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Sun, 12 Apr 2026 12:04:50 -0700 (PDT) From: Liew Rui Yan To: sj@kernel.org Cc: aethernet65535@gmail.com, damon@lists.linux.dev, linux-mm@kvack.org Subject: Re: (sashiko review) [PATCH v4 1/2] mm/damon/lru_sort: validate min_region_size to be power of 2 Date: Mon, 13 Apr 2026 03:04:55 +0800 Message-ID: <20260412190455.6685-1-aethernet65535@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260411153821.95491-1-sj@kernel.org> References: <20260411153821.95491-1-sj@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Stat-Signature: j1uymzb5676nc7dthga8ebedgpbqty6p X-Rspamd-Queue-Id: 28C9420011 X-Rspam-User: X-HE-Tag: 1776020691-417267 X-HE-Meta: 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 33HNb2vn gTPCCBqSSwJHzrF1BfGfjJr7E7WF12VTMljZOrHTo51X3SyNPPOEbrefhc/Zoo1qmYt/NeDKChx4HcpI4iA5ASEkzAUS5yFNiPuxCepW+7XpTQ5izo5AZhu1wj8UHDvl+9/gjXJTzSLpU5i/Xh7rLwIqPt5jo8AYWJQ2dy34YuChLJT3dCm/aUvJ+JKRUh5Ql3/uz/pYlsRVwhKFx4Zwa+nwhNf2NVrjAEgSQa/LZWi+4xK1VeVIQPOeqaboyxhRPLMez3WPakeHdudoafwyKxXK+/hjSzGwMauJ+wJmK8vXwrz6nn3YxQowWuz1elAA+Spr7aOS+O31pEUqkziOSLYgtaYnTAv4M2b8MbWcUcGeROcY5vgq0JaeVMRbVslPRyPsPN7xWAAqnmEpa+o9cbSd3P+RWdFl/KZ7teRfrcYeJlDNY6N6YtCAld35q8TNCCCXTgLrRf447C8uN1Ya5MpE/IeDQs+NGQg4rqFVB0Wgbyz8= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi SeongJae, Thank you for your detailed explanation and for being patient with me. I sincerely apologize for the confusion and the extra workload my unclear communication has caused you. It was never my intention to hide context or game the system; I simply misjudged the priorities and failed to provide the full picture. I want to continue contributing to DAMON. I truly enjoy working on it, and I'm grateful for the opportunity. On Sat, 11 Apr 2026 08:38:21 -0700 SeongJae Park wrote: > > Thank you for sharing these. But seems even this context is incomplete from my > perspective... > > The Real Context > ---------------- > > The real start of the context is probably the question [1] that you asked on > 2026-03-18. At that time, we found committing wrong parameters stops DAMON > without an user-visible error. We agreed DAMON being killed is no problem but > the absence of user-visible error is a minor user experience problem that > better to be improved. So you planned to make the user experience improvement. You're right - that question was the real starting point. Back then, I hadn't yet realized that an unexpectedly terminated kdamond cannot be restarted. After that discussion, I started working on synchronous commit patch [1]. > > Apparently series A is the followup of that. The first version was posted on > 2026-03-26, according to the changelog of this patch series. I can show I was > saying the patch was confusing on the thread. Series A came from a Sashiko review [2] that appeared while I was working on that synchronous commit patch. It [3] was a new, separate issue. > > While the review of the confusing series A was ongoing, you posted [3] the RFC > of series B on 2026-03-31. This patch reported one important finding: the > silent DAMON stop is not just a minor user experience issue but a serious bug > because it cannot be started again. I discovered the "kdamond cannot restart" problem by accident while testing other things. That's why I treated it as a separate issue from Series A, not as something directly related. > > And this made things much more confusing. There are multiple ways to trigger > the issue. Wrong addr_unit commit is just one of the ways. We discussed the > way to fix the real issue. So, by looking back this, I think you should > prioritized series B from the point, or make suer series A is only for the > minor user experience improvement. Or asked me what to prioritize. You didn't > and I missed the fact that you are also working on series A. Here's what happened in my head, and I'm sorry I didn't say it loud at the time: After you advised me to slow down [4], I thought you preferred me to focus on one series at a time. Since Series A looked closer to merge, I decided to finish it first, then move to Series B. I should have asked you what to prioritize instead of assuming. That was my mistake. > > But you just continued posting new versions of series A. I was wrongly > thinking that is still the minor user experience improvement. I still think > the patches were implicitly saying so. I'm not sure if it was intentional or > not. But definitely it was confusing me. On 2026-04-02, I started feeling I'm > missing some of the contexts, and asked you more clarification of user impacts > [4] and full history [5]. You posted v3 [6] right after I asked the question, > even without answering the question. Only from this point it became clear > sereis A is not just a minor user experience improvement but a critical bug > fix. Now I think you should