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AJvYcCWUAaHDMkI7NelmWabqKxu1ifkdLvZBbbvwnz/Tlxr2X/naN9b08v116HMsakeAvb7lPKXiHwA+eQ==@kvack.org X-Gm-Message-State: AOJu0YxWO76R1D5p9Vw7/pNkBKmFfItNGidGQN623hA4ZtMUK+ws49up faQk1s+K9yH8Ukno8KuFCBLitX825ND+v8GdHxekCwOr2ej6OBh62tM1hVp1gxYoyGLIZlms6y9 Q38UsqngIGJUjcbppEIFWIvbssW5cpaSjxvJVqNO4JZY31+7pbBMZCwYO6gNMx0nWxW2FpMhyCf IeiXB11HDfcUDgwtVK5S/tt5A= X-Gm-Gg: ASbGncsddEcBKDWWV/AG5UPKyvqbUfDdoGEPi8mUeU9VILrMp2Ns4hiGrv1rah9ZrGi yEe8Joxj5MU2CFdNV/MAqQcH0mLzK4aY6GFW1FPDSri/b0XlhJEWjJ7Gjf35agll31WphRV6baW Q= X-Received: by 2002:a05:6902:120d:b0:e5d:f878:7b50 with SMTP id 3f1490d57ef6-e5df8787c7emr2021296276.23.1739820316797; Mon, 17 Feb 2025 11:25:16 -0800 (PST) X-Google-Smtp-Source: AGHT+IH7Qe5QzycrNb9QKTC0wgZIxUHrerzUiu11f7E3qUQAW/QjwcTNFBX+3lLbhYw3w99GE9kvpp8qxN+GpNe1iSw= X-Received: by 2002:a05:6902:120d:b0:e5d:f878:7b50 with SMTP id 3f1490d57ef6-e5df8787c7emr2021235276.23.1739820316328; Mon, 17 Feb 2025 11:25:16 -0800 (PST) MIME-Version: 1.0 References: <20250211004054.222931-1-npache@redhat.com> <20250211004054.222931-2-npache@redhat.com> In-Reply-To: From: Nico Pache Date: Mon, 17 Feb 2025 12:24:50 -0700 X-Gm-Features: AWEUYZlXTbDyGUTQq_7TpVE0pYdfK9lEJauhIky2UmMOE2WpxTluduTbJgChv78 Message-ID: Subject: Re: [RFC v2 1/5] mm: defer THP insertion to khugepaged To: Usama Arif Cc: linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, ryan.roberts@arm.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, cl@gentwo.org, vbabka@suse.cz, mhocko@suse.com, apopple@nvidia.com, dave.hansen@linux.intel.com, will@kernel.org, baohua@kernel.org, jack@suse.cz, srivatsa@csail.mit.edu, haowenchao22@gmail.com, hughd@google.com, aneesh.kumar@kernel.org, yang@os.amperecomputing.com, peterx@redhat.com, ioworker0@gmail.com, wangkefeng.wang@huawei.com, ziy@nvidia.com, jglisse@google.com, surenb@google.com, vishal.moola@gmail.com, zokeefe@google.com, zhengqi.arch@bytedance.com, jhubbard@nvidia.com, 21cnbao@gmail.com, willy@infradead.org, kirill.shutemov@linux.intel.com, david@redhat.com, aarcange@redhat.com, raquini@redhat.com, dev.jain@arm.com, sunnanyong@huawei.com, audra@redhat.com, akpm@linux-foundation.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, tiwai@suse.de, baolin.wang@linux.alibaba.com, corbet@lwn.net, shuah@kernel.org X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: DWkCjJA2zRqrodrodxJvcAn8isnQO1o9z2Ap4S48gIg_1739820317 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 06F7B80004 X-Stat-Signature: eb9anc99ad3m8pcqkthkbn3mm5zyu89z X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1739820318-82140 X-HE-Meta: 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 oz8K5ooW QqdIQ1YySeox3ohACYowgYjCmVGs2snyq3Rge9+L2AEMUi4XpUO2OP3YAQSSiWFHD8Q6cI/SSF5o60dJUD1Xf2Dy1wuJu2JVxKVHxjXzUXBgbiq4z9ZtCkt1X6eQjZVqisHQU3sHNYL9dzkk8lN0CEClrreX2y6vK78tTSZOhm/6PsVe2FUcf0dEd97SWLx2IM+GY/K9+OTpR7BXJstlazjWEMJr7bB418JvN2Va31FDrYG4elBNWrdqwnYC/symhIvAIFCs7551uyjKUfUOkX6GOffyJUsNxI/8oFiQvipOiQtA6wzBNrMB+CMN69Uaux6z+WQTqiXY7ur+y+oz2lmVN0xiKLhrwPKDfxIISDvZotKQ= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000503, 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 Mon, Feb 17, 2025 at 7:59=E2=80=AFAM Usama Arif = wrote: > > > > On 11/02/2025 00:40, Nico Pache wrote: > > setting /transparent_hugepages/enabled=3Dalways allows applications > > to benefit from THPs without having to madvise. However, the pf handler > > takes very few considerations to decide weather or not to actually use = a > > THP. This can lead to a lot of wasted memory. khugepaged only operates > > on memory that was either allocated with enabled=3Dalways or MADV_HUGEP= AGE. > > > > Introduce the ability to set enabled=3Ddefer, which will prevent THPs f= rom > > being allocated by the page fault handler unless madvise is set, > > leaving it up to khugepaged to decide which allocations will collapse t= o a > > THP. This should allow applications to benefits from THPs, while curbin= g > > some of the memory waste. > > > > Signed-off-by: Nico Pache > > --- > > include/linux/huge_mm.h | 15 +++++++++++++-- > > mm/huge_memory.c | 31 +++++++++++++++++++++++++++---- > > 2 files changed, 40 insertions(+), 6 deletions(-) > > > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > > index 93e509b6c00e..fb381ca720ea 100644 > > --- a/include/linux/huge_mm.h > > +++ b/include/linux/huge_mm.h > > @@ -44,6 +44,7 @@ enum transparent_hugepage_flag { > > TRANSPARENT_HUGEPAGE_UNSUPPORTED, > > TRANSPARENT_HUGEPAGE_FLAG, > > TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, > > + TRANSPARENT_HUGEPAGE_DEFER_PF_INST_FLAG, > > No strong preference, but maybe just TRANSPARENT_HUGEPAGE_DEFER_FLAG migh= t be better? Not a bad idea, TRANSPARENT_HUGEPAGE_DEFER_PF_INST_FLAG is pretty long! >