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b=tYWr05VqUGfZCU4UNdsPkbnCkKzql6AFkxRBrIge9Nay2wl9ZhP93gID2fwWkLoxu QC2yQTBVAinsMGdpwouXACSdaPKDDyTyo/HSYnjDe+3LRhj6w7mm8pkdnNEEmSwZLt c9bhJgetOIuabcEBRDd5gSpuYpFrgAbY/FvPCO773e4i+Z3MFnyoryEBUR5tZX3Vn5 Ng8Eo0NnZDYMcxKbnMx19DM1lHhie/UtN152LcesqeQ5KVRFwF2NxdKFw881V+n9q5 V2wzVRiE3vcehY5Wpvs4uQmgJ40wcuBPriuKAymjVGbg4ld1QvA6ymlDXqmwPXG2xT sTHXmU2/WEIMQ== From: SeongJae Park To: JaeJoon Jung Cc: SeongJae Park , damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rgbi3307@nate.com Subject: Re: [PATCH 1/2] mm/damon/core: modified and tunning damon_split_regions_of() Date: Thu, 15 Jan 2026 19:18:25 -0800 Message-ID: <20260116031826.72372-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 4450F40008 X-Rspam-User: X-Stat-Signature: igt9119zrrgjy3eitjz4jw5drna4ih4h X-HE-Tag: 1768533524-317648 X-HE-Meta: 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 uC0C0IUr khKKG X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 15 Jan 2026 05:18:51 +0900 JaeJoon Jung wrote: > On Thu, 15 Jan 2026 at 00:46, SeongJae Park wrote: > > > > Hello JaeJoon, thank you for continued interest in DAMON. > > > > On Tue, 13 Jan 2026 21:16:42 +0900 JaeJoon Jung wrote: > > > > > Before modification: > > > sz_region > > > |--------|--------|--------||--------|--------|--------|--------| > > > nr_subs: 1 2 3 4 5 9 > > > split random: <----------- (*] randmon LOST --------------> > > > > > > When dividing sz_region at rand, the random value may be small, such as > > > 1 or 2. At this time, there is a problem that only the front areas > > > corresponding to 1 and 2 are divided, and the remaining back area > > > becomes too wide. If the area is too wide, there will be many missed > > > address access judgments. > > > > > > After modification: > > > sz_region > > > |--------|--------|--------|--------|--------|--------|--------|| > > > nr_subs: 1 2 3 4 5 9 > > > split from <------------ (sz_region / nr_subs) ------------------> > > > > > > It is recommended to divide sz_region evenly in the ratio (sz_region / > > > nr_subs) rather than using rand. In this way, if you decide nr_subs well, > > > you can logically match the number of divisions and their sizes. > > > > I was thinking about how to reply to this patch. Since it is taking unusually > > long time, let me add short comments for direct future of this patch. > > After much thought, you ask a simple question below. > > > > > The existing code uses random() for a reason. This change might break it. Can > > you further explain what was the point of the use of random(), and why this > > change is not breaking it? > > To find a needle in a haystack, is it right to keep poking around randomly? > > > > > > > > > Signed-off-by: JaeJoon Jung > > > > Unless you can give me a convincing answer to my above question, > > > > Nacked-by: SeongJae Park > > > > Same for your followup patch [1]. Btw, please send patches of same series as > > one thread from next time. > > I sent you two after much deliberation so that you can see them clearly. Unfortunately what I asked are still not clearly answered to me. And based on our past conversations including the recent one that I acknowledged as a communication failure [1] and this thread, I expect asking you more questions will not work for me. I don't think that's someone's fault, but obviously that's the current situation. I will not ask you more questions for the reason, unless I get a reason to change my mind. So, to make it crystal clear, for this patch and the one you posted together, Nacked-by: SeongJae Park Thanks, SJ [1] https://lore.kernel.org/20260101224420.73826-1-sj@kernel.org [...]