Multi-gen LRU: skip CMA pages when they are not eligible

This patch is based on the commit 5da226db("mm: skip CMA pages when
they are not available") which skips cma pages reclaim when they are not
eligible for the current allocation context.  In mglru, such pages are
added to the tail of the immediate generation to maintain better LRU
order, which is unlike the case of conventional LRU where such pages are
directly added to the head of the LRU list(akin to adding to head of the
youngest generation in mglru).

No observable issue without this patch on MGLRU, but logically it make
sense to skip the CMA page reclaim when those pages can't be satisfied for
the current allocation context.

Link: https://lkml.kernel.org/r/1691568344-13475-1-git-send-email-quic_charante@quicinc.com
Fixes: ac35a490 ("mm: multi-gen LRU: minimal implementation")
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/vmscan.c

@@ -4943,7 +4943,7 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, struct scan_c
 	}
 
 	/* ineligible */
-	if (zone > sc->reclaim_idx) {
+	if (zone > sc->reclaim_idx || skip_cma(folio, sc)) {
 		gen = folio_inc_gen(lruvec, folio, false);
 		list_move_tail(&folio->lru, &lrugen->folios[gen][type][zone]);
 		return true;