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percpu: move common parts out of pcpu_[de]populate_chunk()

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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@kernel.org>
This commit is contained in:
Tejun Heo 2014-09-02 14:46:01 -04:00
parent cdb4cba5a3
commit dca496451b
3 changed files with 31 additions and 40 deletions
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5
mm/percpu-km.c
View File

@ -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;
}

27
mm/percpu-vm.c
View File

@ -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)

39
mm/percpu.c
View File

@ -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);
}