From: Gregory Price <gregory@xxxxxxxxxxxxxxxx>
Extend set_mempolicy2 and mbind2 to support weighted interleave, and
demonstrate the extensibility of the mpol_args structure.
To support weighted interleave we add interleave weight fields to the
following structures:
Kernel Internal: (include/linux/mempolicy.h)
struct mempolicy {
/* task-local weights to apply to weighted interleave */
unsigned char weights[MAX_NUMNODES];
}
struct mempolicy_args {
/* Optional: interleave weights for MPOL_WEIGHTED_INTERLEAVE */
unsigned char *il_weights; /* of size MAX_NUMNODES */
}
UAPI: (/include/uapi/linux/mempolicy.h)
struct mpol_args {
/* Optional: interleave weights for MPOL_WEIGHTED_INTERLEAVE */
unsigned char *il_weights; /* of size pol_max_nodes */
}
The task-local weights are a single, one-dimensional array of weights
that apply to all possible nodes on the system. If a node is set in
the mempolicy nodemask, the weight in `il_weights` must be >= 1,
otherwise set_mempolicy2() will return -EINVAL. If a node is not
set in pol_nodemask, the weight will default to `1` in the task policy.
The default value of `1` is required to handle the situation where a
task migrates to a set of nodes for which weights were not set (up to
and including the local numa node). For example, a migrated task whose
nodemask changes entirely will have all its weights defaulted back
to `1`, or if the nodemask changes to include a mix of nodes that
were not previously accounted for - the weighted interleave may be
suboptimal.
If migrations are expected, a task should prefer not to use task-local
interleave weights, and instead utilize the global settings for natural
re-weighting on migration.
To support global vs local weighting, we add the kernel-internal flag:
MPOL_F_GWEIGHT (1 << 5) /* Utilize global weights */
This flag is set when il_weights is omitted by set_mempolicy2(), or
when MPOL_WEIGHTED_INTERLEAVE is set by set_mempolicy(). This internal
mode_flag dictates whether global weights or task-local weights are
utilized by the the various weighted interleave functions:
* weighted_interleave_nodes
* weighted_interleave_nid
* alloc_pages_bulk_array_weighted_interleave
if (pol->flags & MPOL_F_GWEIGHT)
pol_weights = iw_table[numa_node_id()].weights;
else
pol_weights = pol->wil.weights;
To simplify creations and duplication of mempolicies, the weights are
added as a structure directly within mempolicy. This allows the
existing logic in __mpol_dup to copy the weights without additional
allocations:
if (old == current->mempolicy) {
task_lock(current);
*new = *old;
task_unlock(current);
} else
*new = *old
Suggested-by: Rakie Kim <rakie.kim@xxxxxx>
Suggested-by: Hyeongtak Ji <hyeongtak.ji@xxxxxx>
Suggested-by: Honggyu Kim <honggyu.kim@xxxxxx>
Suggested-by: Vinicius Tavares Petrucci <vtavarespetr@xxxxxxxxxx>
Signed-off-by: Gregory Price <gregory.price@xxxxxxxxxxxx>
Co-developed-by: Rakie Kim <rakie.kim@xxxxxx>
Signed-off-by: Rakie Kim <rakie.kim@xxxxxx>
Co-developed-by: Hyeongtak Ji <hyeongtak.ji@xxxxxx>
Signed-off-by: Hyeongtak Ji <hyeongtak.ji@xxxxxx>
Co-developed-by: Honggyu Kim <honggyu.kim@xxxxxx>
Signed-off-by: Honggyu Kim <honggyu.kim@xxxxxx>
Co-developed-by: Vinicius Tavares Petrucci <vtavarespetr@xxxxxxxxxx>
Signed-off-by: Vinicius Tavares Petrucci <vtavarespetr@xxxxxxxxxx>
---
.../admin-guide/mm/numa_memory_policy.rst | 13 ++-
include/linux/mempolicy.h | 2 +
include/uapi/linux/mempolicy.h | 3 +
mm/mempolicy.c | 87 ++++++++++++++++++-
4 files changed, 100 insertions(+), 5 deletions(-)
diff --git a/Documentation/admin-guide/mm/numa_memory_policy.rst b/Documentation/admin-guide/mm/numa_memory_policy.rst
index 72ab21e24ec2..f3a9dcbaa7ed 100644
--- a/Documentation/admin-guide/mm/numa_memory_policy.rst
+++ b/Documentation/admin-guide/mm/numa_memory_policy.rst
@@ -254,7 +254,8 @@ MPOL_WEIGHTED_INTERLEAVE
This mode operates the same as MPOL_INTERLEAVE, except that
interleaving behavior is executed based on weights set in
/sys/kernel/mm/mempolicy/weighted_interleave/
- rather than simple round-robin interleave (which is the default).
