Re: [PATCH v4] tracing: add 'accounted' entry into output of allocation tracepoints

Hyeonggon Yoo
2022-05-22T03:57:07Z

On Sat, May 21, 2022 at 09:36:54PM +0300, Vasily Averin wrote:
> Slab 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 boolean "accounted" entry into trace output,
> and set it to 'true' for calls used __GFP_ACCOUNT flag and
> for allocations from caches marked with SLAB_ACCOUNT.
>
> Signed-off-by: Vasily Averin <vvs@openvz.org>
> Acked-by: Shakeel Butt <shakeelb@google.com>

May I ask what information do you want to collect
using this patch?

I pointed it in another thread but I'm not sure
printing SLAB_* flags in these tracepoint is good :(

If we decide to do that, it would be better to print
something like:
slab_flags=SLAB_RECLAIM_ACCOUNT|SLAB_ACCOUNT|SLAB_STORE_USER
instead of just printing 'accounted=true/false'. This patch is too
specific to SLAB_ACCOUNT.

And if what you want to know is just total slab memory that is accounted,
what about adding something like SlabAccounted in /proc/meminfo?

Thanks.

> ---
> v4:
> 1) replaced in patch descripion: "accounted" instead of "allocated"
> 2) added "Acked-by" from Shakeel,
> 3) re-addressed to akpm@
>
> v3:
> 1) rework kmem_cache_alloc* tracepoints once again,
> added struct kmem_cache argument into existing templates,
> thanks to Matthew Wilcox
> 2) updated according trace_* calls
> 3) added boolean "allocated" entry into trace output,
> thanks to Roman
> 4) updated patch subject and description
>
> v2:
> 1) handle kmem_cache_alloc_node(), thanks to Shakeel
> 2) rework kmem_cache_alloc* tracepoints to use cachep instead
> of current cachep->*size parameters.
> NB: kmem_cache_alloc_node tracepoint in SLOB cannot use cachep,
> and therefore it was replaced by kmalloc_node.
> ---
> include/trace/events/kmem.h | 38 +++++++++++++++++++++++--------------
> mm/slab.c | 10 +++++-----
> mm/slab_common.c | 9 ++++-----
> mm/slob.c | 8 ++++----
> mm/slub.c | 20 +++++++++----------
> 5 files changed, 47 insertions(+), 38 deletions(-)
>
> diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h
> index 71c141804222..5bfeb6f276f1 100644
> --- a/include/trace/events/kmem.h
> +++ b/include/trace/events/kmem.h
> @@ -13,11 +13,12 @@ DECLARE_EVENT_CLASS(kmem_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),
>
> - TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags),
> + TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags),
>
> TP_STRUCT__entry(
> __field( unsigned long, call_site )
> @@ -25,6 +26,7 @@ DECLARE_EVENT_CLASS(kmem_alloc,
> __field( size_t, bytes_req )
> __field( size_t, bytes_alloc )
> __field( unsigned long, gfp_flags )
> + __field( bool, accounted )
> ),
>
> TP_fast_assign(
> @@ -33,42 +35,46 @@ DECLARE_EVENT_CLASS(kmem_alloc,
> __entry->bytes_req = bytes_req;
> __entry->bytes_alloc = bytes_alloc;
> __entry->gfp_flags = (__force unsigned long)gfp_flags;
> + __entry->accounted = (gfp_flags & __GFP_ACCOUNT) ||

I doubt someone will pass __GFP_ACCOUNT in gfpflags
when calling kmem_cache_alloc*().

