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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?0dwX9d1Z7RRO6ktl2GCW/mTCqt/f4Zg+S1Xqn5i5Uw81lYUcuYoHU5BmzBs7?= =?us-ascii?Q?6hvfroZmYef5dzdI81nNRzWSnoX+oX/edoY2MPYbbEDs8nhw7/co6GD2/UVw?= =?us-ascii?Q?krx5GWmQNIfYXvQxgp9BXls5SE89rILp+hRpLim9CaXQ465+JEzHQjUNgq+5?= =?us-ascii?Q?NmWudfpg/aS9vYG9gAcf36QVP6N3xiDxRMhLF2ie3aFWcEAgMBl4j1lNU2bz?= =?us-ascii?Q?Z6KN7FPyRWMdxrHM66AN+nZt8N0kfRJdGCXUwCa3LPaA5Tc9vs3jwi3owalQ?= =?us-ascii?Q?XAcWkj/93MjVjj72M9iIJAOJ8QhI79XPljKPN5a8DmKHRSSml12rvhmKNt8k?= =?us-ascii?Q?8bjPaYSf52V7jrXIPatkWGEgJKeTUjnMWIWmP3TJhdb3nAqArwfvAKS85oID?= =?us-ascii?Q?vQiFTt6L8TGy/TUIo7ey+USFeNxo5JhNnrCMzyjn8Vw8kI5q+FK+lqUaqbtv?= =?us-ascii?Q?TxKBix9/0Db+XDAQaZB94bb3T7DNytRUWwahjVVsI6WEQhnlRsj7Ot5Zns1s?= =?us-ascii?Q?tFMEvCbQIZa5gZw0fFQXhQCrnOM0bLCCU71Za3CdUj8XNkOuS4fEr43bbsWC?= =?us-ascii?Q?vIKpDNb1oXKh/2aZub0U6Zm3yXfBtf9Yx+DhCUDJiRUXW4rk9qTSpHezRNEf?= =?us-ascii?Q?VFRG24V7HrLIzrP6xxRn4R5YLzQNHTyAB0+Boc+Hv7w0jms92ueT/PfdfWxg?= =?us-ascii?Q?wpKKJEIzq0zcI1qz4IqkQYL80X/9NsvuF3DSyb/8RLEnbNiBcsF0tY6xldv0?= =?us-ascii?Q?dZJf9YpG8S4MOjZq44R4PV5BVYbGoUNwvDRZRAG0txtvGQ4ZYj/e71M2TcnL?= =?us-ascii?Q?d9g5yOdzYsy7ZGpgHUw1pLrVjKAXctP533ZgM8FZMt30PToV8KtcZlXWuwuw?= =?us-ascii?Q?D/0lgzTZoAw3kUeUO1mbAO62kZYWqftA2/rlYseCeWqwpk9rZD47bpp+7C2o?= =?us-ascii?Q?DFmJIod5gqPTQdSxXZd2tc/cyD93cJVYYpVtmDH7PvX6GOVtGe3yw3WSs7D+?= =?us-ascii?Q?T4ogSNDBzskIMkZkdyYMbXAkBKwO1iMovoY3re0cz5DTa+BYFjfecOYrl4cB?= =?us-ascii?Q?rcisKLgXhgtallGi+VRV1PU8lN3kLt9S6kRvNgjLVSeM4riT7qpsK//YJWSI?= =?us-ascii?Q?YBYUXKdwavhmp+bYDbpcvgruKqDLu95Ydd165X1Pow1a3Xk9n0dnsWh393gk?= =?us-ascii?Q?ktjW6SQA6DJftljF5mpkYbuXWv5fYMTo9IZf4DbBkvjmJXAxwQ8M5VuyrqD/?= =?us-ascii?Q?CNgz/NtsuW8J6Ul6riNKOQ663vsBj1bsNUwb+TGcGUUewCFfiRzPHjn16QSL?= =?us-ascii?Q?Pplmn/d+fdrQSDm/oxhF4o4DSgovDU20XjWbWi84Vr9+nWsjsfRKqmp5R8Zp?= =?us-ascii?Q?WGGuEm8ZgUwHB1P1oD4j91vaibZ53mC5tzSEGPq2TDAP6hgv3sLOaIj/OH6l?= =?us-ascii?Q?KZ2MAVTCXNCBOWEi/5dyHmcDhpqEWuKd5Pegsc9IKNfpJmA+GV9fpWnk4A87?= =?us-ascii?Q?M0miDya3yNyMtc3obV28HuOOW+E+4vXwKJMkxnGkEIt5ChDnu7WUZuH7T0VX?= =?us-ascii?Q?nm1hjCHYvKJpcY7uIWuJhZgMROLocBwcm5DaT9Vx?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: bc448a19-3e43-456d-1723-08dd4821b89e X-MS-Exchange-CrossTenant-AuthSource: CY5PR12MB6405.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 08 Feb 2025 09:19:42.6251 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: dxDisZYHfigiESBqZ0ao73rGK6JgkNaohyTycMYKe9Kug7MPW/xS9sNiyOdm9HMDgruwA2a2zy4jClyuiriDOQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: IA0PR12MB8277 On Fri, Feb 07, 2025 at 12:39:57PM -1000, Tejun Heo wrote: > Hello, > > On Fri, Feb 07, 2025 at 09:40:53PM +0100, Andrea Righi wrote: > > +/** > > + * scx_bpf_cpu_to_node - Return the NUMA node the given @cpu belongs to > > + */ > > +__bpf_kfunc int scx_bpf_cpu_to_node(s32 