include/linux/alloc_tag.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * allocation tagging
   4  */
   5 #ifndef _LINUX_ALLOC_TAG_H
   6 #define _LINUX_ALLOC_TAG_H
   7
   8 #include <linux/bug.h>
   9 #include <linux/codetag.h>
  10 #include <linux/container_of.h>
  11 #include <linux/preempt.h>
  12 #include <asm/percpu.h>
  13 #include <linux/cpumask.h>
  14 #include <linux/smp.h>
  15 #include <linux/static_key.h>
  16 #include <linux/irqflags.h>
  17
  18 struct alloc_tag_counters {
  19         u64 bytes;
  20         u64 calls;
  21 };
  22
  23 /*
  24  * An instance of this structure is created in a special ELF section at every
  25  * allocation callsite. At runtime, the special section is treated as
  26  * an array of these. Embedded codetag utilizes codetag framework.
  27  */
  28 struct alloc_tag {
  29         struct codetag                  ct;
  30         struct alloc_tag_counters __percpu      *counters;
  31 } __aligned(8);
  32
  33 struct alloc_tag_kernel_section {
  34         struct alloc_tag *first_tag;
  35         unsigned long count;
  36 };
  37
  38 struct alloc_tag_module_section {
  39         union {
  40                 unsigned long start_addr;
  41                 struct alloc_tag *first_tag;
  42         };
  43         unsigned long end_addr;
  44         /* used size */
  45         unsigned long size;
  46 };
  47
  48 #ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG
  49
  50 #define CODETAG_EMPTY   ((void *)1)
  51
  52 static inline bool is_codetag_empty(union codetag_ref *ref)
  53 {
  54         return ref->ct == CODETAG_EMPTY;
  55 }
  56
  57 static inline void set_codetag_empty(union codetag_ref *ref)
  58 {
  59         if (ref)
  60                 ref->ct = CODETAG_EMPTY;
  61 }
  62
  63 #else /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
  64
  65 static inline bool is_codetag_empty(union codetag_ref *ref) { return false; }
  66 static inline void set_codetag_empty(union codetag_ref *ref) {}
  67
  68 #endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
  69
  70 #ifdef CONFIG_MEM_ALLOC_PROFILING
  71
  72 #define ALLOC_TAG_SECTION_NAME  "alloc_tags"
  73
  74 struct codetag_bytes {
  75         struct codetag *ct;
  76         s64 bytes;
  77 };
  78
  79 size_t alloc_tag_top_users(struct codetag_bytes *tags, size_t count, bool can_sleep);
  80
  81 static inline struct alloc_tag *ct_to_alloc_tag(struct codetag *ct)
  82 {
  83         return container_of(ct, struct alloc_tag, ct);
  84 }
  85
  86 #ifdef ARCH_NEEDS_WEAK_PER_CPU
  87 /*
  88  * When percpu variables are required to be defined as weak, static percpu
  89  * variables can't be used inside a function (see comments for DECLARE_PER_CPU_SECTION).
  90  * Instead we will account all module allocations to a single counter.
  91  */
  92 DECLARE_PER_CPU(struct alloc_tag_counters, _shared_alloc_tag);
  93
  94 #define DEFINE_ALLOC_TAG(_alloc_tag)                                            \
  95         static struct alloc_tag _alloc_tag __used __aligned(8)                  \
  96         __section(ALLOC_TAG_SECTION_NAME) = {                                   \
  97                 .ct = CODE_TAG_INIT,                                            \
  98                 .counters = &_shared_alloc_tag };
  99
 100 #else /* ARCH_NEEDS_WEAK_PER_CPU */
 101
 102 #define DEFINE_ALLOC_TAG(_alloc_tag)                                            \
 103         static DEFINE_PER_CPU(struct alloc_tag_counters, _alloc_tag_cntr);      \
 104         static struct alloc_tag _alloc_tag __used __aligned(8)                  \
 105         __section(ALLOC_TAG_SECTION_NAME) = {                                   \
 106                 .ct = CODE_TAG_INIT,                                            \
 107                 .counters = &_alloc_tag_cntr };
 108
 109 #endif /* ARCH_NEEDS_WEAK_PER_CPU */
 110
 111 DECLARE_STATIC_KEY_MAYBE(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT,
 112                         mem_alloc_profiling_key);
 113
 114 static inline bool mem_alloc_profiling_enabled(void)
 115 {
 116         return static_branch_maybe(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT,
 117                                    &mem_alloc_profiling_key);
 118 }
 119
 120 static inline struct alloc_tag_counters alloc_tag_read(struct alloc_tag *tag)
