percpu: move region iterations out of pcpu_[de]populate_chunk()
Previously, pcpu_[de]populate_chunk() were called with the range which
may contain multiple target regions in it and
pcpu_[de]populate_chunk() iterated over the regions. This has the
benefit of batching up cache flushes for all the regions; however,
we're planning to add more bookkeeping logic around [de]population to
support atomic allocations and this delegation of iterations gets in
the way.
This patch moves the region iterations out of
pcpu_[de]populate_chunk() into its callers - pcpu_alloc() and
pcpu_reclaim() - so that we can later add logic to track more states
around them. This change may make cache and tlb flushes more frequent
but multi-region [de]populations are rare anyway and if this actually
becomes a problem, it's not difficult to factor out cache flushes as
separate callbacks which are directly invoked from percpu.c.
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index edf7097..538998a 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -261,8 +261,8 @@
/**
* pcpu_populate_chunk - populate and map an area of a pcpu_chunk
* @chunk: chunk of interest
- * @off: offset to the area to populate
- * @size: size of the area to populate in bytes
+ * @page_start: the start page
+ * @page_end: the end page
*
* For each cpu, populate and map pages [@page_start,@page_end) into
* @chunk.
@@ -270,66 +270,43 @@
* CONTEXT:
* pcpu_alloc_mutex, does GFP_KERNEL allocation.
*/
-static int pcpu_populate_chunk(struct pcpu_chunk *chunk, int off, int size)
+static int pcpu_populate_chunk(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
{
- int page_start = PFN_DOWN(off);
- int page_end = PFN_UP(off + size);
- int free_end = page_start, unmap_end = page_start;
struct page **pages;
- int rs, re, rc;
pages = pcpu_get_pages(chunk);
if (!pages)
return -ENOMEM;
- /* alloc and map */
- pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
- rc = pcpu_alloc_pages(chunk, pages, rs, re);
- if (rc)
- goto err_free;
- free_end = re;
- }
+ if (pcpu_alloc_pages(chunk, pages, page_start, page_end))
+ return -ENOMEM;
- pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
- rc = pcpu_map_pages(chunk, pages, rs, re);
- if (rc)
- goto err_unmap;
- unmap_end = re;
+ if (pcpu_map_pages(chunk, pages, page_start, page_end)) {
+ pcpu_free_pages(chunk, pages, page_start, page_end);
+ return -ENOMEM;
}
pcpu_post_map_flush(chunk, page_start, page_end);
return 0;
-
-err_unmap:
- pcpu_pre_unmap_flush(chunk, page_start, unmap_end);
- pcpu_for_each_unpop_region(chunk, rs, re, page_start, unmap_end)
- pcpu_unmap_pages(chunk, pages, rs, re);
- pcpu_post_unmap_tlb_flush(chunk, page_start, unmap_end);
-err_free:
- pcpu_for_each_unpop_region(chunk, rs, re, page_start, free_end)
- pcpu_free_pages(chunk, pages, rs, re);
- return rc;
}
/**
* pcpu_depopulate_chunk - depopulate and unmap an area of a pcpu_chunk
* @chunk: chunk to depopulate
- * @off: offset to the area to depopulate
- * @size: size of the area to depopulate in bytes
+ * @page_start: the start page
+ * @page_end: the end page
*
* For each cpu, depopulate and unmap pages [@page_start,@page_end)
- * from @chunk. If @flush is true, vcache is flushed before unmapping
- * and tlb after.
+ * from @chunk.
*
* CONTEXT:
* pcpu_alloc_mutex.
*/
-static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk, int off, int size)
+static void pcpu_depopulate_chunk(struct pcpu_chunk *chunk,
+ int page_start, int page_end)
{
- int page_start = PFN_DOWN(off);
- int page_end = PFN_UP(off + size);
struct page **pages;
- int rs, re;
/*
* If control reaches here, there must have been at least one
@@ -342,13 +319,11 @@
/* unmap and free */
pcpu_pre_unmap_flush(chunk, page_start, page_end);
- pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
- pcpu_unmap_pages(chunk, pages, rs, re);
+ pcpu_unmap_pages(chunk, pages, page_start, page_end);
/* no need to flush tlb, vmalloc will handle it lazily */
- pcpu_for_each_pop_region(chunk, rs, re, page_start, page_end)
- pcpu_free_pages(chunk, pages, rs, re);
+ pcpu_free_pages(chunk, pages, page_start, page_end);
}
static struct pcpu_chunk *pcpu_create_chunk(void)