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
 18struct 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 */
 28struct alloc_tag {
 29	struct codetag			ct;
 30	struct alloc_tag_counters __percpu	*counters;
 31} __aligned(8);
 32
 33struct alloc_tag_kernel_section {
 34	struct alloc_tag *first_tag;
 35	unsigned long count;
 36};
 37
 38struct 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
 52static inline bool is_codetag_empty(union codetag_ref *ref)
 53{
 54	return ref->ct == CODETAG_EMPTY;
 55}
 56
 57static 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
 65static inline bool is_codetag_empty(union codetag_ref *ref) { return false; }
 66
 67static inline void set_codetag_empty(union codetag_ref *ref)
 68{
 69	if (ref)
 70		ref->ct = NULL;
 71}
 72
 73#endif /* CONFIG_MEM_ALLOC_PROFILING_DEBUG */
 74
 75#ifdef CONFIG_MEM_ALLOC_PROFILING
 76
 77#define ALLOC_TAG_SECTION_NAME	"alloc_tags"
 78
 79struct codetag_bytes {
 80	struct codetag *ct;
 81	s64 bytes;
 82};
 83
 84size_t alloc_tag_top_users(struct codetag_bytes *tags, size_t count, bool can_sleep);
 85
 86static inline struct alloc_tag *ct_to_alloc_tag(struct codetag *ct)
 87{
 88	return container_of(ct, struct alloc_tag, ct);
 89}
 90
 91#if defined(CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU) && defined(MODULE)
 92/*
 93 * When percpu variables are required to be defined as weak, static percpu
 94 * variables can't be used inside a function (see comments for DECLARE_PER_CPU_SECTION).
 95 * Instead we will account all module allocations to a single counter.
 96 */
 97DECLARE_PER_CPU(struct alloc_tag_counters, _shared_alloc_tag);
 98
 99#define DEFINE_ALLOC_TAG(_alloc_tag)						\
100	static struct alloc_tag _alloc_tag __used __aligned(8)			\
101	__section(ALLOC_TAG_SECTION_NAME) = {					\
102		.ct = CODE_TAG_INIT,						\
103		.counters = &_shared_alloc_tag };
104
105#else /* CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU && MODULE */
106
107#ifdef MODULE
108
109#define DEFINE_ALLOC_TAG(_alloc_tag)						\
110	static struct alloc_tag _alloc_tag __used __aligned(8)			\
111	__section(ALLOC_TAG_SECTION_NAME) = {					\
112		.ct = CODE_TAG_INIT,						\
113		.counters = NULL };
114
115#else  /* MODULE */
116
117#define DEFINE_ALLOC_TAG(_alloc_tag)						\
118	static DEFINE_PER_CPU(struct alloc_tag_counters, _alloc_tag_cntr);	\
119	static struct alloc_tag _alloc_tag __used __aligned(8)			\
120	__section(ALLOC_TAG_SECTION_NAME) = {					\
121		.ct = CODE_TAG_INIT,						\
122		.counters = &_alloc_tag_cntr };
123
124#endif /* MODULE */
125
126#endif /* CONFIG_ARCH_MODULE_NEEDS_WEAK_PER_CPU && MODULE */
127
128DECLARE_STATIC_KEY_MAYBE(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT,
129			mem_alloc_profiling_key);
130
131static inline bool mem_alloc_profiling_enabled(void)
132{
133	return static_branch_maybe(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT,
134				   &mem_alloc_profiling_key);
135}
136
137static inline struct alloc_tag_counters alloc_tag_read(struct alloc_tag *tag)
138{
139	struct alloc_tag_counters v = { 0, 0 };
140	struct alloc_tag_counters *counter;
141	int cpu;
142
143	for_each_possible_cpu(cpu) {
144		counter = per_cpu_ptr(tag->counters, cpu);
145		v.bytes += counter->bytes;
146		v.calls += counter->calls;
147	}
148
149	return v;
150}
151
152#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG
153static inline void alloc_tag_add_check(union codetag_ref *ref, struct alloc_tag *tag)
