On Tue, Jul 27, 2021 at 09:02:33AM +0530, Aneesh Kumar K.V wrote: > David Gibson writes: > > > On Thu, Jul 22, 2021 at 12:37:46PM +0530, Aneesh Kumar K.V wrote: > >> David Gibson writes: > >> > >> > On Mon, Jun 28, 2021 at 08:41:15PM +0530, Aneesh Kumar K.V wrote: > > .... > > > > >> > > >> >> + nid = of_read_number(&aa.arrays[index], 1); > >> >> + > >> >> + if (nid == 0xffff || nid >= nr_node_ids) > >> >> + nid = default_nid; > >> >> + if (nid > 0 && affinity_form == FORM1_AFFINITY) { > >> >> + int i; > >> >> + const __be32 *associativity; > >> >> + > >> >> + index = lmb->aa_index * aa.array_sz; > >> >> + associativity = &aa.arrays[index]; > >> >> + /* > >> >> + * lookup array associativity entries have different format > >> >> + * There is no length of the array as the first element. > >> > > >> > The difference it very small, and this is not a hot path. Couldn't > >> > you reduce a chunk of code by prepending aa.array_sz, then re-using > >> > __initialize_form1_numa_distance. Or even making > >> > __initialize_form1_numa_distance() take the length as a parameter. > >> > >> The changes are small but confusing w.r.t how we look at the > >> associativity-lookup-arrays. The way we interpret associativity array > >> and associativity lookup array using primary_domain_index is different. > >> Hence the '-1' in the node lookup here. > > > > They're really not, though. It's exactly the same interpretation of > > the associativity array itself - it's just that one of them has the > > array prepended with a (redundant) length. So you can make > > __initialize_form1_numa_distance() work on the "bare" associativity > > array, with a given length. Here you call it with aa.array_sz as the > > length, and in the other place you call it with prop[0] as the length. > > > >> > >> index = lmb->aa_index * aa.array_sz + primary_domain_index - 1; > >> nid = of_read_number(&aa.arrays[index], 1); > >> > >> > >> > > >> >> + */ > >> >> + for (i = 0; i < max_associativity_domain_index; i++) { > >> >> + const __be32 *entry; > >> >> + > >> >> + entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1]; > >> > > >> > Does anywhere verify that distance_ref_points[i] <= aa.array_size for > >> > every i? > >> > >> We do check for > >> > >> if (primary_domain_index <= aa.array_sz && > > > > Right, but that doesn't check the other distance_ref_points entries. > > Not that there's any reason to have extra entries with Form2, but we > > still don't want stray array accesses. > > This is how the change looks. I am not convinced this makes it simpler. It's not, but that's because the lookup_array_assoc flag is not needed... > I will add that as the last patch and we can drop that if we find that > not helpful? > > modified arch/powerpc/mm/numa.c > @@ -171,20 +171,31 @@ static void unmap_cpu_from_node(unsigned long cpu) > } > #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */ > > -/* > - * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA > - * info is found. > - */ > -static int associativity_to_nid(const __be32 *associativity) > +static int __associativity_to_nid(const __be32 *associativity, > + bool lookup_array_assoc, > + int max_array_index) > { > int nid = NUMA_NO_NODE; > + int index; > > if (!numa_enabled) > goto out; > + /* > + * ibm,associativity-lookup-array doesn't have element > + * count at the start of the associativity. Hence > + * decrement the primary_domain_index when used with > + * lookup-array associativity. > + */ > + if (lookup_array_assoc) > + index = primary_domain_index - 1; > + else { > + index = primary_domain_index; > + max_array_index = of_read_number(associativity, 1); > + } > + if (index > max_array_index) > + goto out; So, the associativity-array-with-length is exactly a length, followed by an associativity-array-without-length. What I was suggesting is you make this function only take an associativity-array-without-length, with the length passed separately. Where you want to use it on an associativity-array-with-length, stored in __be32 *awl, you just invoke it as: associativity_to_nid(awl + 1, of_read_number(awl, 1)); > - if (of_read_number(associativity, 1) >= primary_domain_index) > - nid = of_read_number(&associativity[primary_domain_index], 1); > - > + nid = of_read_number(&associativity[index], 1); > /* POWER4 LPAR uses 0xffff as invalid node */ > if (nid == 0xffff || nid >= nr_node_ids) > nid = NUMA_NO_NODE; > @@ -192,6 +203,15 @@ static int associativity_to_nid(const __be32 *associativity) > return nid; > } > > +/* > + * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA > + * info is found. > + */ > +static inline int associativity_to_nid(const __be32 *associativity) > +{ > + return __associativity_to_nid(associativity, false, 0); > +} > + > static int __cpu_form2_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc) > { > int dist; > @@ -295,19 +315,38 @@ int of_node_to_nid(struct device_node *device) > } > EXPORT_SYMBOL(of_node_to_nid); > > -static void __initialize_form1_numa_distance(const __be32 *associativity) > +static void __initialize_form1_numa_distance(const __be32 *associativity, > + bool lookup_array_assoc, > + int max_array_index) > { > int i, nid; > + int index_offset = 0; > > if (affinity_form != FORM1_AFFINITY) > return; > + /* > + * ibm,associativity-lookup-array doesn't have element > + * count at the start of the associativity. Hence > + * decrement the distance_ref_points index when used with > + * lookup-array associativity. > + */ > + if (lookup_array_assoc) > + index_offset = 1; > + else > + max_array_index = of_read_number(associativity, 1); > > - nid = associativity_to_nid(associativity); > + nid = __associativity_to_nid(associativity, lookup_array_assoc, max_array_index); > if (nid != NUMA_NO_NODE) { > for (i = 0; i < distance_ref_points_depth; i++) { > const __be32 *entry; > + int index = be32_to_cpu(distance_ref_points[i]) - index_offset; > > - entry = &associativity[be32_to_cpu(distance_ref_points[i])]; > + /* > + * broken hierarchy, return with broken distance table > + */ > + if (index > max_array_index) > + return; > + entry = &associativity[index]; > distance_lookup_table[nid][i] = of_read_number(entry, 1); > } > } > @@ -321,7 +360,7 @@ static void initialize_form1_numa_distance(struct device_node *node) > if (!associativity) > return; > > - __initialize_form1_numa_distance(associativity); > + __initialize_form1_numa_distance(associativity, false, 0); > } > > /* > @@ -586,27 +625,14 @@ static int get_nid_and_numa_distance(struct drmem_lmb *lmb) > > if (primary_domain_index <= aa.array_sz && > !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) { > - index = lmb->aa_index * aa.array_sz + primary_domain_index - 1; > - nid = of_read_number(&aa.arrays[index], 1); > + const __be32 *associativity; > > - if (nid == 0xffff || nid >= nr_node_ids) > - nid = default_nid; > + index = lmb->aa_index * aa.array_sz; > + associativity = &aa.arrays[index]; > + nid = __associativity_to_nid(associativity, true, aa.array_sz - 1); > if (nid > 0 && affinity_form == FORM1_AFFINITY) { > - int i; > - const __be32 *associativity; > - > - index = lmb->aa_index * aa.array_sz; > - associativity = &aa.arrays[index]; > - /* > - * lookup array associativity entries have different format > - * There is no length of the array as the first element. > - */ > - for (i = 0; i < distance_ref_points_depth; i++) { > - const __be32 *entry; > - > - entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1]; > - distance_lookup_table[nid][i] = of_read_number(entry, 1); > - } > + __initialize_form1_numa_distance(associativity, > + true, aa.array_sz - 1); > } > } > return nid; > @@ -632,9 +658,11 @@ int of_drconf_to_nid_single(struct drmem_lmb *lmb) > > if (primary_domain_index <= aa.array_sz && > !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) { > - index = lmb->aa_index * aa.array_sz + primary_domain_index - 1; > - nid = of_read_number(&aa.arrays[index], 1); > + const __be32 *associativity; > > + index = lmb->aa_index * aa.array_sz; > + associativity = &aa.arrays[index]; > + nid = __associativity_to_nid(associativity, true, aa.array_sz - 1); > if (nid == 0xffff || nid >= nr_node_ids) > nid = default_nid; > } > @@ -939,7 +967,7 @@ static int __init parse_numa_properties(void) > > if (__vphn_get_associativity(i, vphn_assoc) == 0) { > nid = associativity_to_nid(vphn_assoc); > - __initialize_form1_numa_distance(vphn_assoc); > + __initialize_form1_numa_distance(vphn_assoc, false, 0); > } else { > > /* > @@ -953,7 +981,7 @@ static int __init parse_numa_properties(void) > associativity = of_get_associativity(cpu); > if (associativity) { > nid = associativity_to_nid(associativity); > - __initialize_form1_numa_distance(associativity); > + __initialize_form1_numa_distance(associativity, false, 0); > } > of_node_put(cpu); > } > @@ -993,7 +1021,7 @@ static int __init parse_numa_properties(void) > associativity = of_get_associativity(memory); > if (associativity) { > nid = associativity_to_nid(associativity); > - __initialize_form1_numa_distance(associativity); > + __initialize_form1_numa_distance(associativity, false, 0); > } else > nid = default_nid; > > -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson