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mm/slub: use stackdepot to save stack trace in objects

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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.

[rdunlap@infradead.org: rename save_stack_trace()]
  Link: https://lkml.kernel.org/r/20210513051920.29320-1-rdunlap@infradead.org
[vbabka@suse.cz: fix lockdep splat]
  Link: https://lkml.kernel.org/r/20210516195150.26740-1-vbabka@suse.czLink: https://lkml.kernel.org/r/20210414163434.4376-1-glittao@gmail.com

Signed-off-by: Oliver Glitta <glittao@gmail.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oliver Glitta 2021-07-07 18:07:47 -07:00 committed by Linus Torvalds
parent 113616ec5b
commit 788691464c
2 changed files with 50 additions and 30 deletions
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1
init/Kconfig
View File

@ -1847,6 +1847,7 @@ 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

79
mm/slub.c
View File

@ -26,6 +26,7 @@
#include <linux/cpuset.h>
#include <linux/mempolicy.h>
#include <linux/ctype.h>
#include <linux/stackdepot.h>
#include <linux/debugobjects.h>
#include <linux/kallsyms.h>
#include <linux/kfence.h>
@ -220,8 +221,8 @@ 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 */
@ -625,22 +626,27 @@ 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_depot_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_depot_trace(GFP_NOWAIT);
#endif
p->addr = addr;
p->cpu = smp_processor_id();
@ -667,14 +673,19 @@ 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
}
@ -4048,18 +4059,26 @@ 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