lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <YzCYXEytXy8UJQFv@yury-laptop> Date: Sun, 25 Sep 2022 11:05:16 -0700 From: Yury Norov <yury.norov@...il.com> To: Valentin Schneider <vschneid@...hat.com> Cc: netdev@...r.kernel.org, linux-rdma@...r.kernel.org, linux-kernel@...r.kernel.org, Saeed Mahameed <saeedm@...dia.com>, Leon Romanovsky <leon@...nel.org>, "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, Rasmus Villemoes <linux@...musvillemoes.dk>, Ingo Molnar <mingo@...nel.org>, Peter Zijlstra <peterz@...radead.org>, Vincent Guittot <vincent.guittot@...aro.org>, Dietmar Eggemann <dietmar.eggemann@....com>, Steven Rostedt <rostedt@...dmis.org>, Mel Gorman <mgorman@...e.de>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Heiko Carstens <hca@...ux.ibm.com>, Tony Luck <tony.luck@...el.com>, Jonathan Cameron <Jonathan.Cameron@...wei.com>, Gal Pressman <gal@...dia.com>, Tariq Toukan <tariqt@...dia.com>, Jesse Brandeburg <jesse.brandeburg@...el.com> Subject: Re: [PATCH v4 5/7] sched/topology: Introduce sched_numa_hop_mask() On Fri, Sep 23, 2022 at 04:55:40PM +0100, Valentin Schneider wrote: > Tariq has pointed out that drivers allocating IRQ vectors would benefit > from having smarter NUMA-awareness - cpumask_local_spread() only knows > about the local node and everything outside is in the same bucket. > > sched_domains_numa_masks is pretty much what we want to hand out (a cpumask > of CPUs reachable within a given distance budget), introduce > sched_numa_hop_mask() to export those cpumasks. > > Link: http://lore.kernel.org/r/20220728191203.4055-1-tariqt@nvidia.com > Signed-off-by: Valentin Schneider <vschneid@...hat.com> > --- > include/linux/topology.h | 12 ++++++++++++ > kernel/sched/topology.c | 31 +++++++++++++++++++++++++++++++ > 2 files changed, 43 insertions(+) > > diff --git a/include/linux/topology.h b/include/linux/topology.h > index 4564faafd0e1..3e91ae6d0ad5 100644 > --- a/include/linux/topology.h > +++ b/include/linux/topology.h > @@ -245,5 +245,17 @@ static inline const struct cpumask *cpu_cpu_mask(int cpu) > return cpumask_of_node(cpu_to_node(cpu)); > } > > +#ifdef CONFIG_NUMA > +extern const struct cpumask *sched_numa_hop_mask(int node, int hops); > +#else > +static inline const struct cpumask *sched_numa_hop_mask(int node, int hops) > +{ > + if (node == NUMA_NO_NODE && !hops) > + return cpu_online_mask; > + > + return ERR_PTR(-EOPNOTSUPP); > +} > +#endif /* CONFIG_NUMA */ > + > > #endif /* _LINUX_TOPOLOGY_H */ > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c > index 8739c2a5a54e..ee77706603c0 100644 > --- a/kernel/sched/topology.c > +++ b/kernel/sched/topology.c > @@ -2067,6 +2067,37 @@ int sched_numa_find_closest(const struct cpumask *cpus, int cpu) > return found; > } > > +/** > + * sched_numa_hop_mask() - Get the cpumask of CPUs at most @hops hops away. > + * @node: The node to count hops from. > + * @hops: Include CPUs up to that many hops away. 0 means local node. > + * > + * Requires rcu_lock to be held. Returned cpumask is only valid within that > + * read-side section, copy it if required beyond that. > + * > + * Note that not all hops are equal in distance; see sched_init_numa() for how > + * distances and masks are handled. > + * > + * Also note that this is a reflection of sched_domains_numa_masks, which may change > + * during the lifetime of the system (offline nodes are taken out of the masks). > + */ > +const struct cpumask *sched_numa_hop_mask(int node, int hops) > +{ > + struct cpumask ***masks = rcu_dereference(sched_domains_numa_masks); > + > + if (node == NUMA_NO_NODE && !hops) > + return cpu_online_mask; > + > + if (node >= nr_node_ids || hops >= sched_domains_numa_levels) > + return ERR_PTR(-EINVAL); This looks like a sanity check. If so, it should go before the snippet above, so that client code would behave consistently. > + > + if (!masks) > + return NULL; In (node == NUMA_NO_NODE && !hops) case you return online cpus. Here you return NULL just to convert it to cpu_online_mask in the caller. This looks inconsistent. So, together with the above comment, this makes me feel that you'd do it like this: const struct cpumask *sched_numa_hop_mask(int node, int hops) { struct cpumask ***masks; if (node >= nr_node_ids || hops >= sched_domains_numa_levels) { #ifdef CONFIG_SCHED_DEBUG pr_err(...); #endif return ERR_PTR(-EINVAL); } if (node == NUMA_NO_NODE && !hops) return cpu_online_mask; /* or NULL */ masks = rcu_dereference(sched_domains_numa_masks); if (!masks) return cpu_online_mask; /* or NULL */ return masks[hops][node]; }
Powered by blists - more mailing lists