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Tue, 16 Jun 2026 06:47:10 -0700 (PDT) Date: Tue, 16 Jun 2026 09:47:07 -0400 From: Gregory Price To: Brendan Jackman Cc: "Vlastimil Babka (SUSE)" , "David Hildenbrand (Arm)" , Balbir Singh , lsf-pc@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, damon@lists.linux.dev, kernel-team@meta.com, gregkh@linuxfoundation.org, rafael@kernel.org, dakr@kernel.org, dave@stgolabs.net, jonathan.cameron@huawei.com, dave.jiang@intel.com, alison.schofield@intel.com, vishal.l.verma@intel.com, ira.weiny@intel.com, dan.j.williams@intel.com, longman@redhat.com, akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, osalvador@suse.de, ziy@nvidia.com, matthew.brost@intel.com, joshua.hahnjy@gmail.com, rakie.kim@sk.com, byungchul@sk.com, ying.huang@linux.alibaba.com, apopple@nvidia.com, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, yury.norov@gmail.com, linux@rasmusvillemoes.dk, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, tj@kernel.org, hannes@cmpxchg.org, mkoutny@suse.com, jackmanb@google.com, sj@kernel.org, baolin.wang@linux.alibaba.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, muchun.song@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, jannh@google.com, linmiaohe@huawei.com, nao.horiguchi@gmail.com, pfalcato@suse.de, rientjes@google.com, shakeel.butt@linux.dev, riel@surriel.com, harry.yoo@oracle.com, cl@gentwo.org, roman.gushchin@linux.dev, chrisl@kernel.org, kasong@tencent.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, zhengqi.arch@bytedance.com, terry.bowman@amd.com, Matthew Wilcox Subject: Re: [Lsf-pc] [LSF/MM/BPF TOPIC][RFC PATCH v4 00/27] Private Memory Nodes (w/ Compressed RAM) Message-ID: References: <9f1815b0-896b-44ab-9e6d-9316d8f11033@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Jun 16, 2026 at 11:57:42AM +0000, Brendan Jackman wrote: > On Mon Jun 15, 2026 at 2:38 PM UTC, Vlastimil Babka (SUSE) wrote: > > On 6/12/26 17:29, Gregory Price wrote: > >> On Wed, Jun 10, 2026 at 04:12:52PM -0400, Gregory Price wrote: > >>> On Wed, Jun 10, 2026 at 08:59:59PM +0200, David Hildenbrand (Arm) wrote: > >>> > > > > > > I think the memalloc approach is dangerous due to unexpected nesting. There > > might be nested page allocations in page allocation itself (due to some > > debugging option). But also interrupts do not change what "current" points > > to. Suddenly those could start requesting folios and/or private nodes and be > > surprised, I'm afraid. > > Minor side-note: couldn't we just define it such that the allocator > ignores the context when not in_task() (and warn if you try to enter the > context while not currently in_task())? > > (Don't think this would change the conclusion very much, e.g. doesn't > help with the nesting issues. Mostly curious in case I'm missing a > detail here). > I looked at this - only solves one issue and oh boy is that an obtuse confusing condition to understand. We still suffer from recursion in reclaim. ~Gregory