[PATCH v2] tracing: add ACCOUNT flag for allocations from marked slab caches

From: Vasily Averin
Date: Tue May 17 2022 - 05:45:31 EST


dSlab caches marked with SLAB_ACCOUNT force accounting for every
allocation from this cache even if __GFP_ACCOUNT flag is not passed.
Unfortunately, at the moment this flag is not visible in ftrace output,
and this makes it difficult to analyze the accounted allocations.

This patch adds the __GFP_ACCOUNT flag for allocations from slab caches
marked with SLAB_ACCOUNT to the ftrace output
---
v2:
1) handle kmem_cache_alloc_node() too, thanks to Shakeel
2) rework kmem_cache_alloc* tracepoints to use cachep instead
of current cachep->*size parameters. Now kmalloc[_node] and
kmem_cache_alloc[_node] tracepoints do not use common template

NB: kmem_cache_alloc_node tracepoint in SLOB cannot be switched to cachep,
therefore it was replaced by kmalloc_node tracepoint.
---
VvS: is this acceptable? Maybe I should split this patch?

Signed-off-by: Vasily Averin <vvs@xxxxxxxxxx>
---
include/trace/events/kmem.h | 82 +++++++++++++++++++++++++++----------
mm/slab.c | 7 +---
mm/slab_common.c | 7 ++--
mm/slob.c | 10 ++---
mm/slub.c | 6 +--
5 files changed, 71 insertions(+), 41 deletions(-)

diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
index 71c141804222..3b4f96e4a607 100644
--- a/include/trace/events/kmem.h
+++ b/include/trace/events/kmem.h
@@ -9,7 +9,7 @@
#include <linux/tracepoint.h>
#include <trace/events/mmflags.h>

-DECLARE_EVENT_CLASS(kmem_alloc,
+TRACE_EVENT(kmalloc,

TP_PROTO(unsigned long call_site,
const void *ptr,
@@ -43,23 +43,41 @@ DECLARE_EVENT_CLASS(kmem_alloc,
show_gfp_flags(__entry->gfp_flags))
);

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

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

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

-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 )
+ ),

- TP_PROTO(unsigned long call_site, const void *ptr,
- size_t bytes_req, size_t bytes_alloc, gfp_t gfp_flags),
+ TP_fast_assign(
+ __entry->call_site = call_site;
+ __entry->ptr = ptr;
+ __entry->bytes_req = s->object_size;
+ __entry->bytes_alloc = s->size;
+ __entry->gfp_flags = (__force unsigned long)gfp_flags |
+ (s->flags & SLAB_ACCOUNT ? __GFP_ACCOUNT : 0);
+ ),

- TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags)
+ TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s",
+ (void *)__entry->call_site,
+ __entry->ptr,
+ __entry->bytes_req,
+ __entry->bytes_alloc,
+ show_gfp_flags(__entry->gfp_flags))
);

-DECLARE_EVENT_CLASS(kmem_alloc_node,
+TRACE_EVENT(kmalloc_node,

TP_PROTO(unsigned long call_site,
const void *ptr,
@@ -97,22 +115,42 @@ DECLARE_EVENT_CLASS(kmem_alloc_node,
__entry->node)
);

-DEFINE_EVENT(kmem_alloc_node, kmalloc_node,
+TRACE_EVENT(kmem_cache_alloc_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_PROTO(unsigned long call_site,
+ const void *ptr,
+ struct kmem_cache *s,
+ gfp_t gfp_flags,
+ int node),

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

-DEFINE_EVENT(kmem_alloc_node, kmem_cache_alloc_node,
+ 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,
- 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 = s->object_size;
+ __entry->bytes_alloc = s->size;
+ __entry->gfp_flags = (__force unsigned long)gfp_flags |
+ (s->flags & SLAB_ACCOUNT ? __GFP_ACCOUNT : 0);
+ __entry->node = node;
+ ),

- TP_ARGS(call_site, ptr, 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",
+ (void *)__entry->call_site,
+ __entry->ptr,
+ __entry->bytes_req,
+ __entry->bytes_alloc,
+ show_gfp_flags(__entry->gfp_flags),
+ __entry->node)
);

TRACE_EVENT(kfree,
diff --git a/mm/slab.c b/mm/slab.c
index 0edb474edef1..935b1c90d7f0 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3492,8 +3492,7 @@ 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->object_size, cachep->size, flags);
+ trace_kmem_cache_alloc(_RET_IP_, ret, cachep, flags);

return ret;
}
@@ -3606,9 +3605,7 @@ void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
{
void *ret = slab_alloc_node(cachep, flags, nodeid, cachep->object_size, _RET_IP_);

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

return ret;
}
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 2b3206a2c3b5..12299cf450fe 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -25,13 +25,12 @@
#include <asm/page.h>
#include <linux/memcontrol.h>

-#define CREATE_TRACE_POINTS
-#include <trace/events/kmem.h>
-
#include "internal.h"
-
#include "slab.h"

+#define CREATE_TRACE_POINTS
+#include <trace/events/kmem.h>
+
enum slab_state slab_state;
LIST_HEAD(slab_caches);
DEFINE_MUTEX(slab_mutex);
diff --git a/mm/slob.c b/mm/slob.c
index 40ea6e2d4ccd..69875419769c 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -610,14 +610,12 @@ 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_node(_RET_IP_, b, c->object_size,
- SLOB_UNITS(c->size) * SLOB_UNIT,
- flags, node);
+ trace_kmalloc_node(_RET_IP_, b, c->object_size,
+ SLOB_UNITS(c->size) * SLOB_UNIT, flags, node);
} else {
b = slob_new_pages(flags, get_order(c->size), node);
- trace_kmem_cache_alloc_node(_RET_IP_, b, c->object_size,
- PAGE_SIZE << get_order(c->size),
- flags, node);
+ trace_kmalloc_node(_RET_IP_, b, c->object_size,
+ PAGE_SIZE << get_order(c->size), flags, node);
}

if (b && c->ctor) {
diff --git a/mm/slub.c b/mm/slub.c
index ed5c2c03a47a..fc6678269db0 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3231,8 +3231,7 @@ 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->object_size,
- s->size, gfpflags);
+ trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags);

return ret;
}
@@ -3266,8 +3265,7 @@ 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_node(_RET_IP_, ret,
- s->object_size, s->size, gfpflags, node);
+ trace_kmem_cache_alloc_node(_RET_IP_, ret, s, gfpflags, node);

return ret;
}
--
2.31.1