+ when configured to utilize global weights, or based on task-local
+ weights configured with set_mempolicy2(2) or mbind2(2).
When utilizing global weights from the sysfs interface,
weights are applied in a src-node relative manner. For example
@@ -267,6 +268,13 @@ MPOL_WEIGHTED_INTERLEAVE
cgroup initiated migrations) to re-weight for the optimal
distribution of bandwidth.
+ When utilizing task-local weights, weights are not rebalanced
+ in the event of a task migration. If a weight has not been
+ explicitly set for a node set in the new nodemask, the
+ value of that weight defaults to "1". For this reason, if
+ migrations are expected or possible, users should consider
+ utilizing global interleave weights.
+
NUMA memory policy supports the following optional mode flags:
MPOL_F_STATIC_NODES
@@ -533,6 +541,9 @@ Extended Mempolicy Arguments::
/* mbind2: address ranges to apply the policy */
struct iovec *vec;
size_t vlen;
+
+ /* weighted interleave settings */
+ unsigned char *il_weights; /* of size pol_maxnodes */
};
The extended mempolicy argument structure is defined to allow the mempolicy
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 117c5395c6eb..c78874bd84dd 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -58,6 +58,7 @@ struct mempolicy {
/* Weighted interleave settings */
struct {
unsigned char cur_weight;
+ unsigned char weights[MAX_NUMNODES];
} wil;
};
@@ -73,6 +74,7 @@ struct mempolicy_args {
unsigned long addr; /* get: vma address */
int addr_node; /* get: node the address belongs to */
int home_node; /* mbind: use MPOL_MF_HOME_NODE */
+ unsigned char *il_weights; /* for mode MPOL_WEIGHTED_INTERLEAVE */
};
/*
diff --git a/include/uapi/linux/mempolicy.h b/include/uapi/linux/mempolicy.h
index 3e463442fe28..c2f229037be3 100644
--- a/include/uapi/linux/mempolicy.h
+++ b/include/uapi/linux/mempolicy.h
@@ -43,6 +43,8 @@ struct mpol_args {
/* mbind2: address ranges to apply the policy */
struct iovec *vec;
size_t vlen;
+ /* weighted interleave settings */
+ unsigned char *il_weights; /* of size pol_maxnodes */
};
/* Flags for set_mempolicy */
@@ -83,6 +85,7 @@ struct mpol_args {
#define MPOL_F_SHARED (1 << 0) /* identify shared policies */
#define MPOL_F_MOF (1 << 3) /* this policy wants migrate on fault */
#define MPOL_F_MORON (1 << 4) /* Migrate On protnone Reference On Node */
+#define MPOL_F_GWEIGHT (1 << 5) /* Utilize global weights */
/*
* These bit locations are exposed in the vm.zone_reclaim_mode sysctl
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index c203cea52ce9..7273bb9540fa 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -274,6 +274,7 @@ static struct mempolicy *mpol_new(struct mempolicy_args *args)
unsigned short mode = args->mode;
unsigned short flags = args->mode_flags;
nodemask_t *nodes = args->policy_nodes;
+ int node;
if (mode == MPOL_DEFAULT) {
if (nodes && !nodes_empty(*nodes))
