On Sat, Oct 30, 2021 at 6:12 PM Yunfeng Ye <yeyunfeng@xxxxxxxxxx> wrote: > > After the memory is freed, it may be allocated by other CPUs and has > been recorded by trace. So the timing sequence of the memory tracing is > inaccurate. > > For example, we expect the following timing sequeuce: > > CPU 0 CPU 1 > > (1) alloc xxxxxx > (2) free xxxxxx > (3) alloc xxxxxx > (4) free xxxxxx > > However, the following timing sequence may occur: > > CPU 0 CPU 1 > > (1) alloc xxxxxx > (2) alloc xxxxxx > (3) free xxxxxx > (4) free xxxxxx > > So place the trace before freeing memory in kmem_cache_free(). Could you tell me what problem you have encountered here? Thanks. > > Signed-off-by: Yunfeng Ye <yeyunfeng@xxxxxxxxxx> > --- > mm/slub.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/slub.c b/mm/slub.c > index 432145d7b4ec..427e62034c3f 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -3526,8 +3526,8 @@ void kmem_cache_free(struct kmem_cache *s, void *x) > s = cache_from_obj(s, x); > if (!s) > return; > - slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_); > trace_kmem_cache_free(_RET_IP_, x, s->name); > + slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_); > } > EXPORT_SYMBOL(kmem_cache_free); > > -- > 2.27.0