154{
155	WARN_ONCE(ref && ref->ct && !is_codetag_empty(ref),
156		  "alloc_tag was not cleared (got tag for %s:%u)\n",
157		  ref->ct->filename, ref->ct->lineno);
158
159	WARN_ONCE(!tag, "current->alloc_tag not set\n");
160}
161
162static inline void alloc_tag_sub_check(union codetag_ref *ref)
163{
164	WARN_ONCE(ref && !ref->ct, "alloc_tag was not set\n");
165}
166#else
167static inline void alloc_tag_add_check(union codetag_ref *ref, struct alloc_tag *tag) {}
168static inline void alloc_tag_sub_check(union codetag_ref *ref) {}
169#endif
170
171/* Caller should verify both ref and tag to be valid */
172static inline bool __alloc_tag_ref_set(union codetag_ref *ref, struct alloc_tag *tag)
173{
174	alloc_tag_add_check(ref, tag);
175	if (!ref || !tag)
176		return false;
177
178	ref->ct = &tag->ct;
179	return true;
180}
181
182static inline bool alloc_tag_ref_set(union codetag_ref *ref, struct alloc_tag *tag)
183{
184	if (unlikely(!__alloc_tag_ref_set(ref, tag)))
185		return false;
186
187	/*
188	 * We need in increment the call counter every time we have a new
189	 * allocation or when we split a large allocation into smaller ones.
190	 * Each new reference for every sub-allocation needs to increment call
191	 * counter because when we free each part the counter will be decremented.
192	 */
193	this_cpu_inc(tag->counters->calls);
194	return true;
195}
196
197static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag, size_t bytes)
198{
199	if (likely(alloc_tag_ref_set(ref, tag)))
200		this_cpu_add(tag->counters->bytes, bytes);
201}
202
203static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes)
204{
205	struct alloc_tag *tag;
206
207	alloc_tag_sub_check(ref);
208	if (!ref || !ref->ct)
209		return;
210
211	if (is_codetag_empty(ref)) {
212		ref->ct = NULL;
213		return;
214	}
215
216	tag = ct_to_alloc_tag(ref->ct);
217
218	this_cpu_sub(tag->counters->bytes, bytes);
219	this_cpu_dec(tag->counters->calls);
220
221	ref->ct = NULL;
222}
223
224static inline void alloc_tag_set_inaccurate(struct alloc_tag *tag)
225{
226	tag->ct.flags |= CODETAG_FLAG_INACCURATE;
227}
228
229static inline bool alloc_tag_is_inaccurate(struct alloc_tag *tag)
230{
231	return !!(tag->ct.flags & CODETAG_FLAG_INACCURATE);
232}
233
234#define alloc_tag_record(p)	((p) = current->alloc_tag)
235
236#else /* CONFIG_MEM_ALLOC_PROFILING */
237
238#define DEFINE_ALLOC_TAG(_alloc_tag)
239static inline bool mem_alloc_profiling_enabled(void) { return false; }
240static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag,
241				 size_t bytes) {}
242static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes) {}
243static inline void alloc_tag_set_inaccurate(struct alloc_tag *tag) {}
244static inline bool alloc_tag_is_inaccurate(struct alloc_tag *tag) { return false; }
245#define alloc_tag_record(p)	do {} while (0)
246
247#endif /* CONFIG_MEM_ALLOC_PROFILING */
248
249#define alloc_hooks_tag(_tag, _do_alloc)				\
250({									\
251	typeof(_do_alloc) _res;						\
252	if (mem_alloc_profiling_enabled()) {				\
253		struct alloc_tag * __maybe_unused _old;			\
254		_old = alloc_tag_save(_tag);				\
255		_res = _do_alloc;					\
256		alloc_tag_restore(_tag, _old);				\
257	} else								\
258		_res = _do_alloc;					\
259	_res;								\
260})
261
262#define alloc_hooks(_do_alloc)						\
263({									\
264	DEFINE_ALLOC_TAG(_alloc_tag);					\
265	alloc_hooks_tag(&_alloc_tag, _do_alloc);			\
266})
267
268#endif /* _LINUX_ALLOC_TAG_H */