The patch titled
page_cgroup: reduce allocation overhead for page_cgroup array for CONFIG_SPARSEMEM
has been removed from the -mm tree. Its filename was
page_cgroup-reduce-allocation-overhead-for-page_cgroup-array-for-config_sparsemem.patch
This patch was dropped because it was merged into mainline or a subsystem tree
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: page_cgroup: reduce allocation overhead for page_cgroup array for CONFIG_SPARSEMEM
From: Michal Hocko <mhocko@xxxxxxx>
Currently we are allocating a single page_cgroup array per memory section
(stored in mem_section->base) when CONFIG_SPARSEMEM is selected. This is
correct but memory inefficient solution because the allocated memory
(unless we fall back to vmalloc) is not kmalloc friendly:
- 32b - 16384 entries (20B per entry) fit into 327680B so the
524288B slab cache is used
- 32b with PAE - 131072 entries with 2621440B fit into 4194304B
- 64b - 32768 entries (40B per entry) fit into 2097152 cache
This is ~37% wasted space per memory section and it sumps up for the whole
memory. On a x86_64 machine it is something like 6MB per 1GB of RAM.
We can reduce the internal fragmentation by using alloc_pages_exact which
allocates PAGE_SIZE aligned blocks so we will get down to <4kB wasted
memory per section which is much better.
We still need a fallback to vmalloc because we have no guarantees that we
will have a continuous memory of that size (order-10) later on during the
hotplug events.
[hannes@xxxxxxxxxxx: do not define unused free_page_cgroup() without memory hotplug]
Signed-off-by: Michal Hocko <mhocko@xxxxxxx>
Cc: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_cgroup.c | 58 +++++++++++++++++++++++++++------------------
1 file changed, 36 insertions(+), 22 deletions(-)
diff -puN mm/page_cgroup.c~page_cgroup-reduce-allocation-overhead-for-page_cgroup-array-for-config_sparsemem mm/page_cgroup.c
--- a/mm/page_cgroup.c~page_cgroup-reduce-allocation-overhead-for-page_cgroup-array-for-config_sparsemem
+++ a/mm/page_cgroup.c
@@ -130,7 +130,38 @@ struct page *lookup_cgroup_page(struct p
return page;
}
-/* __alloc_bootmem...() is protected by !slab_available() */
+static void *__init_refok alloc_page_cgroup(size_t size, int nid)
+{
+ void *addr = NULL;
+
+ addr = alloc_pages_exact(size, GFP_KERNEL | __GFP_NOWARN);
+ if (addr)
+ return addr;
+
+ if (node_state(nid, N_HIGH_MEMORY))
+ addr = vmalloc_node(size, nid);
+ else
+ addr = vmalloc(size);
+
+ return addr;
+}
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+static void free_page_cgroup(void *addr)
+{
+ if (is_vmalloc_addr(addr)) {
+ vfree(addr);
+ } else {
+ struct page *page = virt_to_page(addr);
+ if (!PageReserved(page)) { /* Is bootmem ? */
+ size_t table_size =
+ sizeof(struct page_cgroup) * PAGES_PER_SECTION;
+ free_pages_exact(addr, table_size);
+ }
+ }
+}
+#endif
+
static int __init_refok init_section_page_cgroup(unsigned long pfn)
{
struct page_cgroup *base, *pc;
@@ -147,17 +178,8 @@ static int __init_refok init_section_pag
nid = page_to_nid(pfn_to_page(pfn));
table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
- VM_BUG_ON(!slab_is_available());
- if (node_state(nid, N_HIGH_MEMORY)) {
- base = kmalloc_node(table_size,
- GFP_KERNEL | __GFP_NOWARN, nid);
- if (!base)
- base = vmalloc_node(table_size, nid);
- } else {
- base = kmalloc(table_size, GFP_KERNEL | __GFP_NOWARN);
- if (!base)
- base = vmalloc(table_size);
- }
+ base = alloc_page_cgroup(table_size, nid);
+
/*
* The value stored in section->page_cgroup is (base - pfn)
* and it does not point to the memory block allocated above,
@@ -189,16 +211,8 @@ void __free_page_cgroup(unsigned long pf
if (!ms || !ms->page_cgroup)
return;
base = ms->page_cgroup + pfn;
- if (is_vmalloc_addr(base)) {
- vfree(base);
- ms->page_cgroup = NULL;
- } else {
- struct page *page = virt_to_page(base);
- if (!PageReserved(page)) { /* Is bootmem ? */
- kfree(base);
- ms->page_cgroup = NULL;
- }
- }
+ free_page_cgroup(base);
+ ms->page_cgroup = NULL;
}
int __meminit online_page_cgroup(unsigned long start_pfn,
_
Patches currently in -mm which might be from mhocko@xxxxxxx are
origin.patch
memsw-remove-noswapaccount-kernel-parameter.patch
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