On 07.03.22 16:07, Oscar Salvador wrote:
> Since we pre-allocate all nodes now, hotadd_init_pgdat() does
> not need to return a pgdat struct, as that was meant for
> __try_online_node() to check whether the node was succesfully
> allocated.
>
> Also get rid of the __ref as all functions hotadd_init_pgdat()
> calls fall within the same section.
>
> Also try to make more clear the return codes from __try_online_node().
> __try_online_node() can return either 0, 1 or -errno (the latter not really
> as the BUG_ON() would catch it before we return) but depending on the caller
> that has different meanings.
> For add_memory_resource(), when __try_online_node() returns non-zero,
> it means that the node was already allocated and it does not need to bring
> it up. It is fine not to check for -errno values because we do not
> get to call register_one_node() when !set_node_online.
> For those who call try_online_node(), so set_node_online is true, a value
> other than zero means a failure (e.g: cpu_up() or find_and_online_cpu_nid()).
>
> Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
> ---
> mm/memory_hotplug.c | 35 ++++++++++++++---------------------
> 1 file changed, 14 insertions(+), 21 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 07cece9e22e4..5c92ac81a399 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1161,8 +1161,7 @@ static void reset_node_present_pages(pg_data_t *pgdat)
> pgdat->node_present_pages = 0;
> }
>
> -/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
> -static pg_data_t __ref *hotadd_init_pgdat(int nid)
> +static void hotadd_init_pgdat(int nid)
> {
> struct pglist_data *pgdat = NODE_DATA(nid);
>
> @@ -1182,8 +1181,6 @@ static pg_data_t __ref *hotadd_init_pgdat(int nid)
> * to access not-initialized zonelist, build here.
> */
> build_all_zonelists(pgdat);
> -
> - return pgdat;
> }
>
> /*
> @@ -1193,31 +1190,27 @@ static pg_data_t __ref *hotadd_init_pgdat(int nid)
> * called by cpu_up() to online a node without onlined memory.
> *
> * Returns:
> - * 1 -> a new node has been allocated
> - * 0 -> the node is already online
> - * -ENOMEM -> the node could not be allocated
> + * 1 -> The node has been initialized.
> + * 0 -> Either the node was already online, or we succesfully registered a new
> + * one.
> + * -errno -> register_one_node() failed.
> */
> static int __try_online_node(int nid, bool set_node_online)
> {
> - pg_data_t *pgdat;
> - int ret = 1;
> + int ret;
>
> if (node_online(nid))
> return 0;
>
> - pgdat = hotadd_init_pgdat(nid);
> - if (!pgdat) {
> - pr_err("Cannot online node %d due to NULL pgdat\n", nid);
> - ret = -ENOMEM;
> - goto out;
> - }
> + hotadd_init_pgdat(nid);
> +
> + if (!set_node_online)
> + return 1;
> +
> + node_set_online(nid);
> + ret = register_one_node(nid);
> + BUG_ON(ret);
>
> - if (set_node_online) {
> - node_set_online(nid);
> - ret = register_one_node(nid);
> - BUG_ON(ret);
> - }
> -out:
> return ret;
BUG_ON(ret);
return ret;
hm? This will never return :)
So either leave the old code flow or "return 1;" I'd actually prefer the
old code flow to then "return 1;" here:
if (set_node_online) {
node_set_online(nid);
BUG_ON(register_one_node(nid));
}
return 1;
We can then let go of "ret".
--
Thanks,
David / dhildenb
