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[24.129.28.254]) by smtp.gmail.com with ESMTPSA id 00721157ae682-6f3e745648asm47410067b3.52.2024.12.28.10.49.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 28 Dec 2024 10:50:00 -0800 (PST) From: Yury Norov To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Michael Ellerman , Nicholas Piggin , Christophe Leroy , Naveen N Rao , Madhavan Srinivasan Cc: Yury Norov , Rasmus Villemoes Subject: [PATCH 04/14] powerpc/xmon: simplify xmon_batch_next_cpu() Date: Sat, 28 Dec 2024 10:49:36 -0800 Message-ID: <20241228184949.31582-5-yury.norov@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241228184949.31582-1-yury.norov@gmail.com> References: <20241228184949.31582-1-yury.norov@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The function opencodes for_each_cpu_wrap() macro. As a loop termination condition it uses cpumask_empty(), which is O(N), and it makes the whole algorithm O(N^2). Switching to for_each_cpu_wrap() simplifies the logic, and makes the algorithm linear. Signed-off-by: Yury Norov --- arch/powerpc/xmon/xmon.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index f4e841a36458..d7809f15dc68 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -1271,11 +1271,7 @@ static int xmon_batch_next_cpu(void) { unsigned long cpu; - while (!cpumask_empty(&xmon_batch_cpus)) { - cpu = cpumask_next_wrap(smp_processor_id(), &xmon_batch_cpus, - xmon_batch_start_cpu, true); - if (cpu >= nr_cpu_ids) - break; + for_each_cpu_wrap(cpu, &xmon_batch_cpus, xmon_batch_start_cpu) { if (xmon_batch_start_cpu == -1) xmon_batch_start_cpu = cpu; if (xmon_switch_cpu(cpu)) -- 2.43.0