Re: [PATCH v6 13/37] lib: add allocation tagging support for memory allocation profiling

Klara Modin
2024-04-05T13:54:51Z

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Hi,

On 2024-03-21 17:36, Suren Baghdasaryan wrote:
> Introduce CONFIG_MEM_ALLOC_PROFILING which provides definitions to easily
> instrument memory allocators. It registers an "alloc_tags" codetag type
> with /proc/allocinfo interface to output allocation tag information when
> the feature is enabled.
> CONFIG_MEM_ALLOC_PROFILING_DEBUG is provided for debugging the memory
> allocation profiling instrumentation.
> Memory allocation profiling can be enabled or disabled at runtime using
> /proc/sys/vm/mem_profiling sysctl when CONFIG_MEM_ALLOC_PROFILING_DEBUG=n.
> CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT enables memory allocation
> profiling by default.
>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> Co-developed-by: Kent Overstreet <kent.overstreet@linux.dev>
> Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

With this commit (9e2dcefa791e9d14006b360fba3455510fd3325d in
next-20240404), randconfig with KCONFIG_SEED=0xE6264236 fails to build
with the attached error. The following patch fixes the build error for
me, but I don't know if it's correct.

Kind regards,
Klara Modin

diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h
index 100ddf66eb8e..1c765d80298b 100644
--- a/include/linux/alloc_tag.h
+++ b/include/linux/alloc_tag.h
@@ -12,6 +12,7 @@
#include <asm/percpu.h>
#include <linux/cpumask.h>
#include <linux/static_key.h>
+#include <linux/irqflags.h>

struct alloc_tag_counters {
u64 bytes;

> diff --git a/include/linux/alloc_tag.h b/include/linux/alloc_tag.h
> new file mode 100644
> index 000000000000..b970ff1c80dc
> --- /dev/null
> +++ b/include/linux/alloc_tag.h
> @@ -0,0 +1,145 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * allocation tagging
> + */
> +#ifndef _LINUX_ALLOC_TAG_H
> +#define _LINUX_ALLOC_TAG_H
> +
> +#include <linux/bug.h>
> +#include <linux/codetag.h>
> +#include <linux/container_of.h>
> +#include <linux/preempt.h>
> +#include <asm/percpu.h>
> +#include <linux/cpumask.h>
> +#include <linux/static_key.h>
> +
> +struct alloc_tag_counters {
> + u64 bytes;
> + u64 calls;
> +};
> +
> +/*
> + * An instance of this structure is created in a special ELF section at every
> + * allocation callsite. At runtime, the special section is treated as
> + * an array of these. Embedded codetag utilizes codetag framework.
> + */
> +struct alloc_tag {
> + struct codetag ct;
> + struct alloc_tag_counters __percpu *counters;
> +} __aligned(8);
> +
> +#ifdef CONFIG_MEM_ALLOC_PROFILING
> +
> +static inline struct alloc_tag *ct_to_alloc_tag(struct codetag *ct)
> +{
> + return container_of(ct, struct alloc_tag, ct);
> +}
> +
> +#ifdef ARCH_NEEDS_WEAK_PER_CPU
> +/*
> + * When percpu variables are required to be defined as weak, static percpu
> + * variables can't be used inside a function (see comments for DECLARE_PER_CPU_SECTION).
> + */
> +#error "Memory allocation profiling is incompatible with ARCH_NEEDS_WEAK_PER_CPU"
> +#endif
> +
> +#define DEFINE_ALLOC_TAG(_alloc_tag) \
> + static DEFINE_PER_CPU(struct alloc_tag_counters, _alloc_tag_cntr); \
> + static struct alloc_tag _alloc_tag __used __aligned(8) \
> + __section("alloc_tags") = { \
> + .ct = CODE_TAG_INIT, \
> + .counters = &_alloc_tag_cntr };
> +
> +DECLARE_STATIC_KEY_MAYBE(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT,
> + mem_alloc_profiling_key);
> +
> +static inline bool mem_alloc_profiling_enabled(void)
> +{
> + return static_branch_maybe(CONFIG_MEM_ALLOC_PROFILING_ENABLED_BY_DEFAULT,
> + &mem_alloc_profiling_key);
> +}
> +
> +static inline struct alloc_tag_counters alloc_tag_read(struct alloc_tag *tag)
> +{
> + struct alloc_tag_counters v = { 0, 0 };
> + struct alloc_tag_counters *counter;
> + int cpu;
> +
> + for_each_possible_cpu(cpu) {
> + counter = per_cpu_ptr(tag->counters, cpu);
> + v.bytes += counter->bytes;
> + v.calls += counter->calls;
> + }
> +
> + return v;
> +}
> +
> +#ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG
> +static inline void alloc_tag_add_check(union codetag_ref *ref, struct alloc_tag *tag)
> +{
> + WARN_ONCE(ref && ref->ct,
> + "alloc_tag was not cleared (got tag for %s:%u)\n",
> + ref->ct->filename, ref->ct->lineno);
> +
> + WARN_ONCE(!tag, "current->alloc_tag not set");
> +}
> +
> +static inline void alloc_tag_sub_check(union codetag_ref *ref)
> +{
> + WARN_ONCE(ref && !ref->ct, "alloc_tag was not set\n");
> +}
> +#else
> +static inline void alloc_tag_add_check(union codetag_ref *ref, struct alloc_tag *tag) {}
> +static inline void alloc_tag_sub_check(union codetag_ref *ref) {}
> +#endif
> +
> +/* Caller should verify both ref and tag to be valid */
> +static inline void __alloc_tag_ref_set(union codetag_ref *ref, struct alloc_tag *tag)
> +{
> + ref->ct = &tag->ct;
> + /*
> + * We need in increment the call counter every time we have a new
> + * allocation or when we split a large allocation into smaller ones.
> + * Each new reference for every sub-allocation needs to increment call
> + * counter because when we free each part the counter will be decremented.
> + */
> + this_cpu_inc(tag->counters->calls);
> +}
> +
> +static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag, size_t bytes)
> +{
> + alloc_tag_add_check(ref, tag);
> + if (!ref || !tag)
> + return;
> +
> + __alloc_tag_ref_set(ref, tag);
> + this_cpu_add(tag->counters->bytes, bytes);
> +}
> +
> +static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes)
> +{
> + struct alloc_tag *tag;
> +
> + alloc_tag_sub_check(ref);
> + if (!ref || !ref->ct)
> + return;
> +
> + tag = ct_to_alloc_tag(ref->ct);
> +
> + this_cpu_sub(tag->counters->bytes, bytes);
> + this_cpu_dec(tag->counters->calls);
> +
> + ref->ct = NULL;
> +}
> +
> +#else /* CONFIG_MEM_ALLOC_PROFILING */
> +
> +#define DEFINE_ALLOC_TAG(_alloc_tag)
> +static inline bool mem_alloc_profiling_enabled(void) { return false; }
> +static inline void alloc_tag_add(union codetag_ref *ref, struct alloc_tag *tag,
> + size_t bytes) {}
> +static inline void alloc_tag_sub(union codetag_ref *ref, size_t bytes) {}
> +
> +#endif /* CONFIG_MEM_ALLOC_PROFILING */
> +
> +#endif /* _LINUX_ALLOC_TAG_H */

