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Message-ID: <YoOOI1Gw2mX9c8qZ@hyeyoo>
Date: Tue, 17 May 2022 20:59:31 +0900
From: Hyeonggon Yoo <42.hyeyoo@...il.com>
To: YoMccU66auLAPEHa@...per.infradead.org
Cc: Steven Rostedt <rostedt@...dmis.org>,
Shakeel Butt <shakeelb@...gle.com>,
Roman Gushchin <roman.gushchin@...ux.dev>,
Vlastimil Babka <vbabka@...e.cz>,
Matthew Wilcox <willy@...radead.org>, kernel@...nvz.org,
linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
Joonsoo Kim <iamjoonsoo.kim@....com>,
David Rientjes <rientjes@...gle.com>,
Pekka Enberg <penberg@...nel.org>,
Christoph Lameter <cl@...ux.com>,
Michal Hocko <mhocko@...e.com>
Subject: Re: [PATCH v2] tracing: add ACCOUNT flag for allocations from marked
slab caches
On Tue, May 17, 2022 at 12:44:14PM +0300, Vasily Averin wrote:
> 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@...nvz.org>
> ---
> 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);
> + ),
This is a bit of lie. SLAB_ACCOUNT is not a gfp flag.
IMO the problem here is that we don't know which cache kernel is allocating
from. What about just printing name of cache and remove bytes_req,
bytes_alloc?
And then you can check if the cache uses SLAB_ACCOUNT or not.
>
> - 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
>
>
--
Thanks,
Hyeonggon
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