFIG_MEMCG_KMEM
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LIST_HEAD(slab_root_caches);
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static DEFINE_SPINLOCK(memcg_kmem_wq_lock);
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static void kmemcg_cache_shutdown(struct percpu_ref *percpu_ref);
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void slab_init_memcg_params(struct kmem_cache *s)
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{
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s->memcg_params.root_cache = NULL;
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RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL);
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INIT_LIST_HEAD(&s->memcg_params.children);
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s->memcg_params.dying = false;
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}
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static int init_memcg_params(struct kmem_cache *s,
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struct kmem_cache *root_cache)
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{
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struct memcg_cache_array *arr;
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if (root_cache) {
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int ret = percpu_ref_init(&s->memcg_params.refcnt,
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kmemcg_cache_shutdown,
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0, GFP_KERNEL);
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if (ret)
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return ret;
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s->memcg_params.root_cache = root_cache;
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INIT_LIST_HEAD(&s->memcg_params.children_node);
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INIT_LIST_HEAD(&s->memcg_params.kmem_caches_node);
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return 0;
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}
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slab_init_memcg_params(s);
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if (!memcg_nr_cache_ids)
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return 0;
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arr = kvzalloc(sizeof(struct memcg_cache_array) +
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memcg_nr_cache_ids * sizeof(void *),
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GFP_KERNEL);
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if (!arr)
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return -ENOMEM;
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RCU_INIT_POINTER(s->memcg_params.memcg_caches, arr);
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return 0;
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}
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static void destroy_memcg_params(struct kmem_cache *s)
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{
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if (is_root_cache(s)) {
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kvfree(rcu_access_pointer(s->memcg_params.memcg_caches));
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} else {
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mem_cgroup_put(s->memcg_params.memcg);
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WRITE_ONCE(s->memcg_params.memcg, NULL);
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percpu_ref_exit(&s->memcg_params.refcnt);
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}
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}
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static void free_memcg_params(struct rcu_head *rcu)
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{
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struct memcg_cache_array *old;
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old = container_of(rcu, struct memcg_cache_array, rcu);
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kvfree(old);
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}
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static int update_memcg_params(struct kmem_cache *s, int new_array_size)
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{
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struct memcg_cache_array *old, *new;
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new = kvzalloc(sizeof(struct memcg_cache_array) +
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new_array_size * sizeof(void *), GFP_KERNEL);
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if (!new)
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return -ENOMEM;
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old = rcu_dereference_protected(s->memcg_params.memcg_caches,
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lockdep_is_held(&slab_mutex));
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if (old)
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memcpy(new->entries, old->entries,
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memcg_nr_cache_ids * sizeof(void *));
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rcu_assign_pointer(s->memcg_params.memcg_caches, new);
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if (old)
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call_rcu(&old->rcu, free_memcg_params);
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return 0;
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}
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int memcg_update_all_caches(int num_memcgs)
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{
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struct kmem_cache *s;
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int ret = 0;
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mutex_lock(&slab_mutex);
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list_for_each_entry(s, &slab_root_caches, root_caches_node) {
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ret = update_memcg_params(s, num_memcgs);
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/*
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* Instead of freeing the memory, we'll just leave the caches
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* up to this point in an updated state.
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*/
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if (ret)
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break;
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}
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mutex_unlock(&slab_mutex);
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return ret;
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}
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void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg)
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{
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if (is_root_cache(s)) {
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list_add(&s->root_caches_node, &slab_root_caches);
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} else {
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css_get(&memcg->css);
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s->memcg_params.memcg = memcg;
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list_add(&s->memcg_params.children_node,
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&s->memcg_params.root_cache->memcg_params.children);
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list_add(&s->memcg_params.kmem_caches_node,
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&s->memcg_params.memcg->kmem_caches);
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}
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}
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static void memcg_unlink_cache(struct kmem_cache *s)
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{
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if (is_root_cache(s)) {
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list_del(&s->root_caches_node);
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} else {
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list_del(&s->memcg_params.children_node);
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list_del(&s->memcg_params.kmem_caches_node);
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}
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}
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#else
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static inline int init_memcg_params(struct kmem_cache *s,
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struct kmem_cache *root_cache)
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{
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return 0;
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}
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static inline void destroy_memcg_params(struct kmem_cache *s)
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{
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}
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static inline void memcg_unlink_cache(struct kmem_cache *s)
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{
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}
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#endif /* CONFIG_MEMCG_KMEM */
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/*
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* Figure out what the alignment of the objects will be given a set of
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* flags, a user specified alignment and the size of the objects.
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*/
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static unsigned int calculate_alignment(slab_flags_t flags,
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unsigned int align, unsigned int size)
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{
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/*
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* If the user wants hardware cache aligned objects then follow that
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* suggestion if the object is sufficiently large.
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*
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* The hardware cache alignment cannot override the specified
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* alignment though. If that is greater then use it.
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*/
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if (flags & SLAB_HWCACHE_ALIGN) {
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unsigned int ralign;
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ralign = cache_line_size();
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while (size <= ralign / 2)
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ralign /= 2;
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align = max(align, ralign);
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}
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if (align < ARCH_SLAB_MINALIGN)
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align = ARCH_SLAB_MINALIGN;
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return ALIGN(align, sizeof(void *));
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}
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/*
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* Find a mergeable slab cache
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*/
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int slab_unmergeable(struct kmem_cache *s)
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{
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if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
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return 1;
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if (!is_root_cache(s))
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return 1;
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if (s->ctor)
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return 1;
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if (s->usersize)
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return 1;
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/*
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* We may have set a slab to be unmergeable during bootstrap.
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*/
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if (s->refcount < 0)
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return 1;
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return 0;
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}
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struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
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slab_flags_t flags, const char *name, void (*ctor)(void *))
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{
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struct kmem_cache *s;
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if (slab_nomerge)
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return NULL;
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if (ctor)
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return NULL;
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size = ALIGN(size, sizeof(void *));
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align = calculate_alignment(flags, align, size);
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size = ALIGN(size, align);
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flags = kmem_cache_flags(size, flags, name, NULL);
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if (flags & SLAB_NEVER_MERGE)
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return NULL;
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list_for_each_entry_reverse(s, &slab_root_caches, root_caches_node) {
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if (slab_unmergeable(s))
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continue;
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if (size > s->size)
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continue;
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if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
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continue;
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/*
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* Check if alignment is compatible.
