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Date: Fri, 22 Aug 2014 12:53:09 -0400
From: Tejun Heo <tj@...nel.org>
To: akpm@...ux-foundation.org, cl@...ux-foundation.org
Cc: laijs@...fujitsu.com, linux-kernel@...r.kernel.org,
vgoyal@...hat.com, Tejun Heo <tj@...nel.org>
Subject: [PATCH 05/15] percpu: move common parts out of pcpu_[de]populate_chunk()
percpu-vm and percpu-km implement separate versions of
pcpu_[de]populate_chunk() and some part which is or should be common
are currently in the specific implementations. Make the following
changes.
* Allocate area clearing is moved from the pcpu_populate_chunk()
implementations to pcpu_alloc(). This makes percpu-km's version
noop.
* Quick exit tests in pcpu_[de]populate_chunk() of percpu-vm are moved
to their respective callers so that they are applied to percpu-km
too. This doesn't make any meaningful difference as both functions
are noop for percpu-km; however, this is more consistent and will
help implementing atomic allocation support.
Signed-off-by: Tejun Heo <tj@...nel.org>
---
mm/percpu-km.c | 5 -----
mm/percpu-vm.c | 27 +--------------------------
mm/percpu.c | 39 ++++++++++++++++++++++++++++++---------
3 files changed, 31 insertions(+), 40 deletions(-)
diff --git a/mm/percpu-km.c b/mm/percpu-km.c
index 89633fe..9a9096f 100644
--- a/mm/percpu-km.c
+++ b/mm/percpu-km.c
@@ -35,11 +35,6 @@
static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
{
- unsigned int cpu;
-
- for_each_possible_cpu(cpu)
- memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
-
return 0;
}
diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index d9e0b61..edf7097 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -265,7 +265,7 @@ static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
* @size: size of the area to populate in bytes
*
* For each cpu, populate and map pages [@page_start,@page_end) into
- * @chunk. The area is cleared on return.
+ * @chunk.
*
* CONTEXT:
* pcpu_alloc_mutex, does GFP_KERNEL allocation.
@@ -276,18 +276,8 @@ static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
int page_end = PFN_UP(off + size);
int free_end = page_start, unmap_end = page_start;
struct page **pages;
- unsigned int cpu;
int rs, re, rc;
- /* quick path, check whether all pages are already there */
- rs = page_start;
- pcpu_next_pop(chunk, &rs, &re, page_end);
- if (rs == page_start && re == page_end)
- goto clear;
-
- /* need to allocate and map pages, this chunk can't be immutable */
- WARN_ON(chunk->immutable);
-
pages = pcpu_get_pages(chunk);
if (!pages)
return -ENOMEM;
@@ -308,10 +298,6 @@ static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
}
pcpu_post_map_flush(chunk, page_start, page_end);
- bitmap_set(chunk->populated, page_start, page_end - page_start);
-clear:
- for_each_possible_cpu(cpu)
- memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
return 0;
err_unmap:
@@ -345,15 +331,6 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
struct page **pages;
int rs, re;
- /* quick path, check whether it's empty already */
- rs = page_start;
- pcpu_next_unpop(chunk, &rs, &re, page_end);
- if (rs == page_start && re == page_end)
- return;
-
- /* immutable chunks can't be depopulated */
- WARN_ON(chunk->immutable);
-
/*
* If control reaches here, there must have been at least one
* successful population attempt so the temp pages array must
@@ -372,8 +349,6 @@ static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
pcpu_free_pages(chunk, pages, rs, re);
-
- bitmap_clear(chunk->populated, page_start, page_end - page_start);
}
static struct pcpu_chunk *pcpu_create_chunk(void)
diff --git a/mm/percpu.c b/mm/percpu.c
index 2139e30..12b0049 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -709,7 +709,8 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
static int warn_limit = 10;
struct pcpu_chunk *chunk;
const char *err;
- int slot, off, new_alloc;
+ int slot, off, new_alloc, cpu;
+ int page_start, page_end, rs, re;
unsigned long flags;
void __percpu *ptr;
@@ -802,17 +803,32 @@ restart:
area_found:
spin_unlock_irqrestore(&pcpu_lock, flags);
- /* populate, map and clear the area */
- if (pcpu_populate_chunk(chunk, off, size)) {
- spin_lock_irqsave(&pcpu_lock, flags);
- pcpu_free_area(chunk, off);
- err = "failed to populate";
- goto fail_unlock;
+ /* populate if not all pages are already there */
+ page_start = PFN_DOWN(off);
+ page_end = PFN_UP(off + size);
+
+ rs = page_start;
+ pcpu_next_pop(chunk, &rs, &re, page_end);
+
+ if (rs != page_start || re != page_end) {
+ WARN_ON(chunk->immutable);
+
+ if (pcpu_populate_chunk(chunk, off, size)) {
+ spin_lock_irqsave(&pcpu_lock, flags);
+ pcpu_free_area(chunk, off);
+ err = "failed to populate";
+ goto fail_unlock;
+ }
+
+ bitmap_set(chunk->populated, page_start, page_end - page_start);
}
mutex_unlock(&pcpu_alloc_mutex);
- /* return address relative to base address */
+ /* clear the areas and return address relative to base address */
+ for_each_possible_cpu(cpu)
+ memset((void *)pcpu_chunk_addr(chunk, cpu, 0) + off, 0, size);
+
ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
kmemleak_alloc_percpu(ptr, size);
return ptr;
@@ -903,7 +919,12 @@ static void pcpu_reclaim(struct work_struct *work)
spin_unlock_irq(&pcpu_lock);
list_for_each_entry_safe(chunk, next, &todo, list) {
- pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
+ int rs = 0, re;
+
+ pcpu_next_unpop(chunk, &rs, &re, PFN_UP(pcpu_unit_size));
+ if (rs || re != PFN_UP(pcpu_unit_size))
+ pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
+
pcpu_destroy_chunk(chunk);
}
--
1.9.3
--
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