@@ -300,6 +301,19 @@ static struct mempolicy *mpol_new(struct mempolicy_args *args)
(flags & MPOL_F_STATIC_NODES) ||
(flags & MPOL_F_RELATIVE_NODES))
return ERR_PTR(-EINVAL);
+ } else if (mode == MPOL_WEIGHTED_INTERLEAVE) {
+ /* weighted interleave requires a nodemask and weights > 0 */
+ if (nodes_empty(*nodes))
+ return ERR_PTR(-EINVAL);
+ if (args->il_weights) {
+ node = first_node(*nodes);
+ while (node != MAX_NUMNODES) {
+ if (!args->il_weights[node])
+ return ERR_PTR(-EINVAL);
+ node = next_node(node, *nodes);
+ }
+ } else if (!(args->mode_flags & MPOL_F_GWEIGHT))
+ return ERR_PTR(-EINVAL);
} else if (nodes_empty(*nodes))
return ERR_PTR(-EINVAL);
@@ -312,6 +326,16 @@ static struct mempolicy *mpol_new(struct mempolicy_args *args)
policy->home_node = NUMA_NO_NODE;
policy->wil.cur_weight = 0;
policy->home_node = args->home_node;
+ if (policy->mode == MPOL_WEIGHTED_INTERLEAVE && args->il_weights) {
+ policy->wil.cur_weight = 0;
+ /* Minimum weight value is always 1 */
+ memset(policy->wil.weights, 1, MAX_NUMNODES);
+ node = first_node(*nodes);
+ while (node != MAX_NUMNODES) {
+ policy->wil.weights[node] = args->il_weights[node];
+ node = next_node(node, *nodes);
+ }
+ }
return policy;
}
@@ -1612,6 +1636,7 @@ SYSCALL_DEFINE3(mbind2, struct mpol_args __user *, uargs, size_t, usize,
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
struct iov_iter iter;
+ unsigned char weights[MAX_NUMNODES];
int err;
err = copy_struct_from_user(&kargs, sizeof(kargs), uargs, usize);
@@ -1648,6 +1673,19 @@ SYSCALL_DEFINE3(mbind2, struct mpol_args __user *, uargs, size_t, usize,
} else
margs.policy_nodes = NULL;
+ if (kargs.mode == MPOL_WEIGHTED_INTERLEAVE) {
+ err = copy_struct_from_user(&weights,
+ sizeof(weights),
+ &kargs.il_weights,
+ kargs.pol_maxnodes);
+ if (err)
+ return err;
+ margs.il_weights = weights;
+ } else {
+ margs.il_weights = NULL;
+ flags |= MPOL_F_GWEIGHT;
+ }
+
/* For each address range in vector, do_mbind */
err = import_iovec(ITER_DEST, kargs.vec, kargs.vlen,
ARRAY_SIZE(iovstack), &iov, &iter);
@@ -1686,6 +1724,9 @@ static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,
if (err)
return err;
+ if (mode & MPOL_WEIGHTED_INTERLEAVE)
+ mode_flags |= MPOL_F_GWEIGHT;
+
memset(&args, 0, sizeof(args));
args.mode = lmode;
args.mode_flags = mode_flags;
@@ -1708,6 +1749,7 @@ SYSCALL_DEFINE3(set_mempolicy2, struct mpol_args __user *, uargs, size_t, usize,
struct mempolicy_args margs;
int err;
nodemask_t policy_nodemask;
+ unsigned char weights[MAX_NUMNODES];
if (flags)
return -EINVAL;
@@ -1732,6 +1774,19 @@ SYSCALL_DEFINE3(set_mempolicy2, struct mpol_args __user *, uargs, size_t, usize,
} else
margs.policy_nodes = NULL;
+ if (kargs.mode == MPOL_WEIGHTED_INTERLEAVE && kargs.il_weights) {
+ err = copy_struct_from_user(weights,
+ sizeof(weights),
+ kargs.il_weights,
+ kargs.pol_maxnodes);
+ if (err)
+ return err;
+ margs.il_weights = weights;
+ } else {