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* Courtesy of Adrian Drzewiecki
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*/
|
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if ((s->size & ~(align - 1)) != s->size)
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continue;
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|
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if (s->size - size >= sizeof(void *))
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continue;
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if (IS_ENABLED(CONFIG_SLAB) && align &&
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(align > s->align || s->align % align))
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continue;
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return s;
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}
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return NULL;
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}
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|
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static struct kmem_cache *create_cache(const char *name,
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unsigned int object_size, unsigned int align,
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slab_flags_t flags, unsigned int useroffset,
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unsigned int usersize, void (*ctor)(void *),
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struct mem_cgroup *memcg, struct kmem_cache *root_cache)
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{
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struct kmem_cache *s;
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int err;
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if (WARN_ON(useroffset + usersize > object_size))
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useroffset = usersize = 0;
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err = -ENOMEM;
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s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
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if (!s)
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goto out;
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s->name = name;
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s->size = s->object_size = object_size;
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s->align = align;
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s->ctor = ctor;
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s->useroffset = useroffset;
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s->usersize = usersize;
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err = init_memcg_params(s, root_cache);
|
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if (err)
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goto out_free_cache;
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|
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err = __kmem_cache_create(s, flags);
|
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if (err)
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goto out_free_cache;
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|
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s->refcount = 1;
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list_add(&s->list, &slab_caches);
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memcg_link_cache(s, memcg);
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out:
|
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if (err)
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return ERR_PTR(err);
|
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return s;
|
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|
|
out_free_cache:
|
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destroy_memcg_params(s);
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kmem_cache_free(kmem_cache, s);
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goto out;
|
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}
|
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|
|
/**
|
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* kmem_cache_create_usercopy - Create a cache with a region suitable
|
|
* for copying to userspace
|
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* @name: A string which is used in /proc/slabinfo to identify this cache.
|
|
* @size: The size of objects to be created in this cache.
|
|
* @align: The required alignment for the objects.
|
|
* @flags: SLAB flags
|
|
* @useroffset: Usercopy region offset
|
|
* @usersize: Usercopy region size
|
|
* @ctor: A constructor for the objects.
|
|
*
|
|
* Cannot be called within a interrupt, but can be interrupted.
|
|
* The @ctor is run when new pages are allocated by the cache.
|
|
*
|
|
* The flags are
|
|
*
|
|
* %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
|
|
* to catch references to uninitialised memory.
|
|
*
|
|
* %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
|
|
* for buffer overruns.
|
|
*
|
|
* %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
|
|
* cacheline. This can be beneficial if you're counting cycles as closely
|
|
* as davem.
|
|
*
|
|
* Return: a pointer to the cache on success, NULL on failure.
|
|
*/
|
|
struct kmem_cache *
|
|
kmem_cache_create_usercopy(const char *name,
|
|
unsigned int size, unsigned int align,
|
|
slab_flags_t flags,
|
|
unsigned int useroffset, unsigned int usersize,
|
|
void (*ctor)(void *))
|
|
{
|
|
struct kmem_cache *s = NULL;
|
|
const char *cache_name;
|
|
int err;
|
|
|
|
get_online_cpus();
|
|
get_online_mems();
|
|
memcg_get_cache_ids();
|
|
|
|
mutex_lock(&slab_mutex);
|
|
|
|
err = kmem_cache_sanity_check(name, size);
|
|
if (err) {
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* Refuse requests with allocator specific flags */
|
|
if (flags & ~SLAB_FLAGS_PERMITTED) {
|
|
err = -EINVAL;
|
|
goto out_unlock;
|
|
}
|
|
|
|
/*
|
|
* Some allocators will constraint the set of valid flags to a subset
|
|
* of all flags. We expect them to define CACHE_CREATE_MASK in this
|
|
* case, and we'll just provide them with a sanitized version of the
|
|
* passed flags.
|
|
*/
|
|
flags &= CACHE_CREATE_MASK;
|
|
|
|
/* Fail closed on bad usersize of useroffset values. */
|
|
if (WARN_ON(!usersize && useroffset) ||
|
|
WARN_ON(size < usersize || size - usersize < useroffset))
|
|
usersize = useroffset = 0;
|
|
|
|
if (!usersize)
|
|
s = __kmem_cache_alias(name, size, align, flags, ctor);
|
|
if (s)
|
|
goto out_unlock;
|
|
|
|
cache_name = kstrdup_const(name, GFP_KERNEL);
|
|
if (!cache_name) {
|
|
err = -ENOMEM;
|
|
goto out_unlock;
|
|
}
|
|
|
|
s = create_cache(cache_name, size,
|
|
calculate_alignment(flags, align, size),
|
|
flags, useroffset, usersize, ctor, NULL, NULL);
|
|
if (IS_ERR(s)) {
|
|
err = PTR_ERR(s);
|
|
kfree_const(cache_name);
|
|
}
|
|
|
|
out_unlock:
|
|
mutex_unlock(&slab_mutex);
|
|
|
|
memcg_put_cache_ids();
|
|
put_online_mems();
|
|
put_online_cpus();
|
|
|
|
if (err) {
|
|
if (flags & SLAB_PANIC)
|
|
panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
|
|
name, err);
|
|
else {
|
|
pr_warn("kmem_cache_create(%s) failed with error %d\n",
|
|
name, err);
|
|
dump_stack();
|
|
}
|
|
return NULL;
|
|
}
|
|
return s;
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_create_usercopy);
|
|
|
|
/**
|
|
* kmem_cache_create - Create a cache.
|
|
* @name: A string which is used in /proc/slabinfo to identify this cache.
|
|
* @size: The size of objects to be created in this cache.
|
|
* @align: The required alignment for the objects.
|
|
* @flags: SLAB flags
|
|
* @ctor: A constructor for the objects.
|
|
*
|
|
* Cannot be called within a interrupt, but can be interrupted.
|
|
* The @ctor is run when new pages are allocated by the cache.
|
|
*
|
|
* The flags are
|
|
*
|
|
* %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
|
|
* to catch references to uninitialised memory.
|
|
*
|
|
* %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
|
|
* for buffer overruns.
|
|
*
|
|
* %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
|
|
* cacheline. This can be beneficial if you're counting cycles as closely
|
|
* as davem.
|
|
*
|
|
* Return: a pointer to the cache on success, NULL on failure.
|
|
*/
|
|
struct kmem_cache *
|
|
kmem_cache_create(const char *name, unsigned int size, unsigned int align,
|
|
slab_flags_t flags, void (*ctor)(void *))
|
|
{
|
|
return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
|
|
ctor);
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_create);
|
|
|
|
static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
|
|
{
|
|
LIST_HEAD(to_destroy);
|
|
struct kmem_cache *s, *s2;
|
|
|
|
/*
|
|
* On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
|
|
* @slab_caches_to_rcu_destroy list. The slab pages are freed
|
|
* through RCU and and the associated kmem_cache are dereferenced
|
|
* while freeing the pages, so the kmem_caches should be freed only
|
|
* after the pending RCU operations are finished. As rcu_barrier()
|
|
* is a pretty slow operation, we batch all pending destructions
|
|
* asynchronously.
|
|
*/
|
|
mutex_lock(&slab_mutex);
|
|
list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
|
|
mutex_unlock(&slab_mutex);
|
|
|
|
if (list_empty(&to_destroy))
|
|
return;
|
|
|
|
rcu_barrier();
|
|
|
|
list_for_each_entry_safe(s, s2, &to_destroy, list) {
|
|
#ifdef SLAB_SUPPORTS_SYSFS
|
|
sysfs_slab_release(s);
|
|
#else
|
|
slab_kmem_cache_release(s);
|
|
#endif
|
|
}
|
|
}
|
|
|
|
static int shutdown_cache(struct kmem_cache *s)
|
|
{
|
|
/* free asan quarantined objects */
|
|
kasan_cache_shutdown(s);
|
|
|
|
if (__kmem_cache_shutdown(s) != 0)
|
|
return -EBUSY;
|
|
|
|
memcg_unlink_cache(s);
|
|
list_del(&s->list);
|
|
|
|
if (s->flags & SLAB_TYPESAFE_BY_RCU) {
|
|
#ifdef SLAB_SUPPORTS_SYSFS
|
|
sysfs_slab_unlink(s);
|
|
#endif
|
|
list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
|
|
schedule_work(&slab_caches_to_rcu_destroy_work);
|
|
} else {
|
|
#ifdef SLAB_SUPPORTS_SYSFS
|
|
sysfs_slab_unlink(s);
|
|
sysfs_slab_release(s);
|
|
#else
|
|
slab_kmem_cache_release(s);
|
|
#endif
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
#ifdef CONFIG_MEMCG_KMEM
|
|
/*
|
|
* memcg_create_kmem_cache - Create a cache for a memory cgroup.
