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b=HetAil9r8Am1raizRyvhUG/lw4wfYEoQA/9APIZG3YginIabgQH0C8ANZXjw2Y2Z3 jBVjrKFMwSrWTLn5+kyKOecmhQiS5HLDw1e7N7aJ6y6K+KXuxtm9rfcb+RUqi5qZYK J+TU5//SgG++UfdgVeSTAcfsZQ7CHLh8fkX5jswzbSmylMVy55rY9f9ocr+c7NSVh0 0D+XfW7JgkTo+N15+rIdFFNFFIa3FAivl41puNP0wvNdnAyEIq+k/UKVowd11bihWw LLQTad7/nsLlcwHxghws/cLDX45lAIIpJZaRky5TGeuv/8NZZN2XaK6cSVsLHVNR3A wBilBn7I31hAA== From: SeongJae Park To: SeongJae Park Cc: Honggyu Kim , akpm@linux-foundation.org, apopple@nvidia.com, baolin.wang@linux.alibaba.com, damon@lists.linux.dev, dave.jiang@intel.com, hyeongtak.ji@sk.com, kernel_team@skhynix.com, linmiaohe@huawei.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, lizhijian@cn.fujitsu.com, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, rakie.kim@sk.com, rostedt@goodmis.org, surenb@google.com, yangx.jy@fujitsu.com, ying.huang@intel.com, ziy@nvidia.com Subject: Re: [RFC PATCH 0/4] DAMON based 2-tier memory management for CXL memory Date: Wed, 17 Jan 2024 13:24:18 -0800 Message-Id: <20240117212419.51845-1-sj@kernel.org> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240117211103.51806-1-sj@kernel.org> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Stat-Signature: 7mjn54uurafru6w7gch8kh3y7k1xmw5g X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 0891240023 X-HE-Tag: 1705526662-826801 X-HE-Meta: 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 cXqC/Lfw SRKvuIQvHa9l+/uJ547V+gwOtpEnNHejJQwvu3fUpXehmm3Uy3ka+k4HKeQ4vPCRSMMxGhiD5I5eKsY63EHLD6OFpVg06L5rwNK54zaqXu5G6MJQdxDBsZ62oZBha9CrvlUrKX+hvaMLewPcXxPJDUlPR5S/qs+2RkzwOM3JoKJAi1F97XPEoEBzaf4wcbL5vjCl/FkuUtGHlLXfwqnyw3vQMlgruUkOTekUZuOZZtteg5FwEbTAprXni4O84mhHFmD1wfFv8qv8p4+wswuxZgYkeN4eMMvhW3cuiwGRkZByWJd4= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, 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 Wed, 17 Jan 2024 13:11:03 -0800 SeongJae Park wrote: [...] > Hi Honggyu, > > On Wed, 17 Jan 2024 20:49:25 +0900 Honggyu Kim wrote: > > > Hi SeongJae, > > > > Thanks very much for your comments in details. > > > > On Tue, 16 Jan 2024 12:31:59 -0800 SeongJae Park wrote: > > [...] > > > To this end, I feel the problem might be able te be simpler, because this > > > patchset is trying to provide two sophisticated operations, while I think a > > > simpler approach might be possible. My humble simpler idea is adding a DAMOS > > > operation for moving pages to a given node (like sys_move_phy_pages RFC[1]), > > > instead of the promote/demote. Because the general pages migration can handle > > > multiple cases including the promote/demote in my humble assumption. [...] > > > In more detail, users could decide which is the appropriate node for promotion > > > or demotion and use the new DAMOS action to do promotion and demotion. Users > > > would requested to decide which node is the proper promotion/demotion target > > > nodes, but that decision wouldn't be that hard in my opinion. > > > > > > For this, 'struct damos' would need to be updated for such argument-dependent > > > actions, like 'struct damos_filter' is haing a union. > > > > That might be a better solution. I will think about it. > > More specifically, I think receiving an address range as the argument might > more flexible than just NUMA node. Maybe we can imagine proactively migrating > cold movable pages from normal zones to movable zones, to avoid normal zone > memory pressure. Yet another crazy idea. Finding hot regions in the middle of cold region and move to besides of other hot pages. As a result, memory is sorted by access temperature even in same node, and the system gains more spatial locality, which benefits general locality-based algorithms including DAMON's adaptive regions adjustment. Thanks, SJ [...]