Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit eb8c1e2c authored by Tejun Heo's avatar Tejun Heo
Browse files

x86-64, NUMA: Better explain numa_distance handling



Handling of out-of-bounds distances and allocation failure can use
better documentation.  Add it.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
parent ce003330
Loading
Loading
Loading
Loading
+10 −1
Original line number Diff line number Diff line
@@ -392,11 +392,12 @@ void __init numa_reset_distance(void)
{
	size_t size = numa_distance_cnt * numa_distance_cnt * sizeof(numa_distance[0]);

	/* numa_distance could be 1LU marking allocation failure, test cnt */
	if (numa_distance_cnt)
		memblock_x86_free_range(__pa(numa_distance),
					__pa(numa_distance) + size);
	numa_distance_cnt = 0;
	numa_distance = NULL;
	numa_distance = NULL;	/* enable table creation */
}

static int __init numa_alloc_distance(void)
@@ -447,6 +448,14 @@ static int __init numa_alloc_distance(void)
 * Set the distance from node @from to @to to @distance.  If distance table
 * doesn't exist, one which is large enough to accomodate all the currently
 * known nodes will be created.
 *
 * If such table cannot be allocated, a warning is printed and further
 * calls are ignored until the distance table is reset with
 * numa_reset_distance().
 *
 * If @from or @to is higher than the highest known node at the time of
 * table creation or @distance doesn't make sense, the call is ignored.
 * This is to allow simplification of specific NUMA config implementations.
 */
void __init numa_set_distance(int from, int to, int distance)
{
+5 −1
Original line number Diff line number Diff line
@@ -379,7 +379,11 @@ void __init numa_emulation(struct numa_meminfo *numa_meminfo, int numa_dist_cnt)
		if (emu_nid_to_phys[i] == NUMA_NO_NODE)
			emu_nid_to_phys[i] = 0;

	/* transform distance table */
	/*
	 * Transform distance table.  numa_set_distance() ignores all
	 * out-of-bound distances.  Just call it for every possible node
	 * combination.
	 */
	numa_reset_distance();
	for (i = 0; i < MAX_NUMNODES; i++) {
		for (j = 0; j < MAX_NUMNODES; j++) {