 121 {
 122         struct alloc_tag_counters v = { 0, 0 };
 123         struct alloc_tag_counters *counter;
 124         int cpu;
 125
 126         for_each_possible_cpu(cpu) {
 127                 counter = per_cpu_ptr(tag->counters, cpu);
 128                 v.bytes += counter->bytes;
 129                 v.calls += counter->calls;
 130         }
 131
 132         return v;
 133 }
 134
 135 #ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG
 136 static inline void alloc_tag_add_check(union codetag_ref *ref, struct alloc_tag *tag)
 137 {
 138         WARN_ONCE(ref && ref->ct,
 139                   "alloc_tag was not cleared (got tag for %s:%u)\n",
 140                   ref->ct->filename, ref->ct->lineno);
 141
 142         WARN_ONCE(!tag, "current->alloc_tag not set\n");
 143 }
 144
 145 static inline void alloc_tag_sub_check(union codetag_ref *ref)
 146 {
 147         WARN_ONCE(ref && !ref->ct, "alloc_tag was not set\n");
 148 }
 149 #else
 150 static inline void alloc_tag_add_check(union codetag_ref *ref, struct alloc_tag *tag) {}
 151 static inline void alloc_tag_sub_check(union codetag_ref *ref) {}
 152 #endif
 153
 154 /* Caller should verify both ref and tag to be valid */
 155 static inline bool __alloc_tag_ref_set(union codetag_ref *ref, struct alloc_tag *tag)
 156 {
 157         alloc_tag_add_check(ref, tag);
 158         if (!ref || !tag)
 159                 return false;
 160
 161         ref->ct = &tag->ct;
 162         return true;
 163 }
 164
 165 static inline bool alloc_tag_ref_set(union codetag_ref *ref, struct alloc_tag *tag)
 166 {
 167         if (unlikely(!__alloc_tag_ref_set(ref, tag)))
 168                 return false;
 169
 170         /*
 171          * We need in increment the call counter every time we have a new
 172          * allocation or when we split a large allocation into smaller ones.
 173          * Each new reference for every sub-allocation needs to increment call
 174          * counter because when we free each part the counter will be decremented.
 175          */
 176         this_cpu_inc(tag->counters->calls);
 177         return true;
 178 }
 179
 180 static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag, size_t bytes)
 181 {
 182         if (likely(alloc_tag_ref_set(ref, tag)))
 183                 this_cpu_add(tag->counters->bytes, bytes);
 184 }
 185
 186 static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes)
 187 {
 188         struct alloc_tag *tag;
 189
 190         alloc_tag_sub_check(ref);
 191         if (!ref || !ref->ct)
 192                 return;
 193
 194         if (is_codetag_empty(ref)) {
 195                 ref->ct = NULL;
 196                 return;
 197         }
 198
 199         tag = ct_to_alloc_tag(ref->ct);
 200
 201         this_cpu_sub(tag->counters->bytes, bytes);
 202         this_cpu_dec(tag->counters->calls);
 203
 204         ref->ct = NULL;
 205 }
 206
 207 #define alloc_tag_record(p)     ((p) = current->alloc_tag)
 208
 209 #else /* CONFIG_MEM_ALLOC_PROFILING */
 210
 211 #define DEFINE_ALLOC_TAG(_alloc_tag)
 212 static inline bool mem_alloc_profiling_enabled(void) { return false; }
 213 static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag,
 214                                  size_t bytes) {}
 215 static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes) {}
 216 #define alloc_tag_record(p)     do {} while (0)
 217
 218 #endif /* CONFIG_MEM_ALLOC_PROFILING */
 219
 220 #define alloc_hooks_tag(_tag, _do_alloc)                                \
 221 ({                                                                      \
 222         struct alloc_tag * __maybe_unused _old = alloc_tag_save(_tag);  \
 223         typeof(_do_alloc) _res = _do_alloc;                             \
 224         alloc_tag_restore(_tag, _old);                                  \
 225         _res;                                                           \
 226 })
 227
 228 #define alloc_hooks(_do_alloc)                                          \
 229 ({                                                                      \
 230         DEFINE_ALLOC_TAG(_alloc_tag);                                   \
 231         alloc_hooks_tag(&_alloc_tag, _do_alloc);                        \
 232 })
 233
 234 #endif /* _LINUX_ALLOC_TAG_H */