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b=GIXHsSRNDqHF1t56tZ2e9PPEkZAA7QhQ46XgrrEuMJ+dGkcBFbZoqdTg7CeChoO72 nunFwrKujraAZP1AdtQOBrqIYf2M91mFe2cY/TjhznFI1Q0MMPeJVRYR0l/vUiWHfa dfnPPbUortMBhwKjV975EsO1K1YhPFu9xEqBsKaLBqDIxLaOWcnxOnNIpd/oPYToAR ie9ukMlHY/IvfadI7oF/nciocoJjY5ab0gzJt1aw/6vdKAcsApD5MS0H+vawUlXJQC qsRjNjzy81USSLZHE1T2TYW5o9lJ4sY2EDHI8NuE2cOYtdmkKyXY+++JhGZgPQ9jay jx88RYsubK7Uw== Message-ID: <3149bc84-dd3a-43ba-826e-6364965fdafd@kernel.org> Date: Thu, 18 Jun 2026 10:21:04 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm/lruvec: trace LRU add drains and drain-all requests To: "Vlastimil Babka (SUSE)" , Shakeel Butt Cc: JP Kobryn , linux-mm@kvack.org, willy@infradead.org, usama.arif@linux.dev, akpm@linux-foundation.org, mhocko@suse.com, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, kasong@tencent.com, qi.zheng@linux.dev, baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, chrisl@kernel.org, shikemeng@huaweicloud.com, nphamcs@gmail.com, baoquan.he@linux.dev, youngjun.park@lge.com, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org References: <20260610195220.12403-1-jp.kobryn@linux.dev> <06122cae-e28b-4ded-a9dd-d380d31c5230@kernel.org> <1136baf3-3967-4202-9eaa-5fd667c235cf@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 295D4180011 X-Stat-Signature: j6eu5dnfi98zu68axs4kenjnckm8zu17 X-Rspam-User: X-HE-Tag: 1781770871-554197 X-HE-Meta: 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 87SiaKVT pipqYowILetxvxj8nUkrTTHmFFCycSV+msULY7J5QJW5H+H26BaX9teiEpCNwstMTquRkfYV6graa5GRbUQAOiDwdHj3YiHlZ1I3+J8VlrIifC6VGG0Hfe1QXaFzTfxeg+rogP6J+byFwZEBOeb6McKQDtQcbE6N8vE80Leiox7QbopGQL4hKLC08j/Gdufw+RjU35xvtzxYZKbCbaUckUPTu1ljr515oVLYOlCP8gqljJb72ypSjOfk+kxoK8DXv14pM Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 6/17/26 20:18, Vlastimil Babka (SUSE) wrote: > On 6/17/26 17:03, Shakeel Butt wrote: >> On Wed, Jun 17, 2026 at 01:11:16PM +0200, David Hildenbrand (Arm) wrote: >>> >>> Given that trace events can quickly become stable ABI [1], are we really sure we >>> want to add this? >> >> Yes, I think so as this is useful to get insights into lru cache draining. >> Trace events being stable or not is secondary IMHO. If in future we rearchitect >> the lru page handling where there is no cache draining anymore, we can make >> these a noops. > > Yeah and I don't recall ever that a change to a mm tracepoint would ever > break someone who'd complain and we'd have to revert it. Really? :) Read the context of the link I posted once more. -- Cheers, David