On Mon, Oct 19, 2015 at 03:10:46PM +0800, yalin wang wrote: > This patch change map_lookup_elem() and map_update_elem() function > to use u64 temp variable if the key_size or value_size is less than > u64, we don't need use kmalloc() for these small variables. > > Signed-off-by: yalin wang <yalin.wang2...@gmail.com> > --- > kernel/bpf/syscall.c | 30 ++++++++++++++++++++---------- > 1 file changed, 20 insertions(+), 10 deletions(-) > > diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c > index f640e5f..c82d7bf 100644 > --- a/kernel/bpf/syscall.c > +++ b/kernel/bpf/syscall.c > @@ -189,7 +189,8 @@ static int map_lookup_elem(union bpf_attr *attr) > void __user *uvalue = u64_to_ptr(attr->value); > int ufd = attr->map_fd; > struct bpf_map *map; > - void *key, *value, *ptr; > + u64 key_buf, value_buf; > + void *key = &key_buf, *value = &value_buf, *ptr; > struct fd f; > int err; > > @@ -202,7 +203,8 @@ static int map_lookup_elem(union bpf_attr *attr) > return PTR_ERR(map); > > err = -ENOMEM; > - key = kmalloc(map->key_size, GFP_USER); > + if (map->key_size > sizeof(u64)) > + key = kmalloc(map->key_size, GFP_USER);
I think it's a good optimization for common case. Performance numbers would be good to prove the point. Thanks -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
