On Fri, Feb 25, 2022 at 07:03:14PM +0100, Vlastimil Babka wrote:
> set_track() either zeroes out the struct track or fills it, depending on
> the addr parameter. This is unnecessary as there's only one place that
> calls it for the initialization - init_tracking(). We can simply do the
> zeroing there, with a single memset() that covers both TRACK_ALLOC and
> TRACK_FREE as they are adjacent.
>
> Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
> ---
> mm/slub.c | 32 +++++++++++++++-----------------
> 1 file changed, 15 insertions(+), 17 deletions(-)
>
> diff --git a/mm/slub.c b/mm/slub.c
> index 261474092e43..1fc451f4fe62 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -729,34 +729,32 @@ static void set_track(struct kmem_cache *s, void *object,
> {
> struct track *p = get_track(s, object, alloc);
>
> - if (addr) {
> #ifdef CONFIG_STACKTRACE
> - unsigned int nr_entries;
> + unsigned int nr_entries;
>
> - metadata_access_enable();
> - nr_entries = stack_trace_save(kasan_reset_tag(p->addrs),
> - TRACK_ADDRS_COUNT, 3);
> - metadata_access_disable();
> + metadata_access_enable();
> + nr_entries = stack_trace_save(kasan_reset_tag(p->addrs),
> + TRACK_ADDRS_COUNT, 3);
> + metadata_access_disable();
>
> - if (nr_entries < TRACK_ADDRS_COUNT)
> - p->addrs[nr_entries] = 0;
> + if (nr_entries < TRACK_ADDRS_COUNT)
> + p->addrs[nr_entries] = 0;
> #endif
> - p->addr = addr;
> - p->cpu = smp_processor_id();
> - p->pid = current->pid;
> - p->when = jiffies;
> - } else {
> - memset(p, 0, sizeof(struct track));
> - }
> + p->addr = addr;
> + p->cpu = smp_processor_id();
> + p->pid = current->pid;
> + p->when = jiffies;
> }
>
> static void init_tracking(struct kmem_cache *s, void *object)
> {
> + struct track *p;
> +
> if (!(s->flags & SLAB_STORE_USER))
> return;
>
> - set_track(s, object, TRACK_FREE, 0UL);
> - set_track(s, object, TRACK_ALLOC, 0UL);
> + p = get_track(s, object, TRACK_ALLOC);
> + memset(p, 0, 2*sizeof(struct track));
> }
>
Looks good.
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
And works nicely.
Tested-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
> static void print_track(const char *s, struct track *t, unsigned long pr_time)
> --
> 2.35.1
>
>
--
Thank you, You are awesome!
Hyeonggon :-)
