The patch titled
Subject: radix-tree: replace preallocated node array with linked list
has been added to the -mm tree. Its filename is
radix-tree-replace-preallocated-node-array-with-linked-list.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/radix-tree-replace-preallocated-node-array-with-linked-list.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/radix-tree-replace-preallocated-node-array-with-linked-list.patch
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: radix-tree: replace preallocated node array with linked list
Currently we use per-cpu array to hold pointers to preallocated nodes.
Let's replace it with linked list. On x86_64 it saves 256 bytes in
per-cpu ELF section which may translate into freeing up 2MB of memory for
NR_CPUS==8192.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/radix-tree.c | 27 ++++++++++++++++-----------
1 file changed, 16 insertions(+), 11 deletions(-)
diff -puN lib/radix-tree.c~radix-tree-replace-preallocated-node-array-with-linked-list lib/radix-tree.c
--- a/lib/radix-tree.c~radix-tree-replace-preallocated-node-array-with-linked-list
+++ a/lib/radix-tree.c
@@ -65,7 +65,8 @@ static struct kmem_cache *radix_tree_nod
*/
struct radix_tree_preload {
int nr;
- struct radix_tree_node *nodes[RADIX_TREE_PRELOAD_SIZE];
+ /* nodes->private_data points to next prealocated node */
+ struct radix_tree_node *nodes;
};
static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
@@ -197,8 +198,9 @@ radix_tree_node_alloc(struct radix_tree_
*/
rtp = this_cpu_ptr(&radix_tree_preloads);
if (rtp->nr) {
- ret = rtp->nodes[rtp->nr - 1];
- rtp->nodes[rtp->nr - 1] = NULL;
+ ret = rtp->nodes;
+ rtp->nodes = ret->private_data;
+ ret->private_data = NULL;
rtp->nr--;
}
/*
@@ -257,16 +259,18 @@ static int __radix_tree_preload(gfp_t gf
preempt_disable();
rtp = this_cpu_ptr(&radix_tree_preloads);
- while (rtp->nr < ARRAY_SIZE(rtp->nodes)) {
+ while (rtp->nr < RADIX_TREE_PRELOAD_SIZE) {
preempt_enable();
node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
if (node == NULL)
goto out;
preempt_disable();
rtp = this_cpu_ptr(&radix_tree_preloads);
- if (rtp->nr < ARRAY_SIZE(rtp->nodes))
- rtp->nodes[rtp->nr++] = node;
- else
+ if (rtp->nr < RADIX_TREE_PRELOAD_SIZE) {
+ node->private_data = rtp->nodes;
+ rtp->nodes = node;
+ rtp->nr++;
+ } else
kmem_cache_free(radix_tree_node_cachep, node);
}
ret = 0;
@@ -1463,15 +1467,16 @@ static int radix_tree_callback(struct no
{
int cpu = (long)hcpu;
struct radix_tree_preload *rtp;
+ struct radix_tree_node *node;
/* Free per-cpu pool of perloaded nodes */
if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
rtp = &per_cpu(radix_tree_preloads, cpu);
while (rtp->nr) {
- kmem_cache_free(radix_tree_node_cachep,
- rtp->nodes[rtp->nr-1]);
- rtp->nodes[rtp->nr-1] = NULL;
- rtp->nr--;
+ node = rtp->nodes;
+ rtp->nodes = node->private_data;
+ kmem_cache_free(radix_tree_node_cachep, node);
+ rtp->nr--;
}
}
return NOTIFY_OK;
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
mm-fix-mprotect-behaviour-on-vm_locked-vmas.patch
mm-fix-mprotect-behaviour-on-vm_locked-vmas-fix.patch
mm-new-mm-hook-framework.patch
mm-new-arch_remap-hook.patch
powerpc-mm-tracking-vdso-remap.patch
mm-drop-bogus-vm_bug_on_page-assert-in-put_page-codepath.patch
mm-avoid-tail-page-refcounting-on-non-thp-compound-pages.patch
rmap-fix-theoretical-race-between-do_wp_page-and-shrink_active_list.patch
rmap-fix-theoretical-race-between-do_wp_page-and-shrink_active_list-fix.patch
rmap-fix-theoretical-race-between-do_wp_page-and-shrink_active_list-fix-fix.patch
mm-thp-split-out-pmd-collpase-flush-into-a-separate-functions.patch
mm-thp-split-out-pmd-collpase-flush-into-a-separate-functions-fix.patch
powerpc-mm-use-generic-version-of-pmdp_clear_flush.patch
mm-clarify-that-the-function-operateds-on-hugepage-pte.patch
page-flags-trivial-cleanup-for-pagetrans-helpers.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages.patch
page-flags-define-pg_locked-behavior-on-compound-pages.patch
page-flags-define-behavior-of-fs-io-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-lru-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-lru-related-flags-on-compound-pages-fix.patch
page-flags-define-behavior-slb-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-xen-related-flags-on-compound-pages.patch
page-flags-define-pg_reserved-behavior-on-compound-pages.patch
page-flags-define-pg_swapbacked-behavior-on-compound-pages.patch
page-flags-define-pg_swapcache-behavior-on-compound-pages.patch
page-flags-define-pg_mlocked-behavior-on-compound-pages.patch
page-flags-define-pg_uncached-behavior-on-compound-pages.patch
page-flags-define-pg_uptodate-behavior-on-compound-pages.patch
page-flags-look-on-head-page-if-the-flag-is-encoded-in-page-mapping.patch
mm-sanitize-page-mapping-for-tail-pages.patch
include-linux-page-flagsh-rename-macros-to-avoid-collisions.patch
radix-tree-replace-preallocated-node-array-with-linked-list.patch
radix-tree-replace-preallocated-node-array-with-linked-list-fix.patch
linux-next.patch
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