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In file included from ./arch/x86/include/asm/percpu.h:615,
from ./arch/x86/include/asm/preempt.h:6,
from ./include/linux/preempt.h:79,
from ./include/linux/alloc_tag.h:11,
from lib/alloc_tag.c:2:
./include/linux/alloc_tag.h: In function ‘__alloc_tag_ref_set’:
./include/asm-generic/percpu.h:155:9: error: implicit declaration of function ‘raw_local_irq_save’ [-Werror=implicit-function-declaration]
155 | raw_local_irq_save(__flags); \
| ^~~~~~~~~~~~~~~~~~
./include/asm-generic/percpu.h:410:41: note: in expansion of macro ‘this_cpu_generic_to_op’
410 | #define this_cpu_add_8(pcp, val) this_cpu_generic_to_op(pcp, val, +=)
| ^~~~~~~~~~~~~~~~~~~~~~
./include/linux/percpu-defs.h:368:25: note: in expansion of macro ‘this_cpu_add_8’
368 | case 8: stem##8(variable, __VA_ARGS__);break; \
| ^~~~
./include/linux/percpu-defs.h:491:41: note: in expansion of macro ‘__pcpu_size_call’
491 | #define this_cpu_add(pcp, val) __pcpu_size_call(this_cpu_add_, pcp, val)
| ^~~~~~~~~~~~~~~~
./include/linux/percpu-defs.h:501:41: note: in expansion of macro ‘this_cpu_add’
501 | #define this_cpu_inc(pcp) this_cpu_add(pcp, 1)
| ^~~~~~~~~~~~
./include/linux/alloc_tag.h:106:9: note: in expansion of macro ‘this_cpu_inc’
106 | this_cpu_inc(tag->counters->calls);
| ^~~~~~~~~~~~
./include/asm-generic/percpu.h:157:9: error: implicit declaration of function ‘raw_local_irq_restore’ [-Werror=implicit-function-declaration]
157 | raw_local_irq_restore(__flags); \
| ^~~~~~~~~~~~~~~~~~~~~
./include/asm-generic/percpu.h:410:41: note: in expansion of macro ‘this_cpu_generic_to_op’
410 | #define this_cpu_add_8(pcp, val) this_cpu_generic_to_op(pcp, val, +=)
| ^~~~~~~~~~~~~~~~~~~~~~
./include/linux/percpu-defs.h:368:25: note: in expansion of macro ‘this_cpu_add_8’
368 | case 8: stem##8(variable, __VA_ARGS__);break; \
| ^~~~
./include/linux/percpu-defs.h:491:41: note: in expansion of macro ‘__pcpu_size_call’
491 | #define this_cpu_add(pcp, val) __pcpu_size_call(this_cpu_add_, pcp, val)
| ^~~~~~~~~~~~~~~~
./include/linux/percpu-defs.h:501:41: note: in expansion of macro ‘this_cpu_add’
501 | #define this_cpu_inc(pcp) this_cpu_add(pcp, 1)
| ^~~~~~~~~~~~
./include/linux/alloc_tag.h:106:9: note: in expansion of macro ‘this_cpu_inc’
106 | this_cpu_inc(tag->counters->calls);
| ^~~~~~~~~~~~
cc1: some warnings being treated as errors
make[3]: *** [scripts/Makefile.build:244: lib/alloc_tag.o] Error 1
make[2]: *** [scripts/Makefile.build:485: lib] Error 2
make[1]: *** [/home/klara/git/linux/Makefile:1919: .] Error 2
make: *** [Makefile:240: __sub-make] Error 2