|
|
* @memcg: The memory cgroup the new cache is for.
|
|
* @root_cache: The parent of the new cache.
|
|
*
|
|
* This function attempts to create a kmem cache that will serve allocation
|
|
* requests going from @memcg to @root_cache. The new cache inherits properties
|
|
* from its parent.
|
|
*/
|
|
void memcg_create_kmem_cache(struct mem_cgroup *memcg,
|
|
struct kmem_cache *root_cache)
|
|
{
|
|
static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */
|
|
struct cgroup_subsys_state *css = &memcg->css;
|
|
struct memcg_cache_array *arr;
|
|
struct kmem_cache *s = NULL;
|
|
char *cache_name;
|
|
int idx;
|
|
|
|
get_online_cpus();
|
|
get_online_mems();
|
|
|
|
mutex_lock(&slab_mutex);
|
|
|
|
/*
|
|
* The memory cgroup could have been offlined while the cache
|
|
* creation work was pending.
|
|
*/
|
|
if (memcg->kmem_state != KMEM_ONLINE)
|
|
goto out_unlock;
|
|
|
|
idx = memcg_cache_id(memcg);
|
|
arr = rcu_dereference_protected(root_cache->memcg_params.memcg_caches,
|
|
lockdep_is_held(&slab_mutex));
|
|
|
|
/*
|
|
* Since per-memcg caches are created asynchronously on first
|
|
* allocation (see memcg_kmem_get_cache()), several threads can try to
|
|
* create the same cache, but only one of them may succeed.
|
|
*/
|
|
if (arr->entries[idx])
|
|
goto out_unlock;
|
|
|
|
cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf));
|
|
cache_name = kasprintf(GFP_KERNEL, "%s(%llu:%s)", root_cache->name,
|
|
css->serial_nr, memcg_name_buf);
|
|
if (!cache_name)
|
|
goto out_unlock;
|
|
|
|
s = create_cache(cache_name, root_cache->object_size,
|
|
root_cache->align,
|
|
root_cache->flags & CACHE_CREATE_MASK,
|
|
root_cache->useroffset, root_cache->usersize,
|
|
root_cache->ctor, memcg, root_cache);
|
|
/*
|
|
* If we could not create a memcg cache, do not complain, because
|
|
* that's not critical at all as we can always proceed with the root
|
|
* cache.
|
|
*/
|
|
if (IS_ERR(s)) {
|
|
kfree(cache_name);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/*
|
|
* Since readers won't lock (see memcg_kmem_get_cache()), we need a
|
|
* barrier here to ensure nobody will see the kmem_cache partially
|
|
* initialized.
|
|
*/
|
|
smp_wmb();
|
|
arr->entries[idx] = s;
|
|
|
|
out_unlock:
|
|
mutex_unlock(&slab_mutex);
|
|
|
|
put_online_mems();
|
|
put_online_cpus();
|
|
}
|
|
|
|
static void kmemcg_workfn(struct work_struct *work)
|
|
{
|
|
struct kmem_cache *s = container_of(work, struct kmem_cache,
|
|
memcg_params.work);
|
|
|
|
get_online_cpus();
|
|
get_online_mems();
|
|
|
|
mutex_lock(&slab_mutex);
|
|
s->memcg_params.work_fn(s);
|
|
mutex_unlock(&slab_mutex);
|
|
|
|
put_online_mems();
|
|
put_online_cpus();
|
|
}
|
|
|
|
static void kmemcg_rcufn(struct rcu_head *head)
|
|
{
|
|
struct kmem_cache *s = container_of(head, struct kmem_cache,
|
|
memcg_params.rcu_head);
|
|
|
|
/*
|
|
* We need to grab blocking locks. Bounce to ->work. The
|
|
* work item shares the space with the RCU head and can't be
|
|
* initialized eariler.
|
|
*/
|
|
INIT_WORK(&s->memcg_params.work, kmemcg_workfn);
|
|
queue_work(memcg_kmem_cache_wq, &s->memcg_params.work);
|
|
}
|
|
|
|
static void kmemcg_cache_shutdown_fn(struct kmem_cache *s)
|
|
{
|
|
WARN_ON(shutdown_cache(s));
|
|
}
|
|
|
|
static void kmemcg_cache_shutdown(struct percpu_ref *percpu_ref)
|
|
{
|
|
struct kmem_cache *s = container_of(percpu_ref, struct kmem_cache,
|
|
memcg_params.refcnt);
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&memcg_kmem_wq_lock, flags);
|
|
if (s->memcg_params.root_cache->memcg_params.dying)
|
|
goto unlock;
|
|
|
|
s->memcg_params.work_fn = kmemcg_cache_shutdown_fn;
|
|
INIT_WORK(&s->memcg_params.work, kmemcg_workfn);
|
|
queue_work(memcg_kmem_cache_wq, &s->memcg_params.work);
|
|
|
|
unlock:
|
|
spin_unlock_irqrestore(&memcg_kmem_wq_lock, flags);
|
|
}
|
|
|
|
static void kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s)
|
|
{
|
|
__kmemcg_cache_deactivate_after_rcu(s);
|
|
percpu_ref_kill(&s->memcg_params.refcnt);
|
|
}
|
|
|
|
static void kmemcg_cache_deactivate(struct kmem_cache *s)
|
|
{
|
|
if (WARN_ON_ONCE(is_root_cache(s)))
|
|
return;
|
|
|
|
__kmemcg_cache_deactivate(s);
|
|
s->flags |= SLAB_DEACTIVATED;
|
|
|
|
/*
|
|
* memcg_kmem_wq_lock is used to synchronize memcg_params.dying
|
|
* flag and make sure that no new kmem_cache deactivation tasks
|
|
* are queued (see flush_memcg_workqueue() ).