+ margs.il_weights = NULL;
+ flags |= MPOL_F_GWEIGHT;
+ }
+
return do_set_mempolicy(&margs);
}
@@ -2081,16 +2136,22 @@ static unsigned int weighted_interleave_nodes(struct mempolicy *policy)
{
unsigned int next;
struct task_struct *me = current;
+ unsigned char *weights;
if (policy->wil.cur_weight > 0) {
policy->wil.cur_weight--;
return me->il_prev;
}
+ if (policy->flags & MPOL_F_GWEIGHT)
+ weights = iw_table[numa_node_id()].weights;
+ else
+ weights = policy->wil.weights;
+
next = next_node_in(me->il_prev, policy->nodes);
if (next < MAX_NUMNODES) {
me->il_prev = next;
- policy->wil.cur_weight = iw_table[numa_node_id()].weights[next];
+ policy->wil.cur_weight = weights[next];
}
return next;
}
@@ -2160,15 +2221,21 @@ static unsigned int weighted_interleave_nid(struct mempolicy *pol, pgoff_t ilx)
{
nodemask_t nodemask = pol->nodes;
unsigned int target, weight_total = 0;
- int nid, local_node = numa_node_id();
+ int nid;
+ unsigned char *pol_weights;
unsigned char weights[MAX_NUMNODES];
unsigned char weight;
barrier();
+ if (pol->flags & MPOL_F_GWEIGHT)
+ pol_weights = iw_table[numa_node_id()].weights;
+ else
+ pol_weights = pol->wil.weights;
+
/* Collect weights and save them on stack so they don't change */
for_each_node_mask(nid, nodemask) {
- weight = iw_table[local_node].weights[nid];
+ weight = pol_weights[nid];
weight_total += weight;
weights[nid] = weight;
}
@@ -2564,6 +2631,7 @@ static unsigned long alloc_pages_bulk_array_weighted_interleave(gfp_t gfp,
unsigned long nr_allocated;
unsigned long rounds;
unsigned long node_pages, delta;
+ unsigned char *pol_weights;
unsigned char weight;
unsigned char weights[MAX_NUMNODES];
unsigned int weight_total;
@@ -2576,9 +2644,14 @@ static unsigned long alloc_pages_bulk_array_weighted_interleave(gfp_t gfp,
nnodes = nodes_weight(nodes);
+ if (pol->flags & MPOL_F_GWEIGHT)
+ pol_weights = iw_table[numa_node_id()].weights;
+ else
+ pol_weights = pol->wil.weights;
+
/* Collect weights and save them on stack so they don't change */
for_each_node_mask(node, nodes) {
- weight = iw_table[numa_node_id()].weights[node];
+ weight = pol_weights[node];
weight_total += weight;
weights[node] = weight;
}
@@ -3095,6 +3168,7 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
{
int ret;
struct mempolicy_args margs;
+ unsigned char weights[MAX_NUMNODES];
sp->root = RB_ROOT; /* empty tree == default mempolicy */
rwlock_init(&sp->lock);
@@ -3112,6 +3186,11 @@ void mpol_shared_policy_init(struct shared_policy *sp, struct mempolicy *mpol)
margs.mode_flags = mpol->flags;
margs.policy_nodes = &mpol->w.user_nodemask;
margs.home_node = NUMA_NO_NODE;
+ if (margs.mode == MPOL_WEIGHTED_INTERLEAVE &&
+ !(margs.mode_flags & MPOL_F_GWEIGHT)) {
+ memcpy(weights, mpol->wil.weights, sizeof(weights));
+ margs.il_weights = weights;
+ }
/* contextualize the tmpfs mount point mempolicy to this file */
npol = mpol_new(&margs);
--
2.39.1