> + (s && s->flags & SLAB_ACCOUNT);
> ),
>
> - TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s",
> + TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s accounted=%s",
> (void *)__entry->call_site,
> __entry->ptr,
> __entry->bytes_req,
> __entry->bytes_alloc,
> - show_gfp_flags(__entry->gfp_flags))
> + show_gfp_flags(__entry->gfp_flags),
> + __entry->accounted ? "true" : "false")
> );
>
> DEFINE_EVENT(kmem_alloc, kmalloc,
>
> - TP_PROTO(unsigned long call_site, const void *ptr,
> + 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),
>
> - TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags)
> + TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags)
> );
>
> DEFINE_EVENT(kmem_alloc, kmem_cache_alloc,
>
> - TP_PROTO(unsigned long call_site, const void *ptr,
> + 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),
>
> - TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags)
> + TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags)
> );
>
> DECLARE_EVENT_CLASS(kmem_alloc_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_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags, node),
> + TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node),
>
> TP_STRUCT__entry(
> __field( unsigned long, call_site )
> @@ -77,6 +83,7 @@ DECLARE_EVENT_CLASS(kmem_alloc_node,
> __field( size_t, bytes_alloc )
> __field( unsigned long, gfp_flags )
> __field( int, node )
> + __field( bool, accounted )
> ),
>
> TP_fast_assign(
> @@ -86,33 +93,36 @@ DECLARE_EVENT_CLASS(kmem_alloc_node,
> __entry->bytes_alloc = bytes_alloc;
> __entry->gfp_flags = (__force unsigned long)gfp_flags;
> __entry->node = node;
> + __entry->accounted = (gfp_flags & __GFP_ACCOUNT) ||
> + (s && s->flags & SLAB_ACCOUNT);
> ),
>
> - TP_printk("call_site=%pS ptr=%p bytes_req=%zu bytes_alloc=%zu gfp_flags=%s node=%d",
> + 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)
> + __entry->node,
> + __entry->accounted ? "true" : "false")
> );
>
> DEFINE_EVENT(kmem_alloc_node, kmalloc_node,
>
> TP_PROTO(unsigned long call_site, const void *ptr,
> - size_t bytes_req, size_t bytes_alloc,
> + struct kmem_cache *s, size_t bytes_req, size_t bytes_alloc,
> gfp_t gfp_flags, int node),
>
> - TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags, node)
> + TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node)
> );
>
> DEFINE_EVENT(kmem_alloc_node, kmem_cache_alloc_node,
>
> TP_PROTO(unsigned long call_site, const void *ptr,
> - size_t bytes_req, size_t bytes_alloc,
> + struct kmem_cache *s, size_t bytes_req, size_t bytes_alloc,
> gfp_t gfp_flags, int node),
>
> - TP_ARGS(call_site, ptr, bytes_req, bytes_alloc, gfp_flags, node)
> + TP_ARGS(call_site, ptr, s, bytes_req, bytes_alloc, gfp_flags, node)
> );
>
> TRACE_EVENT(kfree,
> diff --git a/mm/slab.c b/mm/slab.c
> index 0edb474edef1..e5802445c7d6 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -3492,7 +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,
> + trace_kmem_cache_alloc(_RET_IP_, ret, cachep,
> cachep->object_size, cachep->size, flags);
>
> return ret;
> @@ -3581,7 +3581,7 @@ kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size)
> ret = slab_alloc(cachep, NULL, flags, size, _RET_IP_);
>
> ret = kasan_kmalloc(cachep, ret, size, flags);
> - trace_kmalloc(_RET_IP_, ret,
> + trace_kmalloc(_RET_IP_, ret, cachep,
> size, cachep->size, flags);
> return ret;
> }
> @@ -3606,7 +3606,7 @@ 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,
> + trace_kmem_cache_alloc_node(_RET_IP_, ret, cachep,
> cachep->object_size, cachep->size,
> flags, nodeid);
>
> @@ -3625,7 +3625,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
> ret = slab_alloc_node(cachep, flags, nodeid, size, _RET_IP_);
>
> ret = kasan_kmalloc(cachep, ret, size, flags);
> - trace_kmalloc_node(_RET_IP_, ret,
> + trace_kmalloc_node(_RET_IP_, ret, cachep,
> size, cachep->size,
> flags, nodeid);
> return ret;
> @@ -3708,7 +3708,7 @@ static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
> ret = slab_alloc(cachep, NULL, flags, size, caller);
>
> ret = kasan_kmalloc(cachep, ret, size, flags);
> - trace_kmalloc(caller, ret,
> + trace_kmalloc(caller, ret, cachep,
> size, cachep->size, flags);
>
> return ret;
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 2b3206a2c3b5..a345e8600e00 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);
