mm, truncate: do not check mapping for every page being truncated
During truncation, the mapping has already been checked for shmem and
dax so it's known that workingset_update_node is required.
This patch avoids the checks on mapping for each page being truncated.
In all other cases, a lookup helper is used to determine if
workingset_update_node() needs to be called. The one danger is that the
API is slightly harder to use as calling workingset_update_node directly
without checking for dax or shmem mappings could lead to surprises.
However, the API rarely needs to be used and hopefully the comment is
enough to give people the hint.
sparsetruncate (tiny)
4.14.0-rc4 4.14.0-rc4
oneirq-v1r1 pickhelper-v1r1
Min Time 141.00 ( 0.00%) 140.00 ( 0.71%)
1st-qrtle Time 142.00 ( 0.00%) 141.00 ( 0.70%)
2nd-qrtle Time 142.00 ( 0.00%) 142.00 ( 0.00%)
3rd-qrtle Time 143.00 ( 0.00%) 143.00 ( 0.00%)
Max-90% Time 144.00 ( 0.00%) 144.00 ( 0.00%)
Max-95% Time 147.00 ( 0.00%) 145.00 ( 1.36%)
Max-99% Time 195.00 ( 0.00%) 191.00 ( 2.05%)
Max Time 230.00 ( 0.00%) 205.00 ( 10.87%)
Amean Time 144.37 ( 0.00%) 143.82 ( 0.38%)
Stddev Time 10.44 ( 0.00%) 9.00 ( 13.74%)
Coeff Time 7.23 ( 0.00%) 6.26 ( 13.41%)
Best99%Amean Time 143.72 ( 0.00%) 143.34 ( 0.26%)
Best95%Amean Time 142.37 ( 0.00%) 142.00 ( 0.26%)
Best90%Amean Time 142.19 ( 0.00%) 141.85 ( 0.24%)
Best75%Amean Time 141.92 ( 0.00%) 141.58 ( 0.24%)
Best50%Amean Time 141.69 ( 0.00%) 141.31 ( 0.27%)
Best25%Amean Time 141.38 ( 0.00%) 140.97 ( 0.29%)
As you'd expect, the gain is marginal but it can be detected. The
differences in bonnie are all within the noise which is not surprising
given the impact on the microbenchmark.
radix_tree_update_node_t is a callback for some radix operations that
optionally passes in a private field. The only user of the callback is
workingset_update_node and as it no longer requires a mapping, the
private field is removed.
Link: http://lkml.kernel.org/r/20171018075952.10627-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/dax.c b/fs/dax.c
index 9ec7974..165fdfb 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -565,7 +565,7 @@
ret = __radix_tree_lookup(page_tree, index, &node, &slot);
WARN_ON_ONCE(ret != entry);
__radix_tree_replace(page_tree, node, slot,
- new_entry, NULL, NULL);
+ new_entry, NULL);
entry = new_entry;
}
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 567ebb5..0ca448c 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -301,18 +301,17 @@
void *radix_tree_lookup(const struct radix_tree_root *, unsigned long);
void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *,
unsigned long index);
-typedef void (*radix_tree_update_node_t)(struct radix_tree_node *, void *);
+typedef void (*radix_tree_update_node_t)(struct radix_tree_node *);
void __radix_tree_replace(struct radix_tree_root *, struct radix_tree_node *,
void __rcu **slot, void *entry,
- radix_tree_update_node_t update_node, void *private);
+ radix_tree_update_node_t update_node);
void radix_tree_iter_replace(struct radix_tree_root *,
const struct radix_tree_iter *, void __rcu **slot, void *entry);
void radix_tree_replace_slot(struct radix_tree_root *,
void __rcu **slot, void *entry);
void __radix_tree_delete_node(struct radix_tree_root *,
struct radix_tree_node *,
- radix_tree_update_node_t update_node,
- void *private);
+ radix_tree_update_node_t update_node);
void radix_tree_iter_delete(struct radix_tree_root *,
struct radix_tree_iter *iter, void __rcu **slot);
void *radix_tree_delete_item(struct radix_tree_root *, unsigned long, void *);
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 8b8a6f9..454f042 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -298,7 +298,18 @@
