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Thu, 09 Jul 2026 08:39:33 -0700 (PDT) From: Xueyuan Chen To: hannes@cmpxchg.org Cc: xueyuan.chen21@gmail.com, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, baohua@kernel.org, zhaonanzhe@xiaomi.com, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, chrisl@kernel.org, kasong@tencent.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, youngjun.park@lge.com, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, qi.zheng@linux.dev, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com Subject: Re: [RFC PATCH v2 2/3] mm: distinguish large folio swap allocation failures Date: Thu, 9 Jul 2026 23:39:24 +0800 Message-ID: <20260709153924.772408-1-xueyuan.chen21@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 80F4640011 X-Stat-Signature: qmhr954t4751eindx4x3rcp4zumptimq X-HE-Tag: 1783611575-623904 X-HE-Meta: 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 jeZuhyn1 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jul 09, 2026 at 11:04:23AM -0400, Johannes Weiner wrote: Hi Johannes, >On Thu, Jul 09, 2026 at 11:01:12AM -0400, Johannes Weiner wrote: >> On Thu, Jul 09, 2026 at 10:51:23PM +0800, Xueyuan Chen wrote: >> > @@ -5550,10 +5558,7 @@ long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) >> > >> > if (mem_cgroup_disabled() || do_memsw_account()) >> > return nr_swap_pages; >> > - for (; !mem_cgroup_is_root(memcg); memcg = parent_mem_cgroup(memcg)) >> > - nr_swap_pages = min_t(long, nr_swap_pages, >> > - READ_ONCE(memcg->swap.max) - >> > - page_counter_read(&memcg->swap)); >> > + nr_swap_pages = min(nr_swap_pages, page_counter_margin(&memcg->swap)); >> >> This hunk is unrelated to this patch. Don't mix refactor work with new >> functionality. Make the previous patch a pure refactor job (where you >> add page_counter_margin() and use it here ^), like I had proposed. You're right, that refactor doesn't belong in patch 2. >I also liked my version of mem_cgroup_get_nr_swap_pages() a bit >better. Please just use my patch, keep the From: and you can add > >Signed-off-by: Johannes Weiner > I'll use your version in v3, keep your From: and Signed-off-by, and make patch 1 a pure refactor patch that adds page_counter_margin() and converts mem_cgroup_get_nr_swap_pages() to use it. Patch 2 will only keep the functional folio_alloc_swap()/memcg charge changes. Thanks, Xueyuan