> @@ -967,7 +966,7 @@ EXPORT_SYMBOL(kmalloc_order);
> void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
> {
> void *ret = kmalloc_order(size, flags, order);
> - trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
> + trace_kmalloc(_RET_IP_, ret, NULL, size, PAGE_SIZE << order, flags);
> return ret;
> }
> EXPORT_SYMBOL(kmalloc_order_trace);
> diff --git a/mm/slob.c b/mm/slob.c
> index 40ea6e2d4ccd..dbefa0da0dfc 100644
> --- a/mm/slob.c
> +++ b/mm/slob.c
> @@ -505,7 +505,7 @@ __do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller)
> *m = size;
> ret = (void *)m + minalign;
>
> - trace_kmalloc_node(caller, ret,
> + trace_kmalloc_node(caller, ret, NULL,
> size, size + minalign, gfp, node);
> } else {
> unsigned int order = get_order(size);
> @@ -514,7 +514,7 @@ __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_node(caller, ret,
> + trace_kmalloc_node(caller, ret, NULL,
> size, PAGE_SIZE << order, gfp, node);
> }
>
> @@ -610,12 +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,
> + trace_kmem_cache_alloc_node(_RET_IP_, b, NULL, 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,
> + trace_kmem_cache_alloc_node(_RET_IP_, b, NULL, c->object_size,
> PAGE_SIZE << get_order(c->size),
> flags, node);
> }
> diff --git a/mm/slub.c b/mm/slub.c
> index ed5c2c03a47a..9b10591646dd 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -3231,7 +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,
> + trace_kmem_cache_alloc(_RET_IP_, ret, s, s->object_size,
> s->size, gfpflags);
>
> return ret;
> @@ -3254,7 +3254,7 @@ EXPORT_SYMBOL(kmem_cache_alloc_lru);
> void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
> {
> void *ret = slab_alloc(s, NULL, gfpflags, _RET_IP_, size);
> - trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
> + trace_kmalloc(_RET_IP_, ret, s, size, s->size, gfpflags);
> ret = kasan_kmalloc(s, ret, size, gfpflags);
> return ret;
> }
> @@ -3266,7 +3266,7 @@ 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,
> + trace_kmem_cache_alloc_node(_RET_IP_, ret, s,
> s->object_size, s->size, gfpflags, node);
>
> return ret;
> @@ -3280,7 +3280,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
> {
> void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, size);
>
> - trace_kmalloc_node(_RET_IP_, ret,
> + trace_kmalloc_node(_RET_IP_, ret, s,
> size, s->size, gfpflags, node);
>
> ret = kasan_kmalloc(s, ret, size, gfpflags);
> @@ -4409,7 +4409,7 @@ void *__kmalloc(size_t size, gfp_t flags)
>
> ret = slab_alloc(s, NULL, flags, _RET_IP_, size);
>
> - trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
> + trace_kmalloc(_RET_IP_, ret, s, size, s->size, flags);
>
> ret = kasan_kmalloc(s, ret, size, flags);
>
> @@ -4443,7 +4443,7 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
> if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
> ret = kmalloc_large_node(size, flags, node);
>
> - trace_kmalloc_node(_RET_IP_, ret,
> + trace_kmalloc_node(_RET_IP_, ret, NULL,
> size, PAGE_SIZE << get_order(size),
> flags, node);
>
> @@ -4457,7 +4457,7 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
>
> ret = slab_alloc_node(s, NULL, flags, node, _RET_IP_, size);
>
> - trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
> + trace_kmalloc_node(_RET_IP_, ret, s, size, s->size, flags, node);
>
> ret = kasan_kmalloc(s, ret, size, flags);
>
> @@ -4916,7 +4916,7 @@ void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
> ret = slab_alloc(s, NULL, gfpflags, caller, size);
>
> /* Honor the call site pointer we received. */
> - trace_kmalloc(caller, ret, size, s->size, gfpflags);
> + trace_kmalloc(caller, ret, s, size, s->size, gfpflags);
>
> return ret;
> }
> @@ -4932,7 +4932,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
> if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
> ret = kmalloc_large_node(size, gfpflags, node);
>
> - trace_kmalloc_node(caller, ret,
> + trace_kmalloc_node(caller, ret, NULL,
> size, PAGE_SIZE << get_order(size),
> gfpflags, node);
>
> @@ -4947,7 +4947,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
> ret = slab_alloc_node(s, NULL, gfpflags, node, caller, size);
>
> /* Honor the call site pointer we received. */
> - trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
> + trace_kmalloc_node(caller, ret, s, size, s->size, gfpflags, node);
>
> return ret;
> }
> --
> 2.31.1
>