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Tue, 10 Feb 2026 11:23:39 -0800 (PST) MIME-Version: 1.0 References: <20260208215839.87595-2-nphamcs@gmail.com> <20260208222652.328284-1-nphamcs@gmail.com> In-Reply-To: From: Nhat Pham Date: Tue, 10 Feb 2026 11:23:27 -0800 X-Gm-Features: AZwV_QhDHop3xuaKmlrjyEY_sdgVS3677YBZxGUueqqiU-9ugNQbef3e4wRWWfo Message-ID: Subject: Re: [PATCH v3 00/20] Virtual Swap Space To: Kairui Song Cc: linux-mm@kvack.org, akpm@linux-foundation.org, hannes@cmpxchg.org, hughd@google.com, yosry.ahmed@linux.dev, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, len.brown@intel.com, chengming.zhou@linux.dev, chrisl@kernel.org, huang.ying.caritas@gmail.com, ryan.roberts@arm.com, shikemeng@huaweicloud.com, viro@zeniv.linux.org.uk, baohua@kernel.org, bhe@redhat.com, osalvador@suse.de, christophe.leroy@csgroup.eu, pavel@kernel.org, kernel-team@meta.com, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-pm@vger.kernel.org, peterx@redhat.com, riel@surriel.com, joshua.hahnjy@gmail.com, npache@redhat.com, gourry@gourry.net, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, rafael@kernel.org, jannh@google.com, pfalcato@suse.de, zhengqi.arch@bytedance.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: CB83314000C X-Stat-Signature: io1qcdpfb7mt95by5m1iqyq4hj7fafa6 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1770751420-903156 X-HE-Meta: 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 GEC/s9ZI 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 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 Tue, Feb 10, 2026 at 11:11=E2=80=AFAM Nhat Pham wrot= e: >> > Hmm this one I don't think I can reproduce without your laptop ;) > > Jokes aside, I did try to run the kernel build with disk swapping, and > the performance is on par with baseline. Swap performance with NVME > swap tends to be dominated by IO work in my experiments. Do you think > I missed something here? Maybe it's the concurrency difference (since > I always run with -j$(nproc), i.e the number of workers =3D=3D the number > of processors). Ah I just noticed that your numbers include only systime. Ignore my IO comments then. (I still think in real production system, with disk swapping enabled, then IO wait time is going to be really important. If you're going to use disk swap, then this affects real time just as much if not more than kernel CPU overhead).