|
|
*/
|
|
spin_lock_irq(&memcg_kmem_wq_lock);
|
|
if (s->memcg_params.root_cache->memcg_params.dying)
|
|
goto unlock;
|
|
|
|
s->memcg_params.work_fn = kmemcg_cache_deactivate_after_rcu;
|
|
call_rcu(&s->memcg_params.rcu_head, kmemcg_rcufn);
|
|
unlock:
|
|
spin_unlock_irq(&memcg_kmem_wq_lock);
|
|
}
|
|
|
|
void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg,
|
|
struct mem_cgroup *parent)
|
|
{
|
|
int idx;
|
|
struct memcg_cache_array *arr;
|
|
struct kmem_cache *s, *c;
|
|
unsigned int nr_reparented;
|
|
|
|
idx = memcg_cache_id(memcg);
|
|
|
|
get_online_cpus();
|
|
get_online_mems();
|
|
|
|
mutex_lock(&slab_mutex);
|
|
list_for_each_entry(s, &slab_root_caches, root_caches_node) {
|
|
arr = rcu_dereference_protected(s->memcg_params.memcg_caches,
|
|
lockdep_is_held(&slab_mutex));
|
|
c = arr->entries[idx];
|
|
if (!c)
|
|
continue;
|
|
|
|
kmemcg_cache_deactivate(c);
|
|
arr->entries[idx] = NULL;
|
|
}
|
|
nr_reparented = 0;
|
|
list_for_each_entry(s, &memcg->kmem_caches,
|
|
memcg_params.kmem_caches_node) {
|
|
WRITE_ONCE(s->memcg_params.memcg, parent);
|
|
css_put(&memcg->css);
|
|
nr_reparented++;
|
|
}
|
|
if (nr_reparented) {
|
|
list_splice_init(&memcg->kmem_caches,
|
|
&parent->kmem_caches);
|
|
css_get_many(&parent->css, nr_reparented);
|
|
}
|
|
mutex_unlock(&slab_mutex);
|
|
|
|
put_online_mems();
|
|
put_online_cpus();
|
|
}
|
|
|
|
static int shutdown_memcg_caches(struct kmem_cache *s)
|
|
{
|
|
struct memcg_cache_array *arr;
|
|
struct kmem_cache *c, *c2;
|
|
LIST_HEAD(busy);
|
|
int i;
|
|
|
|
BUG_ON(!is_root_cache(s));
|
|
|
|
/*
|
|
* First, shutdown active caches, i.e. caches that belong to online
|
|
* memory cgroups.
|
|
*/
|
|
arr = rcu_dereference_protected(s->memcg_params.memcg_caches,
|
|
lockdep_is_held(&slab_mutex));
|
|
for_each_memcg_cache_index(i) {
|
|
c = arr->entries[i];
|
|
if (!c)
|
|
continue;
|
|
if (shutdown_cache(c))
|
|
/*
|
|
* The cache still has objects. Move it to a temporary
|
|
* list so as not to try to destroy it for a second
|
|
* time while iterating over inactive caches below.
|
|
*/
|
|
list_move(&c->memcg_params.children_node, &busy);
|
|
else
|
|
/*
|
|
* The cache is empty and will be destroyed soon. Clear
|
|
* the pointer to it in the memcg_caches array so that
|
|
* it will never be accessed even if the root cache
|
|
* stays alive.
|
|
*/
|
|
arr->entries[i] = NULL;
|
|
}
|
|
|
|
/*
|
|
* Second, shutdown all caches left from memory cgroups that are now
|
|
* offline.
|
|
*/
|
|
list_for_each_entry_safe(c, c2, &s->memcg_params.children,
|
|
memcg_params.children_node)
|
|
shutdown_cache(c);
|
|
|
|
list_splice(&busy, &s->memcg_params.children);
|
|
|
|
/*
|
|
* A cache being destroyed must be empty. In particular, this means
|
|
* that all per memcg caches attached to it must be empty too.
|
|
*/
|
|
if (!list_empty(&s->memcg_params.children))
|
|
return -EBUSY;
|
|
return 0;
|
|
}
|
|
|
|
static void flush_memcg_workqueue(struct kmem_cache *s)
|
|
{
|
|
spin_lock_irq(&memcg_kmem_wq_lock);
|
|
s->memcg_params.dying = true;
|
|
spin_unlock_irq(&memcg_kmem_wq_lock);
|
|
|
|
/*
|
|
* SLAB and SLUB deactivate the kmem_caches through call_rcu. Make
|
|
* sure all registered rcu callbacks have been invoked.
|
|
*/
|
|
rcu_barrier();
|
|
|
|
/*
|
|
* SLAB and SLUB create memcg kmem_caches through workqueue and SLUB
|
|
* deactivates the memcg kmem_caches through workqueue. Make sure all
|
|
* previous workitems on workqueue are processed.
|
|
*/
|
|
flush_workqueue(memcg_kmem_cache_wq);
|
|
|
|
/*
|
|
* If we're racing with children kmem_cache deactivation, it might
|
|
* take another rcu grace period to complete their destruction.
|
|
* At this moment the corresponding percpu_ref_kill() call should be
|
|
* done, but it might take another rcu grace period to complete
|
|
* switching to the atomic mode.
|
|
* Please, note that we check without grabbing the slab_mutex. It's safe
|
|
* because at this moment the children list can't grow.
|
|
*/
|
|
if (!list_empty(&s->memcg_params.children))
|
|
rcu_barrier();
|
|
}
|
|
#else
|
|
static inline int shutdown_memcg_caches(struct kmem_cache *s)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static inline void flush_memcg_workqueue(struct kmem_cache *s)
|
|
{
|
|
}
|
|
#endif /* CONFIG_MEMCG_KMEM */
|
|
|
|
void slab_kmem_cache_release(struct kmem_cache *s)
|
|
{
|
|
__kmem_cache_release(s);
|
|
destroy_memcg_params(s);
|
|
kfree_const(s->name);
|
|
kmem_cache_free(kmem_cache, s);
|
|
}
|
|
|
|
void kmem_cache_destroy(struct kmem_cache *s)
|
|
{
|
|
int err;
|
|
|
|
if (unlikely(!s))
|
|
return;
|
|
|
|
flush_memcg_workqueue(s);
|
|
|
|
get_online_cpus();
|
|
get_online_mems();
|
|
|
|
mutex_lock(&slab_mutex);
|
|
|
|
s->refcount--;
|
|
if (s->refcount)
|
|
goto out_unlock;
|
|
|
|
err = shutdown_memcg_caches(s);
|
|
if (!err)
|
|
err = shutdown_cache(s);
|
|
|
|
if (err) {
|
|
pr_err("kmem_cache_destroy %s: Slab cache still has objects\n",
|
|
s->name);
|
|
dump_stack();
|
|
}
|
|
out_unlock:
|
|
mutex_unlock(&slab_mutex);
|
|
|
|
put_online_mems();
|
|
put_online_cpus();
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_destroy);
|
|
|
|
/**
|
|
* kmem_cache_shrink - Shrink a cache.
|
|
* @cachep: The cache to shrink.
|
|
*
|
|
* Releases as many slabs as possible for a cache.
|
|
* To help debugging, a zero exit status indicates all slabs were released.
|
|
*
|
|
* Return: %0 if all slabs were released, non-zero otherwise
|
|
*/
|
|
int kmem_cache_shrink(struct kmem_cache *cachep)
|
|
{
|
|
int ret;
|
|
|
|
get_online_cpus();
|
|
get_online_mems();
|
|
kasan_cache_shrink(cachep);
|
|
ret = __kmem_cache_shrink(cachep);
|
|
put_online_mems();
|
|
put_online_cpus();
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(kmem_cache_shrink);
|
|
|
|
/**
|
|
* kmem_cache_shrink_all - shrink a cache and all memcg caches for root cache
|
|
* @s: The cache pointer
|
|
*/
|
|
void kmem_cache_shrink_all(struct kmem_cache *s)
|
|
{
|
|
struct kmem_cache *c;
|
|
|
|
if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || !is_root_cache(s)) {
|
|
kmem_cache_shrink(s);
|
|
return;
|
|
}
|
|
|
|
get_online_cpus();
|
|
get_online_mems();
|
|
kasan_cache_shrink(s);
|
|
__kmem_cache_shrink(s);
|
|
|
|
/*
|
|
* We have to take the slab_mutex to protect from the memcg list
|
|
* modification.
