[PATCH 02/19] mm/mpol: Remove NUMA_INTERLEAVE_HIT

From: Peter Zijlstra
Date: Tue Jul 31 2012 - 15:44:50 EST


Since the NUMA_INTERLEAVE_HIT statistic is useless on its own; it wants
to be compared to either a total of interleave allocations or to a miss
count, remove it.

Fixing it would be possible, but since we've gone years without these
statistics I figure we can continue that way.

Also NUMA_HIT fully includes NUMA_INTERLEAVE_HIT so users might
switch to using that.

This cleans up some of the weird MPOL_INTERLEAVE allocation exceptions.

Cc: Lee Schermerhorn <Lee.Schermerhorn@xxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
drivers/base/node.c | 2 -
include/linux/mmzone.h | 1
mm/mempolicy.c | 68 +++++++++++++++----------------------------------
mm/vmstat.c | 1
4 files changed, 22 insertions(+), 50 deletions(-)
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -169,7 +169,7 @@ static ssize_t node_read_numastat(struct
node_page_state(dev->id, NUMA_HIT),
node_page_state(dev->id, NUMA_MISS),
node_page_state(dev->id, NUMA_FOREIGN),
- node_page_state(dev->id, NUMA_INTERLEAVE_HIT),
+ 0UL,
node_page_state(dev->id, NUMA_LOCAL),
node_page_state(dev->id, NUMA_OTHER));
}
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -137,7 +137,6 @@ enum zone_stat_item {
NUMA_HIT, /* allocated in intended node */
NUMA_MISS, /* allocated in non intended node */
NUMA_FOREIGN, /* was intended here, hit elsewhere */
- NUMA_INTERLEAVE_HIT, /* interleaver preferred this zone */
NUMA_LOCAL, /* allocation from local node */
NUMA_OTHER, /* allocation from other node */
#endif
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1553,11 +1553,29 @@ static nodemask_t *policy_nodemask(gfp_t
return NULL;
}

+/* Do dynamic interleaving for a process */
+static unsigned interleave_nodes(struct mempolicy *policy)
+{
+ unsigned nid, next;
+ struct task_struct *me = current;
+
+ nid = me->il_next;
+ next = next_node(nid, policy->v.nodes);
+ if (next >= MAX_NUMNODES)
+ next = first_node(policy->v.nodes);
+ if (next < MAX_NUMNODES)
+ me->il_next = next;
+ return nid;
+}
+
/* Return a zonelist indicated by gfp for node representing a mempolicy */
static struct zonelist *policy_zonelist(gfp_t gfp, struct mempolicy *policy,
int nd)
{
switch (policy->mode) {
+ case MPOL_INTERLEAVE:
+ nd = interleave_nodes(policy);
+ break;
case MPOL_PREFERRED:
if (!(policy->flags & MPOL_F_LOCAL))
nd = policy->v.preferred_node;
@@ -1579,21 +1597,6 @@ static struct zonelist *policy_zonelist(
return node_zonelist(nd, gfp);
}

-/* Do dynamic interleaving for a process */
-static unsigned interleave_nodes(struct mempolicy *policy)
-{
- unsigned nid, next;
- struct task_struct *me = current;
-
- nid = me->il_next;
- next = next_node(nid, policy->v.nodes);
- if (next >= MAX_NUMNODES)
- next = first_node(policy->v.nodes);
- if (next < MAX_NUMNODES)
- me->il_next = next;
- return nid;
-}
-
/*
* Depending on the memory policy provide a node from which to allocate the
* next slab entry.
@@ -1824,21 +1827,6 @@ bool mempolicy_nodemask_intersects(struc
return ret;
}

-/* Allocate a page in interleaved policy.
- Own path because it needs to do special accounting. */
-static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,
- unsigned nid)
-{
- struct zonelist *zl;
- struct page *page;
-
- zl = node_zonelist(nid, gfp);
- page = __alloc_pages(gfp, order, zl);
- if (page && page_zone(page) == zonelist_zone(&zl->_zonerefs[0]))
- inc_zone_page_state(page, NUMA_INTERLEAVE_HIT);
- return page;
-}
-
/**
* alloc_pages_vma - Allocate a page for a VMA.
*
@@ -1875,17 +1863,6 @@ alloc_pages_vma(gfp_t gfp, int order, st
pol = get_vma_policy(current, vma, addr);
cpuset_mems_cookie = get_mems_allowed();

- if (unlikely(pol->mode == MPOL_INTERLEAVE)) {
- unsigned nid;
-
- nid = interleave_nid(pol, vma, addr, PAGE_SHIFT + order);
- mpol_cond_put(pol);
- page = alloc_page_interleave(gfp, order, nid);
- if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
- goto retry_cpuset;
-
- return page;
- }
zl = policy_zonelist(gfp, pol, node);
if (unlikely(mpol_needs_cond_ref(pol))) {
/*
@@ -1943,12 +1920,9 @@ struct page *alloc_pages_current(gfp_t g
* No reference counting needed for current->mempolicy
* nor system default_policy
*/
- if (pol->mode == MPOL_INTERLEAVE)
- page = alloc_page_interleave(gfp, order, interleave_nodes(pol));
- else
- page = __alloc_pages_nodemask(gfp, order,
- policy_zonelist(gfp, pol, numa_node_id()),
- policy_nodemask(gfp, pol));
+ page = __alloc_pages_nodemask(gfp, order,
+ policy_zonelist(gfp, pol, numa_node_id()),
+ policy_nodemask(gfp, pol));

if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !page))
goto retry_cpuset;
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -717,7 +717,6 @@ const char * const vmstat_text[] = {
"numa_hit",
"numa_miss",
"numa_foreign",
- "numa_interleave",
"numa_local",
"numa_other",
#endif


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