cpu) > > Maybe scx_bpf_cpu_node() to be in line with scx_bpf_task_cpu/cgroup()? Ok, then maybe we can have scx_bpf_cpu_node() for the kfunc, that wraps scx_cpu_node() for internal use. > > > +{ > > +#ifdef CONFIG_NUMA > > + if (cpu < 0 || cpu >= nr_cpu_ids) > > + return -EINVAL; > > Use ops_cpu_valid()? Otherwise, we can end up calling cpu_to_node() with an > impossible CPU. Also, I don't think CPU -> node mapping function should be > able to return an error value. It should just trigger ops error. Ok. > > > + > > + return idle_cpu_to_node(cpu); > > This is contingent on scx_builtin_idle_per_node, right? It's confusing for > CPU -> node mapping function to return NUMA_NO_NODE depending on an ops > flag. Shouldn't this be a generic mapping function? The idea is that BPF schedulers can use this kfunc to determine the right idle cpumask to use, for example a typical usage could be: int node = scx_bpf_cpu_node(prev_cpu); s32 cpu = scx_bpf_pick_idle_cpu_in_node(p->cpus_ptr, node, SCX_PICK_IDLE_IN_NODE); Or: int node = scx_bpf_cpu_node(prev_cpu); const struct cpumask *idle_cpumask = scx_bpf_get_idle_cpumask_node(node); When SCX_OPS_BUILTIN_IDLE_PER_NODE is disabled, we need to point to the global idle cpumask, that is identified by NUMA_NO_NODE, so this is why we can return NUMA_NO_NODE fro scx_bpf_cpu_node(). Do you think we should make this more clear / document this better. Or do you think we should use a different API? > > > index 50e1499ae0935..caa1a80f9a60c 100644 > > --- a/tools/sched_ext/include/scx/compat.bpf.h > > +++ b/tools/sched_ext/include/scx/compat.bpf.h > > @@ -130,6 +130,25 @@ bool scx_bpf_dispatch_vtime_from_dsq___compat(struct bpf_iter_scx_dsq *it__iter, > > scx_bpf_now() : \ > > bpf_ktime_get_ns()) > > > > +#define __COMPAT_scx_bpf_cpu_to_node(cpu) \ > > + (bpf_ksym_exists(scx_bpf_cpu_to_node) ? \ > > + scx_bpf_cpu_to_node(cpu) : 0) > > + > > +#define __COMPAT_scx_bpf_get_idle_cpumask_node(node) \ > > + (bpf_ksym_exists(scx_bpf_get_idle_cpumask_node) ? \ > > + scx_bpf_get_idle_cpumask_node(node) : \ > > + scx_bpf_get_idle_cpumask()) \ > > + > > +#define __COMPAT_scx_bpf_get_idle_smtmask_node(node) \ > > + (bpf_ksym_exists(scx_bpf_get_idle_smtmask_node) ? \ > > + scx_bpf_get_idle_smtmask_node(node) : \ > > + scx_bpf_get_idle_smtmask()) > > + > > +#define __COMPAT_scx_bpf_pick_idle_cpu_node(cpus_allowed, node, flags) \ > > + (bpf_ksym_exists(scx_bpf_pick_idle_cpu_node) ? \ > > + scx_bpf_pick_idle_cpu_node(cpus_allowed, node, flags) : \ > > + scx_bpf_pick_idle_cpu(cpus_allowed, flags)) > > Can you please document when these compat macros can be dropped? Also, > shouldn't it also provide a compat macro for the new ops flag using > __COMPAT_ENUM_OR_ZERO()? Otherwise, trying to load new binary using the new > flag on an older kernel will fail, right? Right. Will add that. Thanks, -Andrea