|
|
*/
|
|
mutex_lock(&slab_mutex);
|
|
for_each_memcg_cache(c, s) {
|
|
/*
|
|
* Don't need to shrink deactivated memcg caches.
|
|
*/
|
|
if (s->flags & SLAB_DEACTIVATED)
|
|
continue;
|
|
kasan_cache_shrink(c);
|
|
__kmem_cache_shrink(c);
|
|
}
|
|
mutex_unlock(&slab_mutex);
|
|
put_online_mems();
|
|
put_online_cpus();
|
|
}
|
|
|
|
bool slab_is_available(void)
|
|
{
|
|
return slab_state >= UP;
|
|
}
|
|
|
|
#ifndef CONFIG_SLOB
|
|
/* Create a cache during boot when no slab services are available yet */
|
|
void __init create_boot_cache(struct kmem_cache *s, const char *name,
|
|
unsigned int size, slab_flags_t flags,
|
|
unsigned int useroffset, unsigned int usersize)
|
|
{
|
|
int err;
|
|
unsigned int align = ARCH_KMALLOC_MINALIGN;
|
|
|
|
s->name = name;
|
|
s->size = s->object_size = size;
|
|
|
|
/*
|
|
* For power of two sizes, guarantee natural alignment for kmalloc
|
|
* caches, regardless of SL*B debugging options.
|
|
*/
|
|
if (is_power_of_2(size))
|
|
align = max(align, size);
|
|
s->align = calculate_alignment(flags, align, size);
|
|
|
|
s->useroffset = useroffset;
|
|
s->usersize = usersize;
|
|
|
|
slab_init_memcg_params(s);
|
|
|
|
err = __kmem_cache_create(s, flags);
|
|
|
|
if (err)
|
|
panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
|
|
name, size, err);
|
|
|
|
s->refcount = -1; /* Exempt from merging for now */
|
|
}
|
|
|
|
struct kmem_cache *__init create_kmalloc_cache(const char *name,
|
|
unsigned int size, slab_flags_t flags,
|
|
unsigned int useroffset, unsigned int usersize)
|
|
{
|
|
struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
|
|
|
|
if (!s)
|
|
panic("Out of memory when creating slab %s\n", name);
|
|
|
|
create_boot_cache(s, name, size, flags, useroffset, usersize);
|
|
list_add(&s->list, &slab_caches);
|
|
memcg_link_cache(s, NULL);
|
|
s->refcount = 1;
|
|
return s;
|
|
}
|
|
|
|
struct kmem_cache *
|
|
kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init =
|
|
{ /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ };
|
|
EXPORT_SYMBOL(kmalloc_caches);
|
|
|
|
/*
|
|
* Conversion table for small slabs sizes / 8 to the index in the
|
|
* kmalloc array. This is necessary for slabs < 192 since we have non power
|
|
* of two cache sizes there. The size of larger slabs can be determined using
|
|
* fls.
|
|
*/
|
|
static u8 size_index[24] __ro_after_init = {
|
|
3, /* 8 */
|
|
4, /* 16 */
|
|
5, /* 24 */
|
|
5, /* 32 */
|
|
6, /* 40 */
|
|
6, /* 48 */
|
|
6, /* 56 */
|
|
6, /* 64 */
|
|
1, /* 72 */
|
|
1, /* 80 */
|
|
1, /* 88 */
|
|
1, /* 96 */
|
|
7, /* 104 */
|
|
7, /* 112 */
|
|
7, /* 120 */
|
|
7, /* 128 */
|
|
2, /* 136 */
|
|
2, /* 144 */
|
|
2, /* 152 */
|
|
2, /* 160 */
|
|
2, /* 168 */
|
|
2, /* 176 */
|
|
2, /* 184 */
|
|
2 /* 192 */
|
|
};
|
|
|
|
static inline unsigned int size_index_elem(unsigned int bytes)
|
|
{
|
|
return (bytes - 1) / 8;
|
|
}
|
|
|
|
/*
|
|
* Find the kmem_cache structure that serves a given size of
|
|
* allocation
|
|
*/
|
|
struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
|
|
{
|
|
unsigned int index;
|
|
|
|
if (size <= 192) {
|
|
if (!size)
|
|
return ZERO_SIZE_PTR;
|
|
|
|
index = size_index[size_index_elem(size)];
|
|
} else {
|
|
if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE))
|
|
return NULL;
|
|
index = fls(size - 1);
|
|
}
|
|
|
|
return kmalloc_caches[kmalloc_type(flags)][index];
|
|
}
|
|
|
|
#ifdef CONFIG_ZONE_DMA
|
|
#define INIT_KMALLOC_INFO(__size, __short_size) \
|
|
{ \
|
|
.name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
|
|
.name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
|
|
.name[KMALLOC_DMA] = "dma-kmalloc-" #__short_size, \
|
|
.size = __size, \
|
|
}
|
|
#else
|
|
#define INIT_KMALLOC_INFO(__size, __short_size) \
|
|
{ \
|
|
.name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
|
|
.name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
|
|
.size = __size, \
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
|
|
* kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
|
|
* kmalloc-67108864.
|
|
*/
|
|
const struct kmalloc_info_struct kmalloc_info[] __initconst = {
|
|
INIT_KMALLOC_INFO(0, 0),
|
|
INIT_KMALLOC_INFO(96, 96),
|
|
INIT_KMALLOC_INFO(192, 192),
|
|
INIT_KMALLOC_INFO(8, 8),
|
|
INIT_KMALLOC_INFO(16, 16),
|
|
INIT_KMALLOC_INFO(32, 32),
|
|
INIT_KMALLOC_INFO(64, 64),
|
|
INIT_KMALLOC_INFO(128, 128),
|
|
INIT_KMALLOC_INFO(256, 256),
|
|
INIT_KMALLOC_INFO(512, 512),
|
|
INIT_KMALLOC_INFO(1024, 1k),
|
|
INIT_KMALLOC_INFO(2048, 2k),
|
|
INIT_KMALLOC_INFO(4096, 4k),
|
|
INIT_KMALLOC_INFO(8192, 8k),
|
|
INIT_KMALLOC_INFO(16384, 16k),
|
|
INIT_KMALLOC_INFO(32768, 32k),
|
|
INIT_KMALLOC_INFO(65536, 64k),
|
|
INIT_KMALLOC_INFO(131072, 128k),
|
|
INIT_KMALLOC_INFO(262144, 256k),
|
|
INIT_KMALLOC_INFO(524288, 512k),
|
|
INIT_KMALLOC_INFO(1048576, 1M),
|
|
INIT_KMALLOC_INFO(2097152, 2M),
|
|
INIT_KMALLOC_INFO(4194304, 4M),
|
|
INIT_KMALLOC_INFO(8388608, 8M),
|
|
INIT_KMALLOC_INFO(16777216, 16M),
|
|
INIT_KMALLOC_INFO(33554432, 32M),
|
|
INIT_KMALLOC_INFO(67108864, 64M)
|
|
};
|
|
|
|
/*
|
|
* Patch up the size_index table if we have strange large alignment
|
|
* requirements for the kmalloc array. This is only the case for
|
|
* MIPS it seems. The standard arches will not generate any code here.
