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Re: [PATCH] spapr_numa.c: fixes in spapr_numa_FORM2_write_rtas_tables()
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [PATCH] spapr_numa.c: fixes in spapr_numa_FORM2_write_rtas_tables() |
Date: |
Wed, 22 Sep 2021 13:17:32 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.1.0 |
On 9/21/21 21:43, Daniel Henrique Barboza wrote:
This patch has a handful of modifications for the recent added
FORM2 support:
- there is no particular reason for both 'lookup_index_table' and
'distance_table' to be allocated in the heap, since their sizes are
known right at the start of the function. Use static allocation in
them to spare a couple of g_new0() calls;
- to not allocate more than the necessary size in 'distance_table'. At
this moment the array is oversized due to allocating uint32_t for all
elements, when most of them fits in an uint8_t;
- create a NUMA_LOCAL_DISTANCE macro to avoid hardcoding the local
distance value.
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
hw/ppc/spapr_numa.c | 35 +++++++++++++++++++----------------
1 file changed, 19 insertions(+), 16 deletions(-)
diff --git a/hw/ppc/spapr_numa.c b/hw/ppc/spapr_numa.c
index 58d5dc7084..039a0439c6 100644
--- a/hw/ppc/spapr_numa.c
+++ b/hw/ppc/spapr_numa.c
@@ -19,6 +19,9 @@
/* Moved from hw/ppc/spapr_pci_nvlink2.c */
#define SPAPR_GPU_NUMA_ID (cpu_to_be32(1))
+/* Macro to avoid hardcoding the local distance value */
+#define NUMA_LOCAL_DISTANCE 10
+
/*
* Retrieves max_dist_ref_points of the current NUMA affinity.
*/
@@ -500,17 +503,21 @@ static void
spapr_numa_FORM2_write_rtas_tables(SpaprMachineState *spapr,
MachineState *ms = MACHINE(spapr);
NodeInfo *numa_info = ms->numa_state->nodes;
int nb_numa_nodes = ms->numa_state->num_nodes;
+ /* Lookup index table has an extra uint32_t with its length */
+ uint32_t lookup_index_table[nb_numa_nodes + 1];
int distance_table_entries = nb_numa_nodes * nb_numa_nodes;
- g_autofree uint32_t *lookup_index_table = NULL;
- g_autofree uint32_t *distance_table = NULL;
- int src, dst, i, distance_table_size;
- uint8_t *node_distances;
This should have be of ptrdiff_t type.
+ /*
+ * Distance table is an uint8_t array with a leading uint32_t
+ * containing its length.
+ */
+ uint8_t distance_table[distance_table_entries + 4];
The previous code seems better by using the heap, now we have
to worry about stack overflow...
+ uint32_t *distance_table_length;
Please drop, ...
+ int src, dst, i;
/*
* ibm,numa-lookup-index-table: array with length and a
* list of NUMA ids present in the guest.
*/
- lookup_index_table = g_new0(uint32_t, nb_numa_nodes + 1);
lookup_index_table[0] = cpu_to_be32(nb_numa_nodes);
for (i = 0; i < nb_numa_nodes; i++) {
@@ -518,8 +525,7 @@ static void
spapr_numa_FORM2_write_rtas_tables(SpaprMachineState *spapr,
}
_FDT(fdt_setprop(fdt, rtas, "ibm,numa-lookup-index-table",
- lookup_index_table,
- (nb_numa_nodes + 1) * sizeof(uint32_t)));
+ lookup_index_table, sizeof(lookup_index_table)));
/*
* ibm,numa-distance-table: contains all node distances. First
@@ -531,11 +537,10 @@ static void
spapr_numa_FORM2_write_rtas_tables(SpaprMachineState *spapr,
* array because NUMA ids can be sparse (node 0 is the first,
* node 8 is the second ...).
*/
- distance_table = g_new0(uint32_t, distance_table_entries + 1);
- distance_table[0] = cpu_to_be32(distance_table_entries);
+ distance_table_length = (uint32_t *)distance_table;
+ distance_table_length[0] = cpu_to_be32(distance_table_entries);
... and use instead:
stl_be_p(distance_table, distance_table_entries);
- node_distances = (uint8_t *)&distance_table[1];
- i = 0;
+ i = 4;
for (src = 0; src < nb_numa_nodes; src++) {
for (dst = 0; dst < nb_numa_nodes; dst++) {
@@ -546,18 +551,16 @@ static void
spapr_numa_FORM2_write_rtas_tables(SpaprMachineState *spapr,
* adding the numa_info to retrieve distance info from.
*/
if (src == dst) {
- node_distances[i++] = 10;
+ distance_table[i++] = NUMA_LOCAL_DISTANCE;
continue;
}
- node_distances[i++] = numa_info[src].distance[dst];
+ distance_table[i++] = numa_info[src].distance[dst];
}
}
- distance_table_size = distance_table_entries * sizeof(uint8_t) +
- sizeof(uint32_t);
_FDT(fdt_setprop(fdt, rtas, "ibm,numa-distance-table",
- distance_table, distance_table_size));
+ distance_table, sizeof(distance_table)));
}
/*