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Date: Wed, 21 Sep 2016 12:32:17 +0800
From: zijun_hu <zijun_hu@...o.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org, zijun_hu@....com,
tj@...nel.org, mingo@...nel.org, rientjes@...gle.com,
iamjoonsoo.kim@....com, mgorman@...hsingularity.net
Subject: [PATCH 4/5] mm/vmalloc.c: improve performance for pcpu_get_vm_areas()
From: zijun_hu <zijun_hu@....com>
improve performance for pcpu_get_vm_areas() in below aspects
- reduce the counter of vmap_areas overlay checkup loop to half
- find the previous or next one of a vamp_area by list_head but rbtree
Signed-off-by: zijun_hu <zijun_hu@....com>
---
include/linux/list.h | 11 +++++++++++
mm/internal.h | 6 ++++++
mm/memblock.c | 10 ++--------
mm/vmalloc.c | 55 +++++++++++++++++++++++++++++++++-------------------
4 files changed, 54 insertions(+), 28 deletions(-)
diff --git a/include/linux/list.h b/include/linux/list.h
index 5183138..23c3081 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -181,6 +181,17 @@ static inline int list_is_last(const struct list_head *list,
}
/**
+ * list_is_first - tests whether @list is the first entry in list @head
+ * @list: the entry to test
+ * @head: the head of the list
+ */
+static inline int list_is_first(const struct list_head *list,
+ const struct list_head *head)
+{
+ return list->prev == head;
+}
+
+/**
* list_empty - tests whether a list is empty
* @head: the list to test.
*/
diff --git a/mm/internal.h b/mm/internal.h
index 1501304..abbff7c 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -71,6 +71,12 @@ static inline void set_page_refcounted(struct page *page)
set_page_count(page, 1);
}
+/**
+ * check whether range [@s0, @e0) has intersection with [@s1, @e1)
+ */
+#define is_range_overlay(s0, e0, s1, e1) \
+ (((s1) >= (e0) || (s0) >= (e1)) ? false : true)
+
extern unsigned long highest_memmap_pfn;
/*
diff --git a/mm/memblock.c b/mm/memblock.c
index 483197e..b4c7d7c 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -85,20 +85,14 @@ static inline phys_addr_t memblock_cap_size(phys_addr_t base, phys_addr_t *size)
/*
* Address comparison utilities
*/
-static unsigned long __init_memblock memblock_addrs_overlap(phys_addr_t base1, phys_addr_t size1,
- phys_addr_t base2, phys_addr_t size2)
-{
- return ((base1 < (base2 + size2)) && (base2 < (base1 + size1)));
-}
-
bool __init_memblock memblock_overlaps_region(struct memblock_type *type,
phys_addr_t base, phys_addr_t size)
{
unsigned long i;
for (i = 0; i < type->cnt; i++)
- if (memblock_addrs_overlap(base, size, type->regions[i].base,
- type->regions[i].size))
+ if (is_range_overlay(base, base + size, type->regions[i].base,
+ type->regions[i].base + type->regions[i].size))
break;
return i < type->cnt;
}
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 2804224..5eeecc3 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -291,6 +291,22 @@ static unsigned long cached_align;
static unsigned long vmap_area_pcpu_hole;
+static inline struct vmap_area *next_vmap_area(struct vmap_area *va)
+{
+ if (list_is_last(&va->list, &vmap_area_list))
+ return NULL;
+ else
+ return list_next_entry(va, list);
+}
+
+static inline struct vmap_area *prev_vmap_area(struct vmap_area *va)
+{
+ if (list_is_first(&va->list, &vmap_area_list))
+ return NULL;
+ else
+ return list_prev_entry(va, list);
+}
+
static struct vmap_area *__find_vmap_area(unsigned long addr)
{
struct rb_node *n = vmap_area_root.rb_node;
@@ -1112,7 +1128,7 @@ void vm_unmap_ram(const void *mem, unsigned int count)
BUG_ON(!addr);
BUG_ON(addr < VMALLOC_START);
- BUG_ON(addr > VMALLOC_END);
+ BUG_ON(addr >= VMALLOC_END);
BUG_ON(!PAGE_ALIGNED(addr));
debug_check_no_locks_freed(mem, size);
@@ -2296,10 +2312,6 @@ void free_vm_area(struct vm_struct *area)
EXPORT_SYMBOL_GPL(free_vm_area);
#ifdef CONFIG_SMP
-static struct vmap_area *node_to_va(struct rb_node *n)
-{
- return n ? rb_entry(n, struct vmap_area, rb_node) : NULL;
-}
/**
* pvm_find_next_prev - find the next and prev vmap_area surrounding @end
@@ -2335,10 +2347,10 @@ static bool pvm_find_next_prev(unsigned long end,
if (va->va_end > end) {
*pnext = va;
- *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
+ *pprev = prev_vmap_area(va);
} else {
*pprev = va;
- *pnext = node_to_va(rb_next(&(*pprev)->rb_node));
+ *pnext = next_vmap_area(va);
}
return true;
}
@@ -2373,7 +2385,7 @@ static unsigned long pvm_determine_end(struct vmap_area **pnext,
while (*pprev && (*pprev)->va_end > addr) {
*pnext = *pprev;
- *pprev = node_to_va(rb_prev(&(*pnext)->rb_node));
+ *pprev = prev_vmap_area(*pnext);
}
return addr;
@@ -2413,31 +2425,34 @@ struct vm_struct **pcpu_get_vm_areas(const unsigned long *offsets,
struct vm_struct **vms;
int area, area2, last_area, term_area;
unsigned long base, start, end, last_end;
+ unsigned long start2, end2;
bool purged = false;
/* verify parameters and allocate data structures */
+ if (nr_vms < 1)
+ return NULL;
BUG_ON(offset_in_page(align) || !is_power_of_2(align));
- for (last_area = 0, area = 0; area < nr_vms; area++) {
+
+ last_area = nr_vms - 1;
+ BUG_ON(!IS_ALIGNED(offsets[last_area], align));
+ BUG_ON(!IS_ALIGNED(sizes[last_area], align));
+ for (area = 0; area < nr_vms - 1; area++) {
start = offsets[area];
end = start + sizes[area];
/* is everything aligned properly? */
- BUG_ON(!IS_ALIGNED(offsets[area], align));
- BUG_ON(!IS_ALIGNED(sizes[area], align));
+ BUG_ON(!IS_ALIGNED(start, align));
+ BUG_ON(!IS_ALIGNED(end, align));
/* detect the area with the highest address */
if (start > offsets[last_area])
last_area = area;
- for (area2 = 0; area2 < nr_vms; area2++) {
- unsigned long start2 = offsets[area2];
- unsigned long end2 = start2 + sizes[area2];
-
- if (area2 == area)
- continue;
+ for (area2 = area + 1; area2 < nr_vms; area2++) {
+ start2 = offsets[area2];
+ end2 = start2 + sizes[area2];
- BUG_ON(start2 >= start && start2 < end);
- BUG_ON(end2 <= end && end2 > start);
+ BUG_ON(is_range_overlay(start, end, start2, end2));
}
}
last_end = offsets[last_area] + sizes[last_area];
@@ -2507,7 +2522,7 @@ retry:
*/
if (prev && prev->va_end > base + start) {
next = prev;
- prev = node_to_va(rb_prev(&next->rb_node));
+ prev = prev_vmap_area(next);
base = pvm_determine_end(&next, &prev, align) - end;
term_area = area;
continue;
--
1.9.1
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