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Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.11.0 Subject: Re: [PATCH 14/16] mm/slab_common: drop kmem_alloc & avoid dereferencing fields when not using Content-Language: en-US To: Hyeonggon Yoo <42.hyeyoo@gmail.com>, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin , Joe Perches , Vasily Averin , Matthew WilCox Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20220712133946.307181-1-42.hyeyoo@gmail.com> <20220712133946.307181-15-42.hyeyoo@gmail.com> From: Vlastimil Babka In-Reply-To: <20220712133946.307181-15-42.hyeyoo@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1659093820; a=rsa-sha256; cv=none; b=nU1GCAGHyK8LJ8198azwzGkyTRv2nMtaKnEGWNaMGPpRL1i7lYob522M8dSvcSwUHBHpdx qox6je+L+xvz3AMw4BK3w1UOcRD+mUA0stvzOPAdJLIa9EpfE/+OxYJ77e586FM+odYHzg 0FpgG3N1Eey9Ql9APiDklEpwtufVU4k= ARC-Authentication-Results: i=1; imf03.hostedemail.com; 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spf=pass (imf03.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 475B2200AE X-Stat-Signature: q76k64dtgpq3rzqjqex1g8j9t8qktkbb X-HE-Tag: 1659093820-25534 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 7/12/22 15:39, Hyeonggon Yoo wrote: > 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. > > Suggested-by: Vlastimil Babka > Signed-off-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Reviewed-by: Vlastimil Babka With some comments: > --- > include/trace/events/kmem.h | 64 +++++++++++++++++++++++++------------ > mm/slab.c | 16 ++++------ > mm/slab_common.c | 17 ++++++---- > mm/slob.c | 16 +++------- > mm/slub.c | 13 +++----- > 5 files changed, 70 insertions(+), 56 deletions(-) > > diff --git a/include/trace/events/kmem.h b/include/trace/events/kmem.h > index e078ebcdc4b1..0ded2c351062 100644 > --- a/include/trace/events/kmem.h > +++ b/include/trace/events/kmem.h > @@ -9,17 +9,15 @@ > #include > #include > > -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 ) > @@ -34,8 +32,8 @@ 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) ? This assignment continues by ... (s && s->flags & SLAB_ACCOUNT)) : false; We could now remove the "s &&" as we assume it's non-NULL anyway. > @@ -53,22 +51,46 @@ 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 ) > + __field( bool, accounted ) > + ), > > - 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; > + __entry->accounted = IS_ENABLED(CONFIG_MEMCG_KMEM) ? > + (gfp_flags & __GFP_ACCOUNT) : false; This test could be perhaps moved to TP_printk and the accounted field removed completely, but we need to make sure trace-cmd (which reads the binary entries and does the printk in userspace) can interpret the tests properly, including the IS_ENABLED(CONFIG_MEMCG_KMEM) part. > + ), > > - 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, > + __entry->accounted ? "true" : "false") > ); > > TRACE_EVENT(kfree, > @@ -93,20 +115,20 @@ 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 f9b74831e3f4..1685e5507a59 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -3447,8 +3447,7 @@ 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; > } > @@ -3537,8 +3536,9 @@ 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, cachep, > - size, cachep->size, flags, NUMA_NO_NODE); > + trace_kmalloc(_RET_IP_, ret, > + size, cachep->size, > + flags, NUMA_NO_NODE); This could now fit on 2, maybe even 1 line? Other trace_* calls could be perhaps also reduced, please check. > return ret; > } > EXPORT_SYMBOL(kmem_cache_alloc_trace); > @@ -3561,9 +3561,7 @@ 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; > } > @@ -3588,7 +3586,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep, > ret = slab_alloc_node(cachep, NULL, flags, nodeid, size, _RET_IP_); > > ret = kasan_kmalloc(cachep, ret, size, flags); > - trace_kmalloc(_RET_IP_, ret, cachep, > + trace_kmalloc(_RET_IP_, ret, > size, cachep->size, > flags, nodeid); > return ret; > @@ -3652,7 +3650,7 @@ 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 0e66b4911ebf..c01c6b8f0d34 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -933,7 +933,7 @@ 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_notrace(size, flags, node); > - trace_kmalloc(_RET_IP_, ret, NULL, > + trace_kmalloc(_RET_IP_, ret, > size, PAGE_SIZE << get_order(size), > flags, node); > return ret; > @@ -946,8 +946,9 @@ 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; > } > > @@ -1075,8 +1076,9 @@ void *kmalloc_large(size_t size, gfp_t flags) > { > void *ret = __kmalloc_large_node_notrace(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); > @@ -1090,8 +1092,9 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node) > { > void *ret = __kmalloc_large_node_notrace(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 a4d50d957c25..97a4d2407f96 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); > @@ -608,14 +606,10 @@ 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, Hm we lose the SLOB_UNITS() adjustment here. Maybe we don't care that much, maybe simply c->size could be already stored with SLOB_UNITS() (but didn't check if other stuff breaks with that). Thanks! > - 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 +665,7 @@ 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 f1aa51480dc4..a49c69469c64 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; > } > @@ -3274,7 +3273,7 @@ void *__kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, > 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, 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; > } > @@ -3285,8 +3284,7 @@ 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; > } > @@ -3299,8 +3297,7 @@ void *kmem_cache_alloc_node_trace(struct kmem_cache *s, > { > void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, size); > > - trace_kmalloc(_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; > @@ -3544,7 +3541,7 @@ 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);