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authorOliver Glitta <glittao@gmail.com>2021-07-07 18:07:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-07-08 11:48:20 -0700
commit788691464c29455346dc613a3b43c2fb9e5757a4 (patch)
tree9cc94b1811c694b18e10bfeceb6cc9a9ee0b6f21
parent113616ec5b64b23a1c9b663adafadabdfbec0f51 (diff)
downloadlinux-788691464c29455346dc613a3b43c2fb9e5757a4.tar.bz2
mm/slub: use stackdepot to save stack trace in objects
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>
-rw-r--r--init/Kconfig1
-rw-r--r--mm/slub.c79
2 files changed, 50 insertions, 30 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 55f9f7738ebb..bb0d6e6262b1 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -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
diff --git a/mm/slub.c b/mm/slub.c
index 2ee43ff667a5..dc863c1ea324 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -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