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Wed, 2 Sep 2026 06:14:31 +0000 (GMT) Message-ID: <99b1121d-4277-4764-8c3a-b3f6d9a47ab0@linux.ibm.com> Date: Wed, 2 Sep 2026 11:44:30 +0530 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 12/17] x86/crash: Use num_possible_cpus() for elfcorehdr size To: Jinjie Ruan , catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, chenhuacai@kernel.org, kernel@xen0n.name, maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, chleroy@kernel.org, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, akpm@linux-foundation.org, baoquan.he@linux.dev, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, ruirui.yang@linux.dev, kees@kernel.org, thuth@redhat.com, gshan@redhat.com, jic23@kernel.org, james.morse@arm.com, ardb@kernel.org, leitao@debian.org, yeoreum.yun@arm.com, coxu@redhat.com, tangyouling@kylinos.cn, hbathini@linux.ibm.com, adityag@linux.ibm.com, ionut.nechita@windriver.com, liaoyuanhong@vivo.com, seanjc@google.com, fuqiang.wang@easystack.cn, makb@juniper.net, piliu@redhat.com, ebiggers@kernel.org, jbouron@amazon.com, mclapinski@google.com, me@linux.beauty, graf@amazon.com, bgwin@google.com, robh@kernel.org, takahiro.akashi@linaro.org, palmer@rivosinc.com, x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, ionut.nechita@windriver.com, ionut.nechita@windriver.com References: <20260826092541.3905933-1-ruanjinjie@huawei.com> <20260826092541.3905933-13-ruanjinjie@huawei.com> Content-Language: en-US From: Sourabh Jain In-Reply-To: <20260826092541.3905933-13-ruanjinjie@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=PPc/P/qC c=1 sm=1 tr=0 ts=6a97bed8 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VwQbUJbxAAAA:8 a=t7CeM3EgAAAA:8 a=i0EeH86SAAAA:8 a=GuF16Tie-v_x1sUWD14A:9 a=QEXdDO2ut3YA:10 a=FdTzh2GWekK77mhwV6Dw:22 X-Proofpoint-GUID: -IqDSf4F0FmOcL5Q3XCke1kr2YbwNiU1 X-Proofpoint-ORIG-GUID: KEmbHgCI7d9accZnEU6C4HI8egT2297V X-Proofpoint-Spam-Info: AW1haW4tMjYwOTAyMDA1MiBTYWx0ZWRfXz2AuISrj25WT 313Gdb0AKNnpWXJG+VJ95H+6kugoqcFZFisjytZwvIlWZ4y/Fd0LECR39q8SwiorgwEdibQqAYI wha1fu/nY7Cg/2E+X5ZeponvB/5ACF0= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTAyMDA1MiBTYWx0ZWRfXywQtEgYZYNk7 cAqCvDEwmxa2P2+rYvcX2LG0pVzZzBJixP7ujsGQlTI5b56QNy0fPGFIXZMj+cVXzQG7Txxj1tf JPp8WOZ9w+FSiQrwdM7zf1VfRstGyWgKWYR2YfDKwM/n6HHjI8mlm47PH8DAH3oBtlnst4y4EgI O2iserNtjKc0LQsu1b+WMjHcVjhP8zbdaOLjWjXP1WEClXE3IiAwoHGMsbCInx3NnX0P4B4fUVo Wp/rseWaWYYL+GNuKgYWDo8mENynCYHP2WrKTu0jPKTzj8UWdhrBRrhv7J5H4lBnON9qmao1sD4 A9USHe9k2hKpbjFcfVBv39HELqFwUfZZCoI0tb/+RLn8KRh9ZcxWC7wNKAkmeDd5w2s50jq6y2k bHRHLckUiG6jolF3WbzbH9sgRTtOC+kxTtJnqKEc8VkHs7KeRTij3Mfz+X9Os4dMFuci7HUb9A6 QIIMpPWSJS9r0ZIR48g== 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=2026-09-01_06,2026-09-01_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 adultscore=0 suspectscore=0 bulkscore=0 spamscore=0 priorityscore=1501 impostorscore=0 malwarescore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2609020052 Hello Jinjie, This patch makes the below patch redundant.. https://lore.kernel.org/all/20260826073527.21487-2-ionut.nechita@windriver.com/ I suggest dropping the first patch from the above series and including the second patch from that series in this patch series with the updated comment. - Sourabh Jain On 26/08/26 14:55, Jinjie Ruan wrote: > Use num_possible_cpus() instead of CONFIG_NR_CPUS to calculate the > elfcorehdr buffer size, matching what crash_prepare_elf64_headers() > already uses for the actual header content. > > This avoids over-allocation when the system has fewer possible CPUs > than the compile-time limit, and aligns x86 with PowerPC. > > Signed-off-by: Jinjie Ruan > --- > arch/x86/kernel/crash.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c > index a3bf786286d4..afe2aea19f47 100644 > --- a/arch/x86/kernel/crash.c > +++ b/arch/x86/kernel/crash.c > @@ -369,9 +369,9 @@ int crash_load_segments(struct kimage *image) > * maximum CPUs and maximum memory ranges. > */ > if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) > - pnum = 2 + CONFIG_NR_CPUS + CONFIG_CRASH_MAX_MEMORY_RANGES; > + pnum = 2 + num_possible_cpus() + CONFIG_CRASH_MAX_MEMORY_RANGES; > else > - pnum += 2 + CONFIG_NR_CPUS; > + pnum += 2 + num_possible_cpus(); > > if (pnum < (unsigned long)PN_XNUM) { > kbuf.memsz = elf64_phdr_size(pnum); > @@ -429,7 +429,7 @@ unsigned int arch_crash_get_elfcorehdr_size(void) > unsigned int sz; > > /* kernel_map, VMCOREINFO and maximum CPUs */ > - sz = 2 + CONFIG_NR_CPUS; > + sz = 2 + num_possible_cpus(); > if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) > sz += CONFIG_CRASH_MAX_MEMORY_RANGES; > sz *= sizeof(Elf64_Phdr);