void *workingset_eviction(struct address_space *mapping, struct page *page);
bool workingset_refault(void *shadow);
void workingset_activation(struct page *page);
-void workingset_update_node(struct radix_tree_node *node, void *private);
+
+/* Do not use directly, use workingset_lookup_update */
+void workingset_update_node(struct radix_tree_node *node);
+
+/* Returns workingset_update_node() if the mapping has shadow entries. */
+#define workingset_lookup_update(mapping) \
+({ \
+ radix_tree_update_node_t __helper = workingset_update_node; \
+ if (dax_mapping(mapping) || shmem_mapping(mapping)) \
+ __helper = NULL; \
+ __helper; \
+})
/* linux/mm/page_alloc.c */
extern unsigned long totalram_pages;
diff --git a/lib/idr.c b/lib/idr.c
index edd9b2b..2593ce5 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -171,7 +171,7 @@
if (!slot || radix_tree_tag_get(&idr->idr_rt, id, IDR_FREE))
return ERR_PTR(-ENOENT);
- __radix_tree_replace(&idr->idr_rt, node, slot, ptr, NULL, NULL);
+ __radix_tree_replace(&idr->idr_rt, node, slot, ptr, NULL);
return entry;
}
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 8b1feca..c8d5556 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -677,8 +677,7 @@
* @root radix tree root
*/
static inline bool radix_tree_shrink(struct radix_tree_root *root,
- radix_tree_update_node_t update_node,
- void *private)
+ radix_tree_update_node_t update_node)
{
bool shrunk = false;
@@ -739,7 +738,7 @@
if (!radix_tree_is_internal_node(child)) {
node->slots[0] = (void __rcu *)RADIX_TREE_RETRY;
if (update_node)
- update_node(node, private);
+ update_node(node);
}
WARN_ON_ONCE(!list_empty(&node->private_list));
@@ -752,7 +751,7 @@
static bool delete_node(struct radix_tree_root *root,
struct radix_tree_node *node,
- radix_tree_update_node_t update_node, void *private)
+ radix_tree_update_node_t update_node)
{
bool deleted = false;
@@ -762,8 +761,8 @@
if (node->count) {
if (node_to_entry(node) ==
rcu_dereference_raw(root->rnode))
- deleted |= radix_tree_shrink(root, update_node,
- private);
+ deleted |= radix_tree_shrink(root,
+ update_node);
return deleted;
}
@@ -1173,7 +1172,6 @@
* @slot: pointer to slot in @node
* @item: new item to store in the slot.
* @update_node: callback for changing leaf nodes
- * @private: private data to pass to @update_node
*
* For use with __radix_tree_lookup(). Caller must hold tree write locked
* across slot lookup and replacement.
@@ -1181,7 +1179,7 @@
void __radix_tree_replace(struct radix_tree_root *root,
struct radix_tree_node *node,
void __rcu **slot, void *item,
- radix_tree_update_node_t update_node, void *private)
+ radix_tree_update_node_t update_node)
{
void *old = rcu_dereference_raw(*slot);
int exceptional = !!radix_tree_exceptional_entry(item) -
@@ -1201,9 +1199,9 @@
return;
if (update_node)
- update_node(node, private);
+ update_node(node);
- delete_node(root, node, update_node, private);
+ delete_node(root, node, update_node);
}
/**
@@ -1225,7 +1223,7 @@
void radix_tree_replace_slot(struct radix_tree_root *root,
void __rcu **slot, void *item)
{
- __radix_tree_replace(root, NULL, slot, item, NULL, NULL);
+ __radix_tree_replace(root, NULL, slot, item, NULL);
}
EXPORT_SYMBOL(radix_tree_replace_slot);
@@ -1242,7 +1240,7 @@
const struct radix_tree_iter *iter,
void __rcu **slot, void *item)
{
- __radix_tree_replace(root, iter->node, slot, item, NULL, NULL);
+ __radix_tree_replace(root, iter->node, slot, item, NULL);
}
#ifdef CONFIG_RADIX_TREE_MULTIORDER
@@ -1972,7 +1970,6 @@
* @root: radix tree root
* @node: node containing @index
* @update_node: callback for changing leaf nodes
- * @private: private data to pass to @update_node
*
* After clearing the slot at @index in @node from radix tree
