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Sat, 15 Nov 2025 16:09:46 GMT Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AAE2020043; Sat, 15 Nov 2025 16:09:46 +0000 (GMT) Received: from smtpav04.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1BE5C20040; Sat, 15 Nov 2025 16:09:43 +0000 (GMT) Received: from [9.39.19.249] (unknown [9.39.19.249]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Sat, 15 Nov 2025 16:09:42 +0000 (GMT) Message-ID: Date: Sat, 15 Nov 2025 21:39:40 +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 v4 0/5] kexec: reorganize sysfs interface and add new kexec sysfs 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 , Sourabh Jain , Vivek Goyal , linuxppc-dev@lists.ozlabs.org, kexec@lists.infradea References: <20251114051504.614937-1-sourabhjain@linux.ibm.com> <20251114152550.ac2dd5e23542f09c62defec7@linux-foundation.org> Content-Language: en-US From: Sourabh Jain In-Reply-To: <20251114152550.ac2dd5e23542f09c62defec7@linux-foundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: 9n2C37ByZa5_ROB86UWmrby0MJwyrkHq X-Authority-Analysis: v=2.4 cv=YqwChoYX c=1 sm=1 tr=0 ts=6918a5d1 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=gKol05NBOib2xTfy92sA:9 a=QEXdDO2ut3YA:10 a=cPQSjfK2_nFv0Q5t_7PE:22 X-Proofpoint-ORIG-GUID: dVXF1qsjVYQdl2pEdgoUWq-DA0XY4uRS X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTE1MDAzMiBTYWx0ZWRfX+NLnRL/ZBXtZ Modz/yk8C4zjyeQsioo26dAgJHIVW6iKj5BonU4x+LeabDbs6qOnkD+LyRo2JtF0r5phrOUYiCh TVgna6iEjkOWx4ACZX39LKuD7CXpGAxTIsWyk98BQ4Axn++4DbEWK2pO7uMA1a6Oiub/KmhUkIl HLEwhA8+LkrOJcZ9x9fgA/bvGjxpY/ZsKFpy8KdudPOnQsWzqB+y/evMHcgrAEvgAr3avs26e3j f1bovNF3bBewnE/vE/9dnmFCzL0ddEdV/YJWE4K8Mdci6ElL8ah13uiq0Kl2gyXbjKV30GiuHl2 9yAPgdiMMwcrkMrq4N02OOhAztt1DvkLX0UOkeDZ7NnvD/qK+MKd5bLvUMZ0w/YGOzC9KbSBdtN d4kyhbnWmPJklVVn0djxR6TN/Bqhew== 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=2025-11-15_05,2025-11-13_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 impostorscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 adultscore=0 bulkscore=0 phishscore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511150032 On 15/11/25 04:55, Andrew Morton wrote: > On Fri, 14 Nov 2025 10:44:59 +0530 Sourabh Jain wrote: > >> All existing kexec and kdump sysfs entries are moved to a new location, >> /sys/kernel/kexec, to keep /sys/kernel/ clean and better organized. >> Symlinks are created at the old locations for backward compatibility and >> can be removed in the future [02/05]. >> >> While doing this cleanup, missing ABI documentation for the old sysfs >> interfaces is added, and those entries are marked as deprecated >> [01/05 and 03/05]. New ABI documentation is also added for the >> reorganized interfaces. [04/05] >> >> Along with this reorganization, a new sysfs file, >> /sys/kernel/kexec/crash_cma_ranges, is introduced to export crashkernel >> CMA reservation details to user space [05/05]. This helps tools >> determine the total crashkernel reserved memory and warn users that >> capturing user pages while CMA is reserved may cause incomplete or >> unreliable dumps. > Patchset does three unrelated things in remarkably random order. > > 1: Document existing stuff > > Great, thanks, in it goes. > > 2: export crashkernel CMA reservation to userspace > > Well, OK, probably reasonable, didn't look closely. > > 3: Alter longstanding userspace ABI with deprecation plan > > Whoa, tricky, needs careful consideration. > > > So can we please prepare and consider this material in three separate > patchsets? In the above order, I suggest. Yeah sure. The question here is where to add the new CMA reservation sysfs. Should I place it under /sys/kernel/ or create /sys/kernel/kexec and add it there? Since I am proposing that all kexec sysfs entries move to the new location /sys/kernel/kexec, I am going to add the CMA reservation sysfs under /sys/kernel/kexec to avoid creating a symlink for this entry later in my third patch series. - Sourabh