[PATCH v4 15/17] mm/slab_common: drop kmem_alloc & avoid dereferencing fields when not using

Hyeonggon Yoo
2022-08-17T10:20:45Z

Drop kmem_alloc event class, and define kmalloc and kmem_cache_alloc
using TRACE_EVENT() macro.

And then this patch does:
- Do not pass pointer to struct kmem_cache to trace_kmalloc.
gfp flag is enough to know if it's accounted or not.
- Avoid dereferencing s->object_size and s->size when not using kmem_cache_alloc event.
- Avoid dereferencing s->name in when not using kmem_cache_free event.
- Adjust s->size to SLOB_UNITS(s->size) * SLOB_UNIT in SLOB

Cc: Vasily Averin <vasily.averin@linux.dev>
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
---
include/trace/events/kmem.h | 64 ++++++++++++++++++++++++-------------
mm/slab.c | 8 ++---
mm/slab_common.c | 16 +++++-----
mm/slob.c | 19 +++++------
mm/slub.c | 8 ++---
5 files changed, 64 insertions(+), 51 deletions(-)

diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index e078ebcdc4b1..8c6f96604244 100644
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -9,17 +9,15 @@
#include <linux/tracepoint.h>
#include <trace/events/mmflags.h>

-DECLARE_EVENT_CLASS(kmem_alloc,
+TRACE_EVENT(kmem_cache_alloc,

TP_PROTO(unsigned long call_site,
const void *ptr,
struct kmem_cache *s,
- size_t bytes_req,
- size_t bytes_alloc,
gfp_t gfp_flags,
int node),

- TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node),
+ TP_ARGS(call_site, ptr, s, gfp_flags, node),

TP_STRUCT__entry(
__field( unsigned long, call_site )
@@ -34,13 +32,13 @@ DECLARE_EVENT_CLASS(kmem_alloc,
TP_fast_assign(
__entry->call_site = call_site;
__entry->ptr = ptr;
- __entry->bytes_req = bytes_req;
- __entry->bytes_alloc = bytes_alloc;
+ __entry->bytes_req = s->object_size;
+ __entry->bytes_alloc = s->size;
__entry->gfp_flags = (__force unsigned long)gfp_flags;
__entry->node = node;
__entry->accounted = IS_ENABLED(CONFIG_MEMCG_KMEM) ?
((gfp_flags & __GFP_ACCOUNT) ||
- (s && s->flags & SLAB_ACCOUNT)) : false;
+ (s->flags & SLAB_ACCOUNT)) : false;
),

TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d accounted=%s",
@@ -53,22 +51,44 @@ DECLARE_EVENT_CLASS(kmem_alloc,
__entry->accounted ? "true" : "false")
);

-DEFINE_EVENT(kmem_alloc, kmalloc,
+TRACE_EVENT(kmalloc,

- TP_PROTO(unsigned long call_site, const void *ptr,
- struct kmem_cache *s, size_t bytes_req, size_t bytes_alloc,
- gfp_t gfp_flags, int node),
+ TP_PROTO(unsigned long call_site,
+ const void *ptr,
+ size_t bytes_req,
+ size_t bytes_alloc,
+ gfp_t gfp_flags,
+ int node),

- TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node)
-);
+ TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags, node),

-DEFINE_EVENT(kmem_alloc, kmem_cache_alloc,
+ TP_STRUCT__entry(
+ __field( unsigned long, call_site )
+ __field( const void *, ptr )
+ __field( size_t, bytes_req )
+ __field( size_t, bytes_alloc )
+ __field( unsigned long, gfp_flags )
+ __field( int, node )
+ ),

- TP_PROTO(unsigned long call_site, const void *ptr,
- struct kmem_cache *s, size_t bytes_req, size_t bytes_alloc,
- gfp_t gfp_flags, int node),
+ TP_fast_assign(
+ __entry->call_site = call_site;
+ __entry->ptr = ptr;
+ __entry->bytes_req = bytes_req;
+ __entry->bytes_alloc = bytes_alloc;
+ __entry->gfp_flags = (__force unsigned long)gfp_flags;
+ __entry->node = node;
+ ),

- TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node)
+ TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d accounted=%s",
+ (void *)__entry->call_site,
+ __entry->ptr,
+ __entry->bytes_req,
+ __entry->bytes_alloc,
+ show_gfp_flags(__entry->gfp_flags),
+ __entry->node,
+ (IS_ENABLED(CONFIG_MEMCG_KMEM) &&
+ (__entry->gfp_flags & __GFP_ACCOUNT)) ? "true" : "false")
);

TRACE_EVENT(kfree,
@@ -93,20 +113,20 @@ TRACE_EVENT(kfree,

TRACE_EVENT(kmem_cache_free,

- TP_PROTO(unsigned long call_site, const void *ptr, const char *name),
+ TP_PROTO(unsigned long call_site, const void *ptr, const struct kmem_cache *s),

- TP_ARGS(call_site, ptr, name),
+ TP_ARGS(call_site, ptr, s),

TP_STRUCT__entry(
__field( unsigned long, call_site )
__field( const void *, ptr )
- __string( name, name )
+ __string( name, s->name )
),

TP_fast_assign(
__entry->call_site = call_site;
__entry->ptr = ptr;
- __assign_str(name, name);
+ __assign_str(name, s->name);
),

TP_printk("call_site=%pS ptr=%p name=%s",
diff --git a/mm/slab.c b/mm/slab.c
index 2fd400203ac2..a5486ff8362a 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3440,8 +3440,7 @@ void *__kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
{
void *ret = slab_alloc(cachep, lru, flags, cachep->object_size, _RET_IP_);

- trace_kmem_cache_alloc(_RET_IP_, ret, cachep, cachep->object_size,
- cachep->size, flags, NUMA_NO_NODE);
+ trace_kmem_cache_alloc(_RET_IP_, ret, cachep, flags, NUMA_NO_NODE);

return ret;
}
@@ -3536,8 +3535,7 @@ void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
{
void *ret = slab_alloc_node(cachep, NULL, flags, nodeid, cachep->object_size, _RET_IP_);

- trace_kmem_cache_alloc(_RET_IP_, ret, cachep, cachep->object_size,
- cachep->size, flags, nodeid);
+ trace_kmem_cache_alloc(_RET_IP_, ret, cachep, flags, nodeid);

return ret;
}
@@ -3607,7 +3605,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
if (!cachep)
return;

- trace_kmem_cache_free(_RET_IP_, objp, cachep->name);
+ trace_kmem_cache_free(_RET_IP_, objp, cachep);
__do_kmem_cache_free(cachep, objp, _RET_IP_);
}
EXPORT_SYMBOL(kmem_cache_free);
diff --git a/mm/slab_common.c b/mm/slab_common.c
index f34be57b00c8..e53016c9a6e9 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -907,7 +907,7 @@ void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller

if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
ret = __kmalloc_large_node(size, flags, node);
- trace_kmalloc(_RET_IP_, ret, NULL, size,
+ trace_kmalloc(_RET_IP_, ret, size,
PAGE_SIZE << get_order(size), flags, node);
return ret;
}
@@ -919,7 +919,7 @@ void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller

ret = __kmem_cache_alloc_node(s, flags, node, size, caller);
ret = kasan_kmalloc(s, ret, size, flags);
- trace_kmalloc(_RET_IP_, ret, s, size, s->size, flags, node);
+ trace_kmalloc(_RET_IP_, ret, size, s->size, flags, node);
return ret;
}

@@ -1005,7 +1005,7 @@ void *kmalloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
void *ret = __kmem_cache_alloc_node(s, gfpflags, NUMA_NO_NODE,
size, _RET_IP_);

- trace_kmalloc(_RET_IP_, ret, s, size, s->size, gfpflags, NUMA_NO_NODE);
+ trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, NUMA_NO_NODE);

ret = kasan_kmalloc(s, ret, size, gfpflags);
return ret;
@@ -1017,7 +1017,7 @@ void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
{
void *ret = __kmem_cache_alloc_node(s, gfpflags, node, size, _RET_IP_);

- trace_kmalloc(_RET_IP_, ret, s, size, s->size, gfpflags, node);
+ trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, node);

ret = kasan_kmalloc(s, ret, size, gfpflags);
return ret;
@@ -1072,8 +1072,8 @@ void *kmalloc_large(size_t size, gfp_t flags)
{
void *ret = __kmalloc_large_node(size, flags, NUMA_NO_NODE);

