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Thu, 27 Nov 2025 19:13:01 -0800 (PST) From: Hongru Zhang X-Google-Original-From: Hongru Zhang To: akpm@linux-foundation.org, vbabka@suse.cz, david@kernel.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, rppt@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, Hongru Zhang Subject: [PATCH 3/3] mm: optimize free_area_empty() check using per-migratetype counts Date: Fri, 28 Nov 2025 11:12:42 +0800 Message-ID: X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Hongru Zhang Use per-migratetype counts instead of list_empty() helps reduce a few cpu instructions. Signed-off-by: Hongru Zhang --- mm/internal.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/internal.h b/mm/internal.h index 1561fc2ff5b8..7759f8fdf445 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -954,7 +954,7 @@ int find_suitable_fallback(struct free_area *area, unsi= gned int order, =20 static inline bool free_area_empty(struct free_area *area, int migratetype) { - return list_empty(&area->free_list[migratetype]); + return !READ_ONCE(area->mt_nr_free[migratetype]); } =20 /* mm/util.c */ --=20 2.43.0