On Sun, Sep 29, 2024 at 10:04:00AM -0700, Alexei Starovoitov wrote: > On Fri, Sep 27, 2024 at 11:41 AM Namhyung Kim <namhyung@xxxxxxxxxx> wrote: > > +static void *kmem_cache_iter_seq_start(struct seq_file *seq, loff_t *pos) > > +{ > > + loff_t cnt = 0; > > + struct kmem_cache *s = NULL; > > + > > + mutex_lock(&slab_mutex); > > It would be better to find a way to iterate slabs without holding > the mutex for the duration of the loop. > Maybe use refcnt to hold the kmem_cache while bpf prog is looking at it? Do you mean that you want to not hold slab_mutex while BPF program is running? Maybe we can allocates an arary of pointers to the slab cahe (with refcounts) at the beginning and iterate them instead. And call kmem_cache_destroy() for each entry at the end. Is it ok to you? Thanks, Namhyung