+ multi-gen-lru-skip-cma-pages-when-they-are-not-eligible.patch added to mm-unstable branch

+ multi-gen-lru-skip-cma-pages-when-they-are-not-eligible.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: Multi-gen LRU: skip CMA pages when they are not eligible
has been added to the -mm mm-unstable branch.  Its filename is
     multi-gen-lru-skip-cma-pages-when-they-are-not-eligible.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/multi-gen-lru-skip-cma-pages-when-they-are-not-eligible.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Charan Teja Kalla <quic_charante@quicinc.com>
Subject: Multi-gen LRU: skip CMA pages when they are not eligible
Date: Wed, 9 Aug 2023 13:35:44 +0530

This patch is based on the commit 5da226dbfce3("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
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 |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/vmscan.c~multi-gen-lru-skip-cma-pages-when-they-are-not-eligible
+++ a/mm/vmscan.c
@@ -4944,7 +4944,7 @@ static bool sort_folio(struct lruvec *lr
 	}
 
 	/* 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;
_

Patches currently in -mm which might be from quic_charante@quicinc.com are

mm-madvise-fix-uneven-accounting-of-psi.patch
multi-gen-lru-skip-cma-pages-when-they-are-not-eligible.patch