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Commit dca49645 authored by Tejun Heo's avatar Tejun Heo
Browse files

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: default avatarTejun Heo <tj@kernel.org>
parent cdb4cba5

mm/percpu-km.c

+0 −5
Original line number Diff line number Diff line
@@ -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;

}

mm/percpu-vm.c

+1 −26
Original line number Diff line number Diff line
@@ -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)

mm/percpu.c

+30 −9
Original line number Diff line number Diff line
@@ -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;
@@ -802,7 +803,16 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved) 
area_found:

	spin_unlock_irqrestore(&pcpu_lock, flags);



	/* populate, map and clear the area */

	/* 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);
@@ -810,9 +820,15 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved) 
			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) {

		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);

	}