Revert "BACKPORT: FROMGIT: mm: skip CMA pages when they are not available"

This reverts commit 0a52bf2972.

To be replaced with upstream version.

Bug: 288383787
Bug: 291719697
Change-Id: I2ff5d9cd8bb1e827cd5e233aa97325d026cec27f
Signed-off-by: Kalesh Singh <kaleshsingh@google.com>

mm/vmscan.c

@@ -1950,25 +1950,6 @@ static __always_inline void update_lru_sizes(struct lruvec *lruvec,
 
 }
 
-#ifdef CONFIG_CMA
-/*
- * It is waste of effort to scan and reclaim CMA pages if it is not available
- * for current allocation context. Kswapd can not be enrolled as it can not
- * distinguish this scenario by using sc->gfp_mask = GFP_KERNEL
- */
-static bool skip_cma(struct page *page, struct scan_control *sc)
-{
-       return !current_is_kswapd() &&
-                       gfp_migratetype(sc->gfp_mask) != MIGRATE_MOVABLE &&
-                       get_pageblock_migratetype(page) == MIGRATE_CMA;
-}
-#else
-static bool skip_cma(struct page *page, struct scan_control *sc)
-{
-       return false;
-}
-#endif
-
 /*
  * Isolating page from the lruvec to fill in @dst list by nr_to_scan times.
  *
@@ -2015,8 +1996,7 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
 		nr_pages = compound_nr(page);
 		total_scan += nr_pages;
 
-		if (page_zonenum(page) > sc->reclaim_idx ||
-				skip_cma(page, sc)) {
+		if (page_zonenum(page) > sc->reclaim_idx) {
 			nr_skipped[page_zonenum(page)] += nr_pages;
 			move_to = &pages_skipped;
 			goto move;