See comments in code, and previous commit messages for details of
implementation and usage.
Fix whitespace while here.
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
---
.../admin-guide/mm/numa_memory_policy.rst | 16 ++++++++++++----
include/uapi/linux/mempolicy.h | 6 +++---
mm/mempolicy.c | 14 ++++++--------
mm/page_alloc.c | 3 ---
4 files changed, 21 insertions(+), 18 deletions(-)
diff --git a/Documentation/admin-guide/mm/numa_memory_policy.rst b/Documentation/admin-guide/mm/numa_memory_policy.rst
index 1ad020c459b8..b69963a37fc8 100644
--- a/Documentation/admin-guide/mm/numa_memory_policy.rst
+++ b/Documentation/admin-guide/mm/numa_memory_policy.rst
@@ -245,6 +245,14 @@ MPOL_INTERLEAVED
address range or file. During system boot up, the temporary
interleaved system default policy works in this mode.
+MPOL_PREFERRED_MANY
+ This mode specifies that the allocation should be attempted from the
+ nodemask specified in the policy. If that allocation fails, the kernel
+ will search other nodes, in order of increasing distance from the first
+ set bit in the nodemask based on information provided by the platform
+ firmware. It is similar to MPOL_PREFERRED with the main exception that
+ is is an error to have an empty nodemask.
+
NUMA memory policy supports the following optional mode flags:
MPOL_F_STATIC_NODES
@@ -253,10 +261,10 @@ MPOL_F_STATIC_NODES
nodes changes after the memory policy has been defined.
Without this flag, any time a mempolicy is rebound because of a
- change in the set of allowed nodes, the node (Preferred) or
- nodemask (Bind, Interleave) is remapped to the new set of
- allowed nodes. This may result in nodes being used that were
- previously undesired.
+ change in the set of allowed nodes, the preferred nodemask (Preferred
+ Many), preferred node (Preferred) or nodemask (Bind, Interleave) is
+ remapped to the new set of allowed nodes. This may result in nodes
+ being used that were previously undesired.
With this flag, if the user-specified nodes overlap with the
nodes allowed by the task's cpuset, then the memory policy is
diff --git a/include/uapi/linux/mempolicy.h b/include/uapi/linux/mempolicy.h
index 3354774af61e..ad3eee651d4e 100644
--- a/include/uapi/linux/mempolicy.h
+++ b/include/uapi/linux/mempolicy.h
@@ -16,13 +16,13 @@
*/
/* Policies */
-enum {
- MPOL_DEFAULT,
+enum { MPOL_DEFAULT,
MPOL_PREFERRED,
MPOL_BIND,
MPOL_INTERLEAVE,
MPOL_LOCAL,
- MPOL_MAX, /* always last member of enum */
+ MPOL_PREFERRED_MANY,
+ MPOL_MAX, /* always last member of enum */
};
/* Flags for set_mempolicy */
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index fb49bea41ab8..07e916f8f6b7 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -108,8 +108,6 @@
#include "internal.h"
-#define MPOL_PREFERRED_MANY MPOL_MAX
-
/* Internal flags */
#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
@@ -180,7 +178,7 @@ struct mempolicy *get_task_policy(struct task_struct *p)
static const struct mempolicy_operations {
int (*create)(struct mempolicy *pol, const nodemask_t *nodes);
void (*rebind)(struct mempolicy *pol, const nodemask_t *nodes);
-} mpol_ops[MPOL_MAX + 1];
+} mpol_ops[MPOL_MAX];
static inline int mpol_store_user_nodemask(const struct mempolicy *pol)
{
@@ -385,8 +383,8 @@ static void mpol_rebind_preferred_common(struct mempolicy *pol,
}
/* MPOL_PREFERRED_MANY allows multiple nodes to be set in 'nodes' */
-static void __maybe_unused mpol_rebind_preferred_many(struct mempolicy *pol,
- const nodemask_t *nodes)
+static void mpol_rebind_preferred_many(struct mempolicy *pol,
+ const nodemask_t *nodes)
{
mpol_rebind_preferred_common(pol, nodes, nodes);
}
@@ -448,7 +446,7 @@ void mpol_rebind_mm(struct mm_struct *mm, nodemask_t *new)
mmap_write_unlock(mm);
}
-static const struct mempolicy_operations mpol_ops[MPOL_MAX + 1] = {
+static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
[MPOL_DEFAULT] = {
.rebind = mpol_rebind_default,
},
@@ -466,8 +464,8 @@ static const struct mempolicy_operations mpol_ops[MPOL_MAX + 1] = {
},
/* MPOL_LOCAL is converted to MPOL_PREFERRED on policy creation */
[MPOL_PREFERRED_MANY] = {
- .create = NULL,
- .rebind = NULL,
+ .create = mpol_new_preferred_many,
+ .rebind = mpol_rebind_preferred_many,
},
};
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0f90419fe0d8..b89c9c2637bf 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4867,9 +4867,6 @@ struct zonelist *preferred_zonelist(gfp_t gfp_mask, const nodemask_t *prefmask,
nodemask_t pref;
int nid, local_node = numa_mem_id();
- /* Multi nodes not supported yet */
- VM_BUG_ON(prefmask && nodes_weight(*prefmask) != 1);
-
#define _isset(mask, node) \
(!(mask) || nodes_empty(*(mask)) ? 1 : node_isset(node, *(mask)))
/*
--
2.27.0
