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X-CSE-ConnectionGUID: 2EDjjlA1TzKvdS7E8QWlBw== X-CSE-MsgGUID: u6HWPZabT5ywlT9hmYP/lg== X-IronPort-AV: E=McAfee;i="6700,10204,11449"; a="54500871" X-IronPort-AV: E=Sophos;i="6.16,196,1744095600"; d="scan'208";a="54500871" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 May 2025 06:59:31 -0700 X-CSE-ConnectionGUID: tyWIxf77S+eTu8oioRT98w== X-CSE-MsgGUID: JkoSBStTTryxFNJEypUlRg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,196,1744095600"; d="scan'208";a="144859678" Received: from mgoodin-mobl2.amr.corp.intel.com (HELO [10.125.110.94]) ([10.125.110.94]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 May 2025 06:59:30 -0700 Message-ID: <304ea078-0f09-43d6-9dd2-264eb195e33e@intel.com> Date: Fri, 30 May 2025 06:59:29 -0700 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC v2 14/35] RPAL: enable page fault handling To: Bo Li , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, luto@kernel.org, kees@kernel.org, akpm@linux-foundation.org, david@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, peterz@infradead.org Cc: dietmar.eggemann@arm.com, hpa@zytor.com, acme@kernel.org, namhyung@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, irogers@google.com, adrian.hunter@intel.com, kan.liang@linux.intel.com, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, jannh@google.com, pfalcato@suse.de, riel@surriel.com, harry.yoo@oracle.com, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, duanxiongchun@bytedance.com, yinhongbo@bytedance.com, dengliang.1214@bytedance.com, xieyongji@bytedance.com, chaiwen.cc@bytedance.com, songmuchun@bytedance.com, yuanzhu@bytedance.com, chengguozhu@bytedance.com, sunjiadong.lff@bytedance.com References: From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/30/25 02:27, Bo Li wrote: > arch/x86/mm/fault.c | 271 ++++++++++++++++++++++++++++++++++++++++ > arch/x86/rpal/mm.c | 34 +++++ > arch/x86/rpal/service.c | 24 ++++ > arch/x86/rpal/thread.c | 23 ++++ > include/linux/rpal.h | 81 ++++++++---- > 5 files changed, 412 insertions(+), 21 deletions(-) I'm actually impressed again that you've managed to get this ported over to a newer kernel _and_ broken it up. But just taking a quick peek at _one_ patch, this is far, far below the standards by which we do kernel development. This appears to have simply copied chunks of existing code, hacked it to work with "RPAL" and then #ifdef'd. This is, unfortunately, copying and pasting at its worst. It creates dual paths that inevitably bit rot in some way and are hard to maintain. So, just to be clear: it's a full an unequivocal NAK from me on this series. This introduces massive change, massive security risk, can't possibly be backward compatible, has no users (well, maybe one) and the series is not put together in anything remotely resembling how we like to do kernel development. I'd appreciate if you could not cc me on future versions if you choose to go forward with this. But I urge you to stop now.