From: Oliver Glitta <[email protected]> Many stack traces are similar so there are many similar arrays. Stackdepot saves each unique stack only once.
Replace field addrs in struct track with depot_stack_handle_t handle. Use stackdepot to save stack trace. The benefits are smaller memory overhead and possibility to aggregate per-cache statistics in the future using the stackdepot handle instead of matching stacks manually. Signed-off-by: Oliver Glitta <[email protected]> --- init/Kconfig | 1 + mm/slub.c | 79 ++++++++++++++++++++++++++++++++-------------------- 2 files changed, 50 insertions(+), 30 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 37a17853433a..a4ed2daa6c41 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1891,6 +1891,7 @@ config SLUB_DEBUG default y bool "Enable SLUB debugging support" if EXPERT depends on SLUB && SYSFS + select STACKDEPOT if STACKTRACE_SUPPORT help SLUB has extensive debug support features. Disabling these can result in significant savings in code size. This also disables diff --git a/mm/slub.c b/mm/slub.c index 9c0e26ddf300..4b18499726eb 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -35,6 +35,7 @@ #include <linux/prefetch.h> #include <linux/memcontrol.h> #include <linux/random.h> +#include <linux/stackdepot.h> #include <trace/events/kmem.h> @@ -203,8 +204,8 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s) #define TRACK_ADDRS_COUNT 16 struct track { unsigned long addr; /* Called from address */ -#ifdef CONFIG_STACKTRACE - unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */ +#ifdef CONFIG_STACKDEPOT + depot_stack_handle_t handle; #endif int cpu; /* Was running on cpu */ int pid; /* Pid context */ @@ -581,22 +582,27 @@ static struct track *get_track(struct kmem_cache *s, void *object, return kasan_reset_tag(p + alloc); } +#ifdef CONFIG_STACKDEPOT +static depot_stack_handle_t save_stack_trace(gfp_t flags) +{ + unsigned long entries[TRACK_ADDRS_COUNT]; + depot_stack_handle_t handle; + unsigned int nr_entries; + + nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 4); + handle = stack_depot_save(entries, nr_entries, flags); + return handle; +} +#endif + static void set_track(struct kmem_cache *s, void *object, enum track_item alloc, unsigned long addr) { struct track *p = get_track(s, object, alloc); if (addr) { -#ifdef CONFIG_STACKTRACE - unsigned int nr_entries; - - metadata_access_enable(); - nr_entries = stack_trace_save(kasan_reset_tag(p->addrs), - TRACK_ADDRS_COUNT, 3); - metadata_access_disable(); - - if (nr_entries < TRACK_ADDRS_COUNT) - p->addrs[nr_entries] = 0; +#ifdef CONFIG_STACKDEPOT + p->handle = save_stack_trace(GFP_KERNEL); #endif p->addr = addr; p->cpu = smp_processor_id(); @@ -623,14 +629,19 @@ static void print_track(const char *s, struct track *t, unsigned long pr_time) pr_err("%s in %pS age=%lu cpu=%u pid=%d\n", s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid); -#ifdef CONFIG_STACKTRACE +#ifdef CONFIG_STACKDEPOT { - int i; - for (i = 0; i < TRACK_ADDRS_COUNT; i++) - if (t->addrs[i]) - pr_err("\t%pS\n", (void *)t->addrs[i]); - else - break; + depot_stack_handle_t handle; + unsigned long *entries; + unsigned int nr_entries; + + handle = READ_ONCE(t->handle); + if (!handle) { + pr_err("object allocation/free stack trace missing\n"); + } else { + nr_entries = stack_depot_fetch(handle, &entries); + stack_trace_print(entries, nr_entries, 0); + } } #endif } @@ -4017,18 +4028,26 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page) objp = fixup_red_left(s, objp); trackp = get_track(s, objp, TRACK_ALLOC); kpp->kp_ret = (void *)trackp->addr; -#ifdef CONFIG_STACKTRACE - for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) { - kpp->kp_stack[i] = (void *)trackp->addrs[i]; - if (!kpp->kp_stack[i]) - break; - } +#ifdef CONFIG_STACKDEPOT + { + depot_stack_handle_t handle; + unsigned long *entries; + unsigned int nr_entries; - trackp = get_track(s, objp, TRACK_FREE); - for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) { - kpp->kp_free_stack[i] = (void *)trackp->addrs[i]; - if (!kpp->kp_free_stack[i]) - break; + handle = READ_ONCE(trackp->handle); + if (handle) { + nr_entries = stack_depot_fetch(handle, &entries); + for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++) + kpp->kp_stack[i] = (void *)entries[i]; + } + + trackp = get_track(s, objp, TRACK_FREE); + handle = READ_ONCE(trackp->handle); + if (handle) { + nr_entries = stack_depot_fetch(handle, &entries); + for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++) + kpp->kp_free_stack[i] = (void *)entries[i]; + } } #endif #endif -- 2.31.1.272.g89b43f80a5