|
|
*
|
|
* Largest permitted alignment is 256 bytes due to the way we
|
|
* handle the index determination for the smaller caches.
|
|
*
|
|
* Make sure that nothing crazy happens if someone starts tinkering
|
|
* around with ARCH_KMALLOC_MINALIGN
|
|
*/
|
|
void __init setup_kmalloc_cache_index_table(void)
|
|
{
|
|
unsigned int i;
|
|
|
|
BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
|
|
(KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
|
|
|
|
for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
|
|
unsigned int elem = size_index_elem(i);
|
|
|
|
if (elem >= ARRAY_SIZE(size_index))
|
|
break;
|
|
size_index[elem] = KMALLOC_SHIFT_LOW;
|
|
}
|
|
|
|
if (KMALLOC_MIN_SIZE >= 64) {
|
|
/*
|
|
* The 96 byte size cache is not used if the alignment
|
|
* is 64 byte.
|
|
*/
|
|
for (i = 64 + 8; i <= 96; i += 8)
|
|
size_index[size_index_elem(i)] = 7;
|
|
|
|
}
|
|
|
|
if (KMALLOC_MIN_SIZE >= 128) {
|
|
/*
|
|
* The 192 byte sized cache is not used if the alignment
|
|
* is 128 byte. Redirect kmalloc to use the 256 byte cache
|
|
* instead.
|
|
*/
|
|
for (i = 128 + 8; i <= 192; i += 8)
|
|
size_index[size_index_elem(i)] = 8;
|
|
}
|
|
}
|
|
|
|
static void __init
|
|
new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
|
|
{
|
|
if (type == KMALLOC_RECLAIM)
|
|
flags |= SLAB_RECLAIM_ACCOUNT;
|
|
|
|
kmalloc_caches[type][idx] = create_kmalloc_cache(
|
|
kmalloc_info[idx].name[type],
|
|
kmalloc_info[idx].size, flags, 0,
|
|
kmalloc_info[idx].size);
|
|
}
|
|
|
|
/*
|
|
* Create the kmalloc array. Some of the regular kmalloc arrays
|
|
* may already have been created because they were needed to
|
|
* enable allocations for slab creation.
|
|
*/
|
|
void __init create_kmalloc_caches(slab_flags_t flags)
|
|
{
|
|
int i;
|
|
enum kmalloc_cache_type type;
|
|
|
|
for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
|
|
for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
|
|
if (!kmalloc_caches[type][i])
|
|
new_kmalloc_cache(i, type, flags);
|
|
|
|
/*
|
|
* Caches that are not of the two-to-the-power-of size.
|
|
* These have to be created immediately after the
|
|
* earlier power of two caches
|
|
*/
|
|
if (KMALLOC_MIN_SIZE <= 32 && i == 6 &&
|
|
!kmalloc_caches[type][1])
|
|
new_kmalloc_cache(1, type, flags);
|
|
if (KMALLOC_MIN_SIZE <= 64 && i == 7 &&
|
|
!kmalloc_caches[type][2])
|
|
new_kmalloc_cache(2, type, flags);
|
|
}
|
|
}
|
|
|
|
/* Kmalloc array is now usable */
|
|
slab_state = UP;
|
|
|
|
#ifdef CONFIG_ZONE_DMA
|
|
for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
|
|
struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];
|
|
|
|
if (s) {
|
|
kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
|
|
kmalloc_info[i].name[KMALLOC_DMA],
|
|
kmalloc_info[i].size,
|
|
SLAB_CACHE_DMA | flags, 0, 0);
|
|
}
|
|
}
|
|
#endif
|
|
}
|
|
#endif /* !CONFIG_SLOB */
|
|
|
|
/*
|
|
* To avoid unnecessary overhead, we pass through large allocation requests
|
|
* directly to the page allocator. We use __GFP_COMP, because we will need to
|
|
* know the allocation order to free the pages properly in kfree.
|
|
*/
|
|
void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
|
|
{
|
|
void *ret = NULL;
|
|
struct page *page;
|
|
|
|
flags |= __GFP_COMP;
|
|
page = alloc_pages(flags, order);
|
|
if (likely(page)) {
|
|
ret = page_address(page);
|
|
mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
|
|
1 << order);
|
|
}
|
|
ret = kasan_kmalloc_large(ret, size, flags);
|
|
/* As ret might get tagged, call kmemleak hook after KASAN. */
|
|
kmemleak_alloc(ret, size, 1, flags);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(kmalloc_order);
|
|
|
|
#ifdef CONFIG_TRACING
|
|
void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
|
|
{
|
|
void *ret = kmalloc_order(size, flags, order);
|
|
trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(kmalloc_order_trace);
|
|
#endif
|
|
|
|
#ifdef CONFIG_SLAB_FREELIST_RANDOM
|
|
/* Randomize a generic freelist */
|
|
static void freelist_randomize(struct rnd_state *state, unsigned int *list,
|
|
unsigned int count)
|
|
{
|
|
unsigned int rand;
|
|
unsigned int i;
|
|
|
|
for (i = 0; i < count; i++)
|
|
list[i] = i;
|
|
|
|
/* Fisher-Yates shuffle */
|
|
for (i = count - 1; i > 0; i--) {
|
|
rand = prandom_u32_state(state);
|
|
rand %= (i + 1);
|
|
swap(list[i], list[rand]);
|
|
}
|
|
}
|
|
|
|
/* Create a random sequence per cache */
|
|
int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
|
|
gfp_t gfp)
|
|
{
|
|
struct rnd_state state;
|
|
|
|
if (count < 2 || cachep->random_seq)
|
|
return 0;
|
|
|
|
cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
|
|
if (!cachep->random_seq)
|
|
return -ENOMEM;
|
|
|
|
/* Get best entropy at this stage of boot */
|
|
prandom_seed_state(&state, get_random_long());
|
|
|
|
freelist_randomize(&state, cachep->random_seq, count);
|
|
return 0;
|
|
}
|
|
|
|
/* Destroy the per-cache random freelist sequence */
|
|
void cache_random_seq_destroy(struct kmem_cache *cachep)
|
|
{
|
|
kfree(cachep->random_seq);
|
|
cachep->random_seq = NULL;
|
|
}
|
|
#endif /* CONFIG_SLAB_FREELIST_RANDOM */
|
|
|
|
#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
|
|
#ifdef CONFIG_SLAB
|
|
#define SLABINFO_RIGHTS (0600)
|
|
#else
|
|
#define SLABINFO_RIGHTS (0400)
|
|
#endif
|
|
|
|
static void print_slabinfo_header(struct seq_file *m)
|
|
{
|
|
/*
|
|
* Output format version, so at least we can change it
|
|
* without _too_ many complaints.
