The patch titled
Subject: mm/list_lru.c: replace nr_node_ids for loop with for_each_node()
has been added to the -mm tree. Its filename is
mm-replace-nr_node_ids-for-loop-with-for_each_node-in-list-lru.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-replace-nr_node_ids-for-loop-with-for_each_node-in-list-lru.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-replace-nr_node_ids-for-loop-with-for_each_node-in-list-lru.patch
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------------------------------------------------------
From: Raghavendra K T <raghavendra.kt@xxxxxxxxxxxxxxxxxx>
Subject: mm/list_lru.c: replace nr_node_ids for loop with for_each_node()
The functions used in the patch are in slowpath, which gets called
whenever alloc_super is called during mounts.
Though this should not make difference for the architectures with
sequential numa node ids, for the powerpc which can potentially have
sparse node ids (for e.g., 4 node system having numa ids, 0,1,16,17 is
common), this patch saves some unnecessary allocations for non existing
numa nodes.
Even without that saving, perhaps patch makes code more readable.
[vdavydov@xxxxxxxxxxxxx: take memcg_aware check outside for_each loop]
Signed-off-by: Raghavendra K T <raghavendra.kt@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Anton Blanchard <anton@xxxxxxxxx>
Cc: Nishanth Aravamudan <nacc@xxxxxxxxxxxxxxxxxx>
Cc: Greg Kurz <gkurz@xxxxxxxxxxxxxxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxx>
Cc: Nikunj A Dadhania <nikunj@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/list_lru.c | 34 +++++++++++++++++++++++-----------
1 file changed, 23 insertions(+), 11 deletions(-)
diff -puN mm/list_lru.c~mm-replace-nr_node_ids-for-loop-with-for_each_node-in-list-lru mm/list_lru.c
--- a/mm/list_lru.c~mm-replace-nr_node_ids-for-loop-with-for_each_node-in-list-lru
+++ a/mm/list_lru.c
@@ -42,6 +42,10 @@ static void list_lru_unregister(struct l
#ifdef CONFIG_MEMCG_KMEM
static inline bool list_lru_memcg_aware(struct list_lru *lru)
{
+ /*
+ * This needs node 0 to be always present, even
+ * in the systems supporting sparse numa ids.
+ */
return !!lru->node[0].memcg_lrus;
}
@@ -377,16 +381,20 @@ static int memcg_init_list_lru(struct li
{
int i;
- for (i = 0; i < nr_node_ids; i++) {
- if (!memcg_aware)
- lru->node[i].memcg_lrus = NULL;
- else if (memcg_init_list_lru_node(&lru->node[i]))
+ if (!memcg_aware)
+ return 0;
+
+ for_each_node(i) {
+ if (memcg_init_list_lru_node(&lru->node[i]))
goto fail;
}
return 0;
fail:
- for (i = i - 1; i >= 0; i--)
+ for (i = i - 1; i >= 0; i--) {
+ if (!lru->node[i].memcg_lrus)
+ continue;
memcg_destroy_list_lru_node(&lru->node[i]);
+ }
return -ENOMEM;
}
@@ -397,7 +405,7 @@ static void memcg_destroy_list_lru(struc
if (!list_lru_memcg_aware(lru))
return;
- for (i = 0; i < nr_node_ids; i++)
+ for_each_node(i)
memcg_destroy_list_lru_node(&lru->node[i]);
}
@@ -409,16 +417,20 @@ static int memcg_update_list_lru(struct
if (!list_lru_memcg_aware(lru))
return 0;
- for (i = 0; i < nr_node_ids; i++) {
+ for_each_node(i) {
if (memcg_update_list_lru_node(&lru->node[i],
old_size, new_size))
goto fail;
}
return 0;
fail:
- for (i = i - 1; i >= 0; i--)
+ for (i = i - 1; i >= 0; i--) {
+ if (!lru->node[i].memcg_lrus)
+ continue;
+
memcg_cancel_update_list_lru_node(&lru->node[i],
old_size, new_size);
+ }
return -ENOMEM;
}
@@ -430,7 +442,7 @@ static void memcg_cancel_update_list_lru
if (!list_lru_memcg_aware(lru))
return;
- for (i = 0; i < nr_node_ids; i++)
+ for_each_node(i)
memcg_cancel_update_list_lru_node(&lru->node[i],
old_size, new_size);
}
@@ -485,7 +497,7 @@ static void memcg_drain_list_lru(struct
if (!list_lru_memcg_aware(lru))
return;
- for (i = 0; i < nr_node_ids; i++)
+ for_each_node(i)
memcg_drain_list_lru_node(&lru->node[i], src_idx, dst_idx);
}
@@ -522,7 +534,7 @@ int __list_lru_init(struct list_lru *lru
if (!lru->node)
goto out;
- for (i = 0; i < nr_node_ids; i++) {
+ for_each_node(i) {
spin_lock_init(&lru->node[i].lock);
if (key)
lockdep_set_class(&lru->node[i].lock, key);
_
Patches currently in -mm which might be from raghavendra.kt@xxxxxxxxxxxxxxxxxx are
mm-replace-nr_node_ids-for-loop-with-for_each_node-in-list-lru.patch
powerpc-numa-do-not-allocate-bootmem-memory-for-non-existing-nodes.patch
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