staging: ion: shrink page-pool by page unit

This patch shrink page-pool by page unit.

The system shrinker calls ion_heap_shrink_count() to get nr_to_scan,
and pass it to ion_heap_shrink_scan().
The problem is the return value of ion_heap_shrink_count() is the number
of pages but ion_system_heap_shrink(), which is called by
ion_heap_shrink_scan(), gets the number of chunk.

The main root of this is that ion_page_pool_shrink() returns page count
via ion_page_pool_total() if it have to check pool size. But it frees
chunks of pages if it have to free pools.

This patch first fix ion_page_pool_shrink() to count only pages,
not chunks. And then ion_system_heap_shrink() to work on pages.

Signed-off-by: Gioh Kim <gioh.kim@lge.com>
Reviewed-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/android/ion/ion_page_pool.c b/drivers/staging/android/ion/ion_page_pool.c
index 4b88f11e52d372ff3b33c5d448852fcddfeaac5c..19ad3aba499ae579889892e6c6168833f4c0851f 100644 (file)
--- a/drivers/staging/android/ion/ion_page_pool.c
+++ b/drivers/staging/android/ion/ion_page_pool.c
@@ -116,7 +116,7 @@ static int ion_page_pool_total(struct ion_page_pool *pool, bool high)
 int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask,
                                int nr_to_scan)
 {
-       int freed;
+       int freed = 0;
        bool high;
 
        if (current_is_kswapd())
@@ -127,7 +127,7 @@ int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask,
        if (nr_to_scan == 0)
                return ion_page_pool_total(pool, high);
 
-       for (freed = 0; freed < nr_to_scan; freed++) {
+       while (freed < nr_to_scan) {
                struct page *page;
 
                mutex_lock(&pool->mutex);
@@ -141,6 +141,7 @@ int ion_page_pool_shrink(struct ion_page_pool *pool, gfp_t gfp_mask,
                }
                mutex_unlock(&pool->mutex);
                ion_page_pool_free_pages(pool, page);
+               freed += (1 << pool->order);
        }
 
        return freed;

diff --git a/drivers/staging/android/ion/ion_system_heap.c b/drivers/staging/android/ion/ion_system_heap.c
index da2a63c0a9ba5896e96652356c97d718aa761c1f..7a7a9a047230889a8d0883e68364609968c875a0 100644 (file)
--- a/drivers/staging/android/ion/ion_system_heap.c
+++ b/drivers/staging/android/ion/ion_system_heap.c
@@ -212,14 +212,26 @@ static int ion_system_heap_shrink(struct ion_heap *heap, gfp_t gfp_mask,
 {
        struct ion_system_heap *sys_heap;
        int nr_total = 0;
-       int i;
+       int i, nr_freed;
+       int only_scan = 0;
 
        sys_heap = container_of(heap, struct ion_system_heap, heap);
 
+       if (!nr_to_scan)
+               only_scan = 1;
+
        for (i = 0; i < num_orders; i++) {
                struct ion_page_pool *pool = sys_heap->pools[i];
 
-               nr_total += ion_page_pool_shrink(pool, gfp_mask, nr_to_scan);
+               nr_freed = ion_page_pool_shrink(pool, gfp_mask, nr_to_scan);
+               nr_total += nr_freed;
+
+               if (!only_scan) {
+                       nr_to_scan -= nr_freed;
+                       /* shrink completed */
+                       if (nr_to_scan <= 0)
+                               break;
+               }
        }
 
        return nr_total;