|
|
*/
|
|
#ifdef CONFIG_DEBUG_SLAB
|
|
seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
|
|
#else
|
|
seq_puts(m, "slabinfo - version: 2.1\n");
|
|
#endif
|
|
seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
|
|
seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
|
|
seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
|
|
#ifdef CONFIG_DEBUG_SLAB
|
|
seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
|
|
seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
|
|
#endif
|
|
seq_putc(m, '\n');
|
|
}
|
|
|
|
void *slab_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
mutex_lock(&slab_mutex);
|
|
return seq_list_start(&slab_root_caches, *pos);
|
|
}
|
|
|
|
void *slab_next(struct seq_file *m, void *p, loff_t *pos)
|
|
{
|
|
return seq_list_next(p, &slab_root_caches, pos);
|
|
}
|
|
|
|
void slab_stop(struct seq_file *m, void *p)
|
|
{
|
|
mutex_unlock(&slab_mutex);
|
|
}
|
|
|
|
static void
|
|
memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info)
|
|
{
|
|
struct kmem_cache *c;
|
|
struct slabinfo sinfo;
|
|
|
|
if (!is_root_cache(s))
|
|
return;
|
|
|
|
for_each_memcg_cache(c, s) {
|
|
memset(&sinfo, 0, sizeof(sinfo));
|
|
get_slabinfo(c, &sinfo);
|
|
|
|
info->active_slabs += sinfo.active_slabs;
|
|
info->num_slabs += sinfo.num_slabs;
|
|
info->shared_avail += sinfo.shared_avail;
|
|
info->active_objs += sinfo.active_objs;
|
|
info->num_objs += sinfo.num_objs;
|
|
}
|
|
}
|
|
|
|
static void cache_show(struct kmem_cache *s, struct seq_file *m)
|
|
{
|
|
struct slabinfo sinfo;
|
|
|
|
memset(&sinfo, 0, sizeof(sinfo));
|
|
get_slabinfo(s, &sinfo);
|
|
|
|
memcg_accumulate_slabinfo(s, &sinfo);
|
|
|
|
seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
|
|
cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size,
|
|
sinfo.objects_per_slab, (1 << sinfo.cache_order));
|
|
|
|
seq_printf(m, " : tunables %4u %4u %4u",
|
|
sinfo.limit, sinfo.batchcount, sinfo.shared);
|
|
seq_printf(m, " : slabdata %6lu %6lu %6lu",
|
|
sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
|
|
slabinfo_show_stats(m, s);
|
|
seq_putc(m, '\n');
|
|
}
|
|
|
|
static int slab_show(struct seq_file *m, void *p)
|
|
{
|
|
struct kmem_cache *s = list_entry(p, struct kmem_cache, root_caches_node);
|
|
|
|
if (p == slab_root_caches.next)
|
|
print_slabinfo_header(m);
|
|
cache_show(s, m);
|
|
return 0;
|
|
}
|
|
|
|
void dump_unreclaimable_slab(void)
|
|
{
|
|
struct kmem_cache *s, *s2;
|
|
struct slabinfo sinfo;
|
|
|
|
/*
|
|
* Here acquiring slab_mutex is risky since we don't prefer to get
|
|
* sleep in oom path. But, without mutex hold, it may introduce a
|
|
* risk of crash.
|
|
* Use mutex_trylock to protect the list traverse, dump nothing
|
|
* without acquiring the mutex.
|
|
*/
|
|
if (!mutex_trylock(&slab_mutex)) {
|
|
pr_warn("excessive unreclaimable slab but cannot dump stats\n");
|
|
return;
|
|
}
|
|
|
|
pr_info("Unreclaimable slab info:\n");
|
|
pr_info("Name Used Total\n");
|
|
|
|
list_for_each_entry_safe(s, s2, &slab_caches, list) {
|
|
if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT))
|
|
continue;
|
|
|
|
get_slabinfo(s, &sinfo);
|
|
|
|
if (sinfo.num_objs > 0)
|
|
pr_info("%-17s %10luKB %10luKB\n", cache_name(s),
|
|
(sinfo.active_objs * s->size) / 1024,
|
|
(sinfo.num_objs * s->size) / 1024);
|
|
}
|
|
mutex_unlock(&slab_mutex);
|
|
}
|
|
|
|
#if defined(CONFIG_MEMCG)
|
|
void *memcg_slab_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
|
|
|
|
mutex_lock(&slab_mutex);
|
|
return seq_list_start(&memcg->kmem_caches, *pos);
|
|
}
|
|
|
|
void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos)
|
|
{
|
|
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
|
|
|
|
return seq_list_next(p, &memcg->kmem_caches, pos);
|
|
}
|
|
|
|
void memcg_slab_stop(struct seq_file *m, void *p)
|
|
{
|
|
mutex_unlock(&slab_mutex);
|
|
}
|
|
|
|
int memcg_slab_show(struct seq_file *m, void *p)
|
|
{
|
|
struct kmem_cache *s = list_entry(p, struct kmem_cache,
|
|
memcg_params.kmem_caches_node);
|
|
struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
|
|
|
|
if (p == memcg->kmem_caches.next)
|
|
print_slabinfo_header(m);
|
|
cache_show(s, m);
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* slabinfo_op - iterator that generates /proc/slabinfo
|
|
*
|
|
* Output layout:
|
|
* cache-name
|
|
* num-active-objs
|
|
* total-objs
|
|
* object size
|
|
* num-active-slabs
|
|
* total-slabs
|
|
* num-pages-per-slab
|
|
* + further values on SMP and with statistics enabled
|
|
*/
|
|
static const struct seq_operations slabinfo_op = {
|
|
.start = slab_start,
|
|
.next = slab_next,
|
|
.stop = slab_stop,
|
|
.show = slab_show,
|
|
};
|
|
|
|
static int slabinfo_open(struct inode *inode, struct file *file)
|
|
{
|
|
return seq_open(file, &slabinfo_op);
|
|
}
|
|
|
|
static const struct file_operations proc_slabinfo_operations = {
|
|
.open = slabinfo_open,
|
|
.read = seq_read,
|
|
.write = slabinfo_write,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release,
|
|
};
|
|
|
|
static int __init slab_proc_init(void)
|
|
{
|
|
proc_create("slabinfo", SLABINFO_RIGHTS, NULL,
|
|
&proc_slabinfo_operations);
|
|
return 0;
|
|
}
|
|
module_init(slab_proc_init);
|
|
|
|
#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_MEMCG_KMEM)
|
|
/*
|
|
* Display information about kmem caches that have child memcg caches.
|
|
*/
|
|
static int memcg_slabinfo_show(struct seq_file *m, void *unused)
|
|
{
|
|
struct kmem_cache *s, *c;
|
|
struct slabinfo sinfo;
|
|
|
|
mutex_lock(&slab_mutex);
|
|
seq_puts(m, "# <name> <css_id[:dead|deact]> <active_objs> <num_objs>");
|
|
seq_puts(m, " <active_slabs> <num_slabs>\n");
|
|
list_for_each_entry(s, &slab_root_caches, root_caches_node) {
|
|
/*
|
|
* Skip kmem caches that don't have any memcg children.
