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.c b/mm/percpu.c
index 6087384..fe5de97 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -807,20 +807,17 @@
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) {
+ pcpu_for_each_unpop_region(chunk, rs, re, page_start, page_end) {
WARN_ON(chunk->immutable);
- if (pcpu_populate_chunk(chunk, off, size)) {
+ if (pcpu_populate_chunk(chunk, rs, re)) {
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);
+ bitmap_set(chunk->populated, rs, re - rs);
}
mutex_unlock(&pcpu_alloc_mutex);
@@ -919,12 +916,12 @@
spin_unlock_irq(&pcpu_lock);
list_for_each_entry_safe(chunk, next, &todo, list) {
- int rs = 0, re;
+ int rs, 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_for_each_pop_region(chunk, rs, re, 0, pcpu_unit_pages) {
+ pcpu_depopulate_chunk(chunk, rs, re);
+ bitmap_clear(chunk->populated, rs, re - rs);
+ }
pcpu_destroy_chunk(chunk);
}