clarify this can also fix one trigger point of the > critical bug but the real fix is work in progress, and this is till only a > minor user experience improvement. But because you didn't, and my poor memory > is volatile, at this point I was thinking this all the work you are doing for > the series B-exposed bug. Regarding your "[4][5]": When you asked about Cc:stable@, I got excited and focused on figuring out the Fixes tag and stable rules. When you asked if I had other patches, I thought you meant the older "addr_unit power-of-2 validation" patch [3] from before Series A. I didn't realize you were asking about all my in-progress work. I'm sorry for the confusion. > > In the response to the sashiko review on this thread, therefore, I was thinking > you are thinking the wrong addr_unit commit is the only way to trigger the bug. > I didn't want to ask you to work from the beginning to fix the entire bug, so I > was saying fixing the real bug for all exploit points is out of the scope of > this bug. > > But now it is turned out that you were aware of the other ways to trigger the > bug, and didn't transparentl and explicitly exposing that. To be honest, I only knew about the 'addr_unit' trigger. I was vaguely aware that memory allocation failures could also cause termination, but I never reproduced them or investigated further. I should have told you this earlier. > > So I withdraw what I told on the reply to the sashiko review. And appreciate > sashiko developers again for giving us a chance to finding this. > > Next Steps > ---------- > > So, what to do? Please prioritize series B, if you still willing to do. It is > ok to keep doing series A, but only as the minor user experience improvement. > Clearly explain the whole context you are aware of. Don't Cc stable@ for > series A, as it is only an incomplete fix of it. The fix of the one trigger > point is just a side effect. Yes, I absolutely want to continue contributing to DAMON. I realize most of this confusion came from me misinterpreting your words or making assumptions without asking. So this time, I want to be explicit: 1. I will remove the Cc stable@ 2. Since you suggested prioritizing Series B, would you prefer me to send a revised v5 of Series A now, or should I wait until Series B is settled to avoid more noise in your inbox? 3. I will focus on Series B starting now. > > And For Future Contributions > ---------------------------- > > Liew, I really appreciate your contributions. You found and shared important > DAMON bugs. But apparently your communication has many rooms to improve, at > least for poort DAMON maintainer who have to work with only limited resources > including the poort and volatile memory. I find I was asking clarifications to > your mails multiple times. I have to say it was even frustrating sometimes and > definitely took quite amount of my resource. Meanwhile, from my uncautiously > biased perspective, you were only adding more traffic and confusions. I'm very sorry for the trouble I caused. Moving forward, I will ask before assuming, and I will make sure my intentions are clear. > > This makes me disappointed and even suspect your intention... I really hate > myself suspecting someone. But we are in the world of bad actors that now > gained the power of AI. We actually had a suspicious case from DAMON > contributors recently, do you remember? Yes, I remember the Josh Law case. I am not a bot. I have no intention of gaming contributions or harming DAMON. I just want to do real work. > > I want to still believe you, so I will do so. Please feel free to keep > contributing to DAMON as long as that's what you want to do. But, please aware > of the fact that DAMON maintainer has poor volatile memory and working with > limited resource, and try to make every conversation super clear and > transparent, from next time. Thank you for your honesty, and for still trusting me. I will continue contributing to DAMON. I will work hard to make my emails clear and transparent, and I will ask questions whenever something is ambiguous, so we can stay aligned. > > [1] https://lore.kernel.org/20260318153731.97470-1-aethernet65535@gmail.com > [2] https://lore.kernel.org/20260327062627.66426-1-aethernet65535@gmail.com > [3] https://lore.kernel.org/20260330164347.12772-1-aethernet65535@gmail.com > [4] https://lore.kernel.org/20260402140314.74600-1-sj@kernel.org > [5] https://lore.kernel.org/20260402152915.75294-1-sj@kernel.org > [6] https://lore.kernel.org/20260403052837.58063-1-aethernet65535@gmail.com [1] https://lore.kernel.org/20260321002642.22712-1-aethernet65535@gmail.com [2] https://lore.kernel.org/20260325025317.86571-1-sj@kernel.org [3] https://lore.kernel.org/20260327062627.66426-1-aethernet65535@gmail.com [4] https://lore.kernel.org/20260403161906.65008-1-sj@kernel.org Best regards, Rui Yan