- trace_kmalloc(_RET_IP_, ret, NULL, size,
- PAGE_SIZE << get_order(size), flags, NUMA_NO_NODE);
+ trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
+ flags, NUMA_NO_NODE);
return ret;
}
EXPORT_SYMBOL(kmalloc_large);
@@ -1082,8 +1082,8 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node)
{
void *ret = __kmalloc_large_node(size, flags, node);

- trace_kmalloc(_RET_IP_, ret, NULL, size,
- PAGE_SIZE << get_order(size), flags, node);
+ trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
+ flags, node);
return ret;
}
EXPORT_SYMBOL(kmalloc_large_node);
diff --git a/mm/slob.c b/mm/slob.c
index 3208c56d8f82..771af84576bf 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -507,8 +507,7 @@ __do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller)
*m = size;
ret = (void *)m + minalign;

- trace_kmalloc(caller, ret, NULL, size,
- size + minalign, gfp, node);
+ trace_kmalloc(caller, ret, size, size + minalign, gfp, node);
} else {
unsigned int order = get_order(size);

@@ -516,8 +515,7 @@ __do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller)
gfp |= __GFP_COMP;
ret = slob_new_pages(gfp, order, node);

- trace_kmalloc(caller, ret, NULL, size,
- PAGE_SIZE << order, gfp, node);
+ trace_kmalloc(caller, ret, size, PAGE_SIZE << order, gfp, node);
}

kmemleak_alloc(ret, size, 1, gfp);
@@ -594,6 +592,9 @@ int __kmem_cache_create(struct kmem_cache *c, slab_flags_t flags)
/* leave room for rcu footer at the end of object */
c->size += sizeof(struct slob_rcu);
}
+
+ /* Actual size allocated */
+ c->size = SLOB_UNITS(c->size) * SLOB_UNIT;
c->flags = flags;
return 0;
}
@@ -608,14 +609,10 @@ static void *slob_alloc_node(struct kmem_cache *c, gfp_t flags, int node)

if (c->size < PAGE_SIZE) {
b = slob_alloc(c->size, flags, c->align, node, 0);
- trace_kmem_cache_alloc(_RET_IP_, b, NULL, c->object_size,
- SLOB_UNITS(c->size) * SLOB_UNIT,
- flags, node);
+ trace_kmem_cache_alloc(_RET_IP_, b, c, flags, node);
} else {
b = slob_new_pages(flags, get_order(c->size), node);
- trace_kmem_cache_alloc(_RET_IP_, b, NULL, c->object_size,
- PAGE_SIZE << get_order(c->size),
- flags, node);
+ trace_kmem_cache_alloc(_RET_IP_, b, c, flags, node);
}

if (b && c->ctor) {
@@ -671,7 +668,7 @@ static void kmem_rcu_free(struct rcu_head *head)
void kmem_cache_free(struct kmem_cache *c, void *b)
{
kmemleak_free_recursive(b, c->flags);
- trace_kmem_cache_free(_RET_IP_, b, c->name);
+ trace_kmem_cache_free(_RET_IP_, b, c);
if (unlikely(c->flags & SLAB_TYPESAFE_BY_RCU)) {
struct slob_rcu *slob_rcu;
slob_rcu = b + (c->size - sizeof(struct slob_rcu));
diff --git a/mm/slub.c b/mm/slub.c
index 22e4ccf06638..8083a6ee5f15 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3243,8 +3243,7 @@ void *__kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
{
void *ret = slab_alloc(s, lru, gfpflags, _RET_IP_, s->object_size);

- trace_kmem_cache_alloc(_RET_IP_, ret, s, s->object_size,
- s->size, gfpflags, NUMA_NO_NODE);
+ trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);

return ret;
}
@@ -3274,8 +3273,7 @@ void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
{
void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);

- trace_kmem_cache_alloc(_RET_IP_, ret, s, s->object_size,
- s->size, gfpflags, node);
+ trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, node);

return ret;
}
@@ -3517,7 +3515,7 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
s = cache_from_obj(s, x);
if (!s)
return;
- trace_kmem_cache_free(_RET_IP_, x, s->name);
+ trace_kmem_cache_free(_RET_IP_, x, s);
slab_free(s, virt_to_slab(x), x, NULL, &x, 1, _RET_IP_);
}
EXPORT_SYMBOL(kmem_cache_free);
--
2.32.0