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Wysocki" , Daniel Lezcano , Christian Loehle , Anna-Maria Behnsen , Frederic Weisbecker , Ingo Molnar , Thomas Gleixner Cc: Mete Durlu , Ilya Leoshkevich , Christian Borntraeger , linux-s390 , linux-kernel Subject: [PATCH 1/5] s390/tick: Remove CIF_NOHZ_DELAY flag Date: Tue, 9 Jun 2026 09:52:09 +0200 Message-ID: <20260609075213.31094-2-meted@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260609075213.31094-1-meted@linux.ibm.com> References: <20260609075213.31094-1-meted@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=N4UZ0W9B c=1 sm=1 tr=0 ts=6a27c643 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=7PVU6fNTM30o4ork3uUA:9 X-Proofpoint-ORIG-GUID: Ex1-r6mXr7hXTa2ZG6sW_2rx-YixYmzT X-Proofpoint-GUID: Ex1-r6mXr7hXTa2ZG6sW_2rx-YixYmzT X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjA5MDA3MSBTYWx0ZWRfX61bXV4Zph5fm ojJzX9Y7atKNZEVjZrDauoYiho7ubOHujTJ4xdb/YK75q6G3I0kFTG1gzzHlbgcIekLUPwanuvX enOClJt9Mk4MjnagIg3X+lVVzS4VpVayjNs7gnMhZ8x1m144TdQXCeo9hPoGI2N8YaVUIH+o1Ut llwQ/2x81NVXb0iAnkDOeSPRrWetHcJ77WXqym0+EOZKZXQwMZd3M8rW/WzKbVe+pWSPgcYyeh/ 8cvTV7KYL2bBN2ckCjuY6BE5yis1OPs64hr61UfuXPgKv75tIDqVzbPWvwtlfypRKu9yN2rfLkV TDEzwo0Wk+Rg/lhCwEaxWJQ5NcJZ/IiexnTGA48ecMiLiATDqNQqNSLD2INKGXBbnluKY7Wjran +ekTQpfaTlw1+mL9PH90fcrEWXi+3lnTgB7oUlnVJBBJXE2y5b54Rc7GTuMLzEo5JyXF/A0qxJV gNlriBrAu5yM1UAJoYg== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-09_01,2026-06-09_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 malwarescore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 phishscore=0 impostorscore=0 adultscore=0 priorityscore=1501 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605210000 definitions=main-2606090071 Remove obsolete tick delay heuristic [1]. The upcoming cpuidle driver handles frequent sleep/wakeup cycles more effectively. [1] https://lore.kernel.org/all/20090929122533.402715150@de.ibm.com/ Suggested-by: Heiko Carstens Signed-off-by: Mete Durlu --- arch/s390/include/asm/processor.h | 4 ---- arch/s390/kernel/idle.c | 1 - arch/s390/kernel/irq.c | 4 ---- arch/s390/kernel/smp.c | 1 - 4 files changed, 10 deletions(-) diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h index 78195ee5e99f..3666198cc364 100644 --- a/arch/s390/include/asm/processor.h +++ b/arch/s390/include/asm/processor.h @@ -14,12 +14,10 @@ #include -#define CIF_NOHZ_DELAY 2 /* delay HZ disable for a tick */ #define CIF_ENABLED_WAIT 5 /* in enabled wait state */ #define CIF_MCCK_GUEST 6 /* machine check happening in guest */ #define CIF_DEDICATED_CPU 7 /* this CPU is dedicated */ -#define _CIF_NOHZ_DELAY BIT(CIF_NOHZ_DELAY) #define _CIF_ENABLED_WAIT BIT(CIF_ENABLED_WAIT) #define _CIF_MCCK_GUEST BIT(CIF_MCCK_GUEST) #define _CIF_DEDICATED_CPU BIT(CIF_DEDICATED_CPU) @@ -96,8 +94,6 @@ static __always_inline bool test_cpu_flag_of(int flag, int cpu) return test_bit(flag, &per_cpu(pcpu_devices, cpu).flags); } -#define arch_needs_cpu() test_cpu_flag(CIF_NOHZ_DELAY) - static inline void get_cpu_id(struct cpuid *ptr) { asm volatile("stidp %0" : "=Q" (*ptr)); diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c index 1f1b06b6b4ef..8c63f440da2e 100644 --- a/arch/s390/kernel/idle.c +++ b/arch/s390/kernel/idle.c @@ -42,7 +42,6 @@ void noinstr arch_cpu_idle(void) /* Wait for external, I/O or machine check interrupt. */ psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK; - clear_cpu_flag(CIF_NOHZ_DELAY); set_cpu_flag(CIF_ENABLED_WAIT); if (smp_cpu_mtid) stcctm(MT_DIAG, smp_cpu_mtid, (u64 *)&idle->mt_cycles_enter); diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c index d10a17e6531d..61d17954c34c 100644 --- a/arch/s390/kernel/irq.c +++ b/arch/s390/kernel/irq.c @@ -161,7 +161,6 @@ void noinstr do_io_irq(struct pt_regs *regs) if (from_idle) account_idle_time_irq(); - set_cpu_flag(CIF_NOHZ_DELAY); do { regs->tpi_info = get_lowcore()->tpi_info; if (get_lowcore()->tpi_info.adapter_IO) @@ -358,9 +357,6 @@ static irqreturn_t do_ext_interrupt(int irq, void *dummy) int index; ext_code.int_code = regs->int_code; - if (ext_code.code != EXT_IRQ_CLK_COMP) - set_cpu_flag(CIF_NOHZ_DELAY); - index = ext_hash(ext_code.code); rcu_read_lock(); hlist_for_each_entry_rcu(p, &ext_int_hash[index], entry) { diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 50bb499cf3e5..cd5ccbe3a18d 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -910,7 +910,6 @@ int __cpu_disable(void) cregs[6].val &= ~0xff000000UL; /* disable all I/O interrupts */ cregs[14].val &= ~0x1f000000UL; /* disable most machine checks */ __local_ctl_load(0, 15, cregs); - clear_cpu_flag(CIF_NOHZ_DELAY); return 0; } -- 2.54.0