* rooted at @root, call this function to attempt freeing the
@@ -1980,10 +1977,9 @@
*/
void __radix_tree_delete_node(struct radix_tree_root *root,
struct radix_tree_node *node,
- radix_tree_update_node_t update_node,
- void *private)
+ radix_tree_update_node_t update_node)
{
- delete_node(root, node, update_node, private);
+ delete_node(root, node, update_node);
}
static bool __radix_tree_delete(struct radix_tree_root *root,
@@ -2001,7 +1997,7 @@
node_tag_clear(root, node, tag, offset);
replace_slot(slot, NULL, node, -1, exceptional);
- return node && delete_node(root, node, NULL, NULL);
+ return node && delete_node(root, node, NULL);
}
/**
diff --git a/mm/filemap.c b/mm/filemap.c
index a470dd8..155370f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -35,6 +35,7 @@
#include <linux/hugetlb.h>
#include <linux/memcontrol.h>
#include <linux/cleancache.h>
+#include <linux/shmem_fs.h>
#include <linux/rmap.h>
#include "internal.h"
@@ -134,7 +135,7 @@
*shadowp = p;
}
__radix_tree_replace(&mapping->page_tree, node, slot, page,
- workingset_update_node, mapping);
+ workingset_lookup_update(mapping));
mapping->nrpages++;
return 0;
}
@@ -162,7 +163,7 @@
radix_tree_clear_tags(&mapping->page_tree, node, slot);
__radix_tree_replace(&mapping->page_tree, node, slot, shadow,
- workingset_update_node, mapping);
+ workingset_lookup_update(mapping));
}
page->mapping = NULL;
@@ -359,7 +360,7 @@
}
radix_tree_clear_tags(&mapping->page_tree, iter.node, slot);
__radix_tree_replace(&mapping->page_tree, iter.node, slot, NULL,
- workingset_update_node, mapping);
+ workingset_lookup_update(mapping));
total_pages++;
}
mapping->nrpages -= total_pages;
diff --git a/mm/shmem.c b/mm/shmem.c
index 07a1d22..a72f68a 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -338,7 +338,7 @@
if (item != expected)
return -ENOENT;
__radix_tree_replace(&mapping->page_tree, node, pslot,
- replacement, NULL, NULL);
+ replacement, NULL);
return 0;
}
diff --git a/mm/truncate.c b/mm/truncate.c
index 4a39a31..02a0c04 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -42,7 +42,7 @@
if (*slot != entry)
goto unlock;
__radix_tree_replace(&mapping->page_tree, node, slot, NULL,
- workingset_update_node, mapping);
+ workingset_update_node);
mapping->nrexceptional--;
unlock:
spin_unlock_irq(&mapping->tree_lock);
diff --git a/mm/workingset.c b/mm/workingset.c
index b997c9d..b7d616a 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -340,14 +340,8 @@
static struct list_lru shadow_nodes;
-void workingset_update_node(struct radix_tree_node *node, void *private)
+void workingset_update_node(struct radix_tree_node *node)
{
- struct address_space *mapping = private;
-
- /* Only regular page cache has shadow entries */
- if (dax_mapping(mapping) || shmem_mapping(mapping))
- return;
-
/*
* Track non-empty nodes that contain only shadow entries;
* unlink those that contain pages or are being freed.
@@ -475,7 +469,7 @@
goto out_invalid;
inc_lruvec_page_state(virt_to_page(node), WORKINGSET_NODERECLAIM);
__radix_tree_delete_node(&mapping->page_tree, node,
- workingset_update_node, mapping);
+ workingset_lookup_update(mapping));
out_invalid:
spin_unlock(&mapping->tree_lock);
diff --git a/tools/testing/radix-tree/multiorder.c b/tools/testing/radix-tree/multiorder.c
index 06c7117..59245b3 100644
--- a/tools/testing/radix-tree/multiorder.c
+++ b/tools/testing/radix-tree/multiorder.c
@@ -618,7 +618,7 @@
__radix_tree_insert(&tree, 1 << 5, 5, (void *)0x12);
__radix_tree_lookup(&tree, 1 << 5, &node, &slot);
assert(node->count == node->exceptional * 2);
- __radix_tree_replace(&tree, node, slot, NULL, NULL, NULL);
+ __radix_tree_replace(&tree, node, slot, NULL, NULL);
assert(node->exceptional == 0);
item_kill_tree(&tree);