|
|
*/
|
|
if (list_empty(&s->memcg_params.children))
|
|
continue;
|
|
|
|
memset(&sinfo, 0, sizeof(sinfo));
|
|
get_slabinfo(s, &sinfo);
|
|
seq_printf(m, "%-17s root %6lu %6lu %6lu %6lu\n",
|
|
cache_name(s), sinfo.active_objs, sinfo.num_objs,
|
|
sinfo.active_slabs, sinfo.num_slabs);
|
|
|
|
for_each_memcg_cache(c, s) {
|
|
struct cgroup_subsys_state *css;
|
|
char *status = "";
|
|
|
|
css = &c->memcg_params.memcg->css;
|
|
if (!(css->flags & CSS_ONLINE))
|
|
status = ":dead";
|
|
else if (c->flags & SLAB_DEACTIVATED)
|
|
status = ":deact";
|
|
|
|
memset(&sinfo, 0, sizeof(sinfo));
|
|
get_slabinfo(c, &sinfo);
|
|
seq_printf(m, "%-17s %4d%-6s %6lu %6lu %6lu %6lu\n",
|
|
cache_name(c), css->id, status,
|
|
sinfo.active_objs, sinfo.num_objs,
|
|
sinfo.active_slabs, sinfo.num_slabs);
|
|
}
|
|
}
|
|
mutex_unlock(&slab_mutex);
|
|
return 0;
|
|
}
|
|
DEFINE_SHOW_ATTRIBUTE(memcg_slabinfo);
|
|
|
|
static int __init memcg_slabinfo_init(void)
|
|
{
|
|
debugfs_create_file("memcg_slabinfo", S_IFREG | S_IRUGO,
|
|
NULL, NULL, &memcg_slabinfo_fops);
|
|
return 0;
|
|
}
|
|
|
|
late_initcall(memcg_slabinfo_init);
|
|
#endif /* CONFIG_DEBUG_FS && CONFIG_MEMCG_KMEM */
|
|
#endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
|
|
|
|
static __always_inline void *__do_krealloc(const void *p, size_t new_size,
|
|
gfp_t flags)
|
|
{
|
|
void *ret;
|
|
size_t ks = 0;
|
|
|
|
if (p)
|
|
ks = ksize(p);
|
|
|
|
if (ks >= new_size) {
|
|
p = kasan_krealloc((void *)p, new_size, flags);
|
|
return (void *)p;
|
|
}
|
|
|
|
ret = kmalloc_track_caller(new_size, flags);
|
|
if (ret && p)
|
|
memcpy(ret, p, ks);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* __krealloc - like krealloc() but don't free @p.
|
|
* @p: object to reallocate memory for.
|
|
* @new_size: how many bytes of memory are required.
|
|
* @flags: the type of memory to allocate.
|
|
*
|
|
* This function is like krealloc() except it never frees the originally
|
|
* allocated buffer. Use this if you don't want to free the buffer immediately
|
|
* like, for example, with RCU.
|
|
*
|
|
* Return: pointer to the allocated memory or %NULL in case of error
|
|
*/
|
|
void *__krealloc(const void *p, size_t new_size, gfp_t flags)
|
|
{
|
|
if (unlikely(!new_size))
|
|
return ZERO_SIZE_PTR;
|
|
|
|
return __do_krealloc(p, new_size, flags);
|
|
|
|
}
|
|
EXPORT_SYMBOL(__krealloc);
|
|
|
|
/**
|
|
* krealloc - reallocate memory. The contents will remain unchanged.
|
|
* @p: object to reallocate memory for.
|
|
* @new_size: how many bytes of memory are required.
|
|
* @flags: the type of memory to allocate.
|
|
*
|
|
* The contents of the object pointed to are preserved up to the
|
|
* lesser of the new and old sizes. If @p is %NULL, krealloc()
|
|
* behaves exactly like kmalloc(). If @new_size is 0 and @p is not a
|
|
* %NULL pointer, the object pointed to is freed.
|
|
*
|
|
* Return: pointer to the allocated memory or %NULL in case of error
|
|
*/
|
|
void *krealloc(const void *p, size_t new_size, gfp_t flags)
|
|
{
|
|
void *ret;
|
|
|
|
if (unlikely(!new_size)) {
|
|
kfree(p);
|
|
return ZERO_SIZE_PTR;
|
|
}
|
|
|
|
ret = __do_krealloc(p, new_size, flags);
|
|
if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
|
|
kfree(p);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(krealloc);
|
|
|
|
/**
|
|
* kzfree - like kfree but zero memory
|
|
* @p: object to free memory of
|
|
*
|
|
* The memory of the object @p points to is zeroed before freed.
|
|
* If @p is %NULL, kzfree() does nothing.
|
|
*
|
|
* Note: this function zeroes the whole allocated buffer which can be a good
|
|
* deal bigger than the requested buffer size passed to kmalloc(). So be
|
|
* careful when using this function in performance sensitive code.
|
|
*/
|
|
void kzfree(const void *p)
|
|
{
|
|
size_t ks;
|
|
void *mem = (void *)p;
|
|
|
|
if (unlikely(ZERO_OR_NULL_PTR(mem)))
|
|
return;
|
|
ks = ksize(mem);
|
|
memset(mem, 0, ks);
|
|
kfree(mem);
|
|
}
|
|
EXPORT_SYMBOL(kzfree);
|
|
|
|
/**
|
|
* ksize - get the actual amount of memory allocated for a given object
|
|
* @objp: Pointer to the object
|
|
*
|
|
* kmalloc may internally round up allocations and return more memory
|
|
* than requested. ksize() can be used to determine the actual amount of
|
|
* memory allocated. The caller may use this additional memory, even though
|
|
* a smaller amount of memory was initially specified with the kmalloc call.
|
|
* The caller must guarantee that objp points to a valid object previously
|
|
* allocated with either kmalloc() or kmem_cache_alloc(). The object
|
|
* must not be freed during the duration of the call.
|
|
*
|
|
* Return: size of the actual memory used by @objp in bytes
|
|
*/
|
|
size_t ksize(const void *objp)
|
|
{
|
|
size_t size;
|
|
|
|
if (WARN_ON_ONCE(!objp))
|
|
return 0;
|
|
/*
|
|
* We need to check that the pointed to object is valid, and only then
|
|
* unpoison the shadow memory below. We use __kasan_check_read(), to
|
|
* generate a more useful report at the time ksize() is called (rather
|
|
* than later where behaviour is undefined due to potential
|
|
* use-after-free or double-free).
|
|
*
|
|
* If the pointed to memory is invalid we return 0, to avoid users of
|
|
* ksize() writing to and potentially corrupting the memory region.
|
|
*
|
|
* We want to perform the check before __ksize(), to avoid potentially
|
|
* crashing in __ksize() due to accessing invalid metadata.
|
|
*/
|
|
if (unlikely(objp == ZERO_SIZE_PTR) || !__kasan_check_read(objp, 1))
|
|
return 0;
|
|
|
|
size = __ksize(objp);
|
|
/*
|
|
* We assume that ksize callers could use whole allocated area,
|
|
* so we need to unpoison this area.
|
|
*/
|
|
kasan_unpoison_shadow(objp, size);
|
|
return size;
|
|
}
|
|
EXPORT_SYMBOL(ksize);
|
|
|
|
/* Tracepoints definitions. */
|
|
EXPORT_TRACEPOINT_SYMBOL(kmalloc);
|
|
EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
|
|
EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
|
|
EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
|
|
EXPORT_TRACEPOINT_SYMBOL(kfree);
|
|
EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
|
|
|
|
int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
|
|
{
|
|
if (__should_failslab(s, gfpflags))
|
|
return -ENOMEM;
|
|
return 0;
|
|
}
|
|
ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
|