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([2a02:3037:629:fd15:33bf:191b:faa5:2818]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a774a4031sm33051185e9.2.2026.04.28.06.05.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2026 06:05:30 -0700 (PDT) From: Abd-Alrhman Masalkhi To: song@kernel.org, yukuai@fnnas.com Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org, Abd-Alrhman Masalkhi Subject: [PATCH v2] md: skip redundant raid_disks update when value is unchanged Date: Tue, 28 Apr 2026 15:05:24 +0200 Message-ID: <20260428130524.448063-1-abd.masalkhi@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Calling update_raid_disks() with the same value as the current one can trigger unnecessary work. For example, RAID1 will reallocate resources such as the mempool for r1bio. Signed-off-by: Abd-Alrhman Masalkhi --- drivers/md/md.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/md/md.c b/drivers/md/md.c index ac71640ff3a8..21b8ad17685f 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -4409,9 +4409,10 @@ raid_disks_store(struct mddev *mddev, const char *buf, size_t len) err = mddev_suspend_and_lock(mddev); if (err) return err; - if (mddev->pers) - err = update_raid_disks(mddev, n); - else if (mddev->reshape_position != MaxSector) { + if (mddev->pers) { + if (n != mddev->raid_disks) + err = update_raid_disks(mddev, n); + } else if (mddev->reshape_position != MaxSector) { struct md_rdev *rdev; int olddisks = mddev->raid_disks - mddev->delta_disks; -- 2.43.0