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Mon, 17 Nov 2025 18:33:59 GMT Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 177362004B; Mon, 17 Nov 2025 18:33:59 +0000 (GMT) Received: from smtpav07.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DEBB920040; Mon, 17 Nov 2025 18:33:55 +0000 (GMT) Received: from [9.39.23.49] (unknown [9.39.23.49]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 17 Nov 2025 18:33:55 +0000 (GMT) Message-ID: <469c97cb-5ea1-4c2b-a70f-b1a6febf70df@linux.ibm.com> Date: Tue, 18 Nov 2025 00:03:54 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5] crash: export crashkernel CMA reservation to userspace To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Aditya Gupta , Baoquan he , Dave Young , Hari Bathini , Jiri Bohac , Madhavan Srinivasan , Mahesh J Salgaonkar , Pingfan Liu , "Ritesh Harjani (IBM)" , Shivang Upadhyay , Vivek Goyal , linuxppc-dev@lists.ozlabs.org, kexec@lists.infradead.org References: <20251117041905.1277801-1-sourabhjain@linux.ibm.com> <20251117094211.f8b4426ddda3bc0db5a62624@linux-foundation.org> Content-Language: en-US From: Sourabh Jain In-Reply-To: <20251117094211.f8b4426ddda3bc0db5a62624@linux-foundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: CU9iESYN2j67vAEv2SgazOoBXgPDzaQZ X-Proofpoint-ORIG-GUID: pxnzCu9taJxuT8G2Bw21OV8xLzu6ZmTS X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTE1MDAzMiBTYWx0ZWRfX27fIVSon0c6o UhN7VIJqtR8X3Mll3WY0QUrGaxzD3eoEtbFLhPJP4xwmtisCcKFGgUTtpJFYFNCuz8lf8PriBwf Mo/rT53XUKk0VG3KPLrYJQBmmAUS+LkMpqB5MZIdiHhU3g9cJ9i3x6DI6vpdneuc1Ax9A37PAhW jbgBAvIt23EnO+qkzXEfmuB0oieL+72N0YJ1lZUkit9jf2cPx7EzjkyHl9HGs3+dA9Q3KJANyRt kRxGDqsSZQPDM7yR6rUmru+g7ZN5mNdTzenEcOob2W5hsyzNv+YDsCzIltQgDNSusGPKfXOhwKx cRMIK2OaYKyHSzi8LzsGL1xB3TZn1WHiSqQOh2N51evC/vDLGqQuD/yNkIGHXvPhJeJwbS10Z4G 0fKNeNrEdaZy3dB3H7icpuJe0t5wdg== X-Authority-Analysis: v=2.4 cv=SvOdKfO0 c=1 sm=1 tr=0 ts=691b6a9c cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=0l8sKcWMKP3lnFByZlwA:9 a=QEXdDO2ut3YA:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-17_03,2025-11-13_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 lowpriorityscore=0 spamscore=0 clxscore=1015 suspectscore=0 phishscore=0 adultscore=0 bulkscore=0 impostorscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511150032 On 17/11/25 23:12, Andrew Morton wrote: > On Mon, 17 Nov 2025 09:49:05 +0530 Sourabh Jain wrote: > >> Add a sysfs entry /sys/kernel/kexec/crash_cma_ranges to expose all >> CMA crashkernel ranges. >> >> This allows userspace tools configuring kdump to determine how much >> memory is reserved for crashkernel. If CMA is used, tools can warn >> users when attempting to capture user pages with CMA reservation. >> >> The new sysfs hold the CMA ranges in below format: >> >> cat /sys/kernel/kexec/crash_cma_ranges >> 100000000-10c7fffff >> >> There are already four kexec and kdump sysfs entries under /sys/kernel. >> Adding more entries there would clutter the directory. To avoid this, >> the new crash_cma_ranges sysfs entry is placed in a new kexec node under >> /sys/kernel/. > I suggest not creating /sys/kernel/kexec in this patch. > > Moving everything into a new /sys/kernel/kexec is a separate patchset > and a separate concept and it might never be merged - it changes ABI! > > So let's put crash_cma_ranges in /sys/kernel and move it to > /sys/kernel/kexec within the other patchset. Yeah sure. I will send the patches accordingly. Thanks, Sourabh Jain