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Mon, 12 Oct 2026 12:41:28 +0000 (GMT) Received: from li-008a6a4c-3549-11b2-a85c-c5cc2836eea2.ibm.com (unknown [9.224.92.206]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTPS; Mon, 12 Oct 2026 12:41:28 +0000 (GMT) Date: Mon, 12 Oct 2026 14:41:27 +0200 From: Alexander Gordeev To: Heiko Carstens Cc: Sven Schnelle , Vasily Gorbik , Christian Borntraeger , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: Re: [PATCH 1/4] s390/percpu: Use asm_inline for arch_this_cpu_add() Message-ID: <2af61c70-bfa9-48d3-a197-41eac0b9c5aa-agordeev@linux.ibm.com> References: <20261012114249.2898572-1-hca@linux.ibm.com> <20261012114249.2898572-2-hca@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261012114249.2898572-2-hca@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYxMDEyMDA0OCBTYWx0ZWRfX93K1cxr2ApH+ WiMl3kLtKGhgDIbYE2GNwv67BlYh/TZzqpULet/Lo51MtSPzhcH+GxGZER+Qeojc7O9ZmxZH3My lMvXtW3Z99yND3gQlZ5dp2+Q8WUfAMg= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDEyMDA0OCBTYWx0ZWRfXxAmVjQF3+4z3 XiBkw91xh/VJAxtU0tOoy8FU/PsfWVNkQORPnSFCi+9vnVcfYZoPRo5ldjbJvFN6J1b/tNX+vm8 y+3cbG76GRyZs6AvLdeduyQYRoxLo+AHt1KPzYIX1P/27uD1oVr56trhZLriLGC3Lvme+UedJ3i 3LR9WGYAe+VIzw5RG1AVFtCr0QqN7k6AwcRGhqICAAYxdheixExDFCqwL6YCPxikSDWMYZoDzgb mRKnwnqJcMfJkDW+n+M06dti2o9SvGJ6HwMaqQfmwl7GiwSLewXaXSN1U48mvy0bhrvU2kX1Wyl i617nZBW9K+DeQ9c6AotdozvPVahz7Km60UFl+0VrKS/PXgZ+NbknTaSCV+XGzvedJgCd3GoA2c aiwya5Mr56YkP5fDx6R0yH0H7XjIRk6Mg+OJIUp2bzS8+N1o63mvWUG4RMfEW+PpMj/Jc7xJOif dnedyMNebQvgZYwqJyA== X-Authority-Analysis: v=2.4 cv=E6pYNqdl c=1 sm=1 tr=0 ts=6accd57d cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=kj9zAlcOel0A:10 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VnNF1IyMAAAA:8 a=x59IMPMvzmwHi_HZdScA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-ORIG-GUID: PmBHCKBR01ZzxpKYAL37ykbft33EnUn7 X-Proofpoint-GUID: PmBHCKBR01ZzxpKYAL37ykbft33EnUn7 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-10-12_04,2026-10-09_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 phishscore=0 clxscore=1015 bulkscore=0 priorityscore=1501 spamscore=0 adultscore=0 suspectscore=0 malwarescore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610080000 definitions=main-2610120048 On Mon, Oct 12, 2026 at 01:42:46PM +0200, Heiko Carstens wrote: > When converting to preemptible percpu operations the arch_this_cpu_add() > inline assemblies were not converted to use asm_inline instead of a plain > asm statement. > > With all the macro usage the inline assemblies grow significantly, and > the compiler may decide to not inline even small functions. This can be > observed with gcc16 and a defconfig build where many calls to > __srcu_read_lock_fast() are not inlined anymore, even though it is > basically only a this_cpu_inc(). > > Use asm_inline to address this. > > Fixes: 18ec6c5d7ec6 ("s390/percpu: Use new percpu code section for arch_this_cpu_add()") > Signed-off-by: Heiko Carstens > --- > arch/s390/include/asm/percpu.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) Acked-by: Alexander Gordeev