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# bad: [2b3d5988ae2cb5cd945ddbc653f0a71706231fdd] Add linux-next specific files for 20240404
git bisect start 'next/master'
# status: waiting for good commit(s), bad commit known
# good: [39cd87c4eb2b893354f3b850f916353f2658ae6f] Linux 6.9-rc2
git bisect good 39cd87c4eb2b893354f3b850f916353f2658ae6f
# bad: [cc7b62666779616ff52d389a344ffe2c041e36e2] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git
git bisect bad cc7b62666779616ff52d389a344ffe2c041e36e2
# bad: [d6b7dd0f8d84f9fdf2af65fceb608e3206276e81] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux.git
git bisect bad d6b7dd0f8d84f9fdf2af65fceb608e3206276e81
# bad: [ad6a31687713a8f12165e730e0eb6e0de3beae56] Merge branch 'mm-everything' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
git bisect bad ad6a31687713a8f12165e730e0eb6e0de3beae56
# good: [59266d9886adb5c9e240129ccc606727fd3a881d] Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git
git bisect good 59266d9886adb5c9e240129ccc606727fd3a881d
# bad: [085e5fe7388cf36ab5c02d91022229e5fade5b30] mm: merge folio_is_secretmem() and folio_fast_pin_allowed() into gup_fast_folio_allowed()
git bisect bad 085e5fe7388cf36ab5c02d91022229e5fade5b30
# bad: [f6a61baa9139d174170acdae8667b3246ce44db6] lib: add memory allocations report in show_mem()
git bisect bad f6a61baa9139d174170acdae8667b3246ce44db6
# good: [302519d9e80a7fbf2cf8d0b8961d491af648759f] asm-generic/io.h: kill vmalloc.h dependency
git bisect good 302519d9e80a7fbf2cf8d0b8961d491af648759f
# bad: [e6942003e682e3883847459c3d07e23c796a2782] mm: create new codetag references during page splitting
git bisect bad e6942003e682e3883847459c3d07e23c796a2782
# good: [ed97151dec736c1541bfac2b801108d54ebee5bc] lib: code tagging module support
git bisect good ed97151dec736c1541bfac2b801108d54ebee5bc
# bad: [95767bde5020afefef4205b60e71f4ebf96da74e] lib: introduce early boot parameter to avoid page_ext memory overhead
git bisect bad 95767bde5020afefef4205b60e71f4ebf96da74e
# bad: [9e2dcefa791e9d14006b360fba3455510fd3325d] lib: add allocation tagging support for memory allocation profiling
git bisect bad 9e2dcefa791e9d14006b360fba3455510fd3325d
# good: [0eccd42fbf9d7c4ae0cbec48cce637da89813c2c] lib: prevent module unloading if memory is not freed
git bisect good 0eccd42fbf9d7c4ae0cbec48cce637da89813c2c
# first bad commit: [9e2dcefa791e9d14006b360fba3455510fd3325d] lib: add allocation tagging support for memory allocation profiling