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AJvYcCUBcQDt5KH76llLiCfdzmDldreqFQSTEB6ni5VqALhN4wb9XH2fqQY00Pvfr5ny72CNUXIgKS0/YA==@kvack.org X-Gm-Message-State: AOJu0Yy0ikoYbI2L+lMQ42jOxtTExvdhCXaa+33031BLHjLHpcak2aqp AV9swF7z+bWt8Bzt8nzObV36f6znpdMBhhVXG+tys5ymIs+kcnSalzoixlszn88a/+HeSfZNIp3 hpsjWSXKTpPoB9jRL58PzjB7tmR6VND8= X-Gm-Gg: ASbGncs8t20uQZfM0pwydNM3qkMRUk+pdV9rfM4lfS6DC4LNNCUxIvMCHLfM7ctR16U 22Yyujhg2YgmlLEawCwGQtsT4ucZFuWgMJkQ5SST6rXUbdE76hl5ZzCd4MyyIAQ9zpv+DLF3GRr TdGcZBvCgSJqteBsu3ONlQpL37ovS/WbwjDTMJImO74y6eBdJrJBUSgPyKkpDIDQhcAdKEikrUF O8V/S2rgjqEBHS9inhXvqNBfncw2dg4WmenbimtM4JpVjKLqtDf3dSX93W+8GzndQpQBEDQT6g= X-Google-Smtp-Source: AGHT+IEbTF1Padja2a5VYTPxu9e01sfQgU7xUDhedDQcSi45ZcqbFc2By50SOlGmeATDd+z0rHt0ZHSn8owfVsEk02s= X-Received: by 2002:a5d:588b:0:b0:425:7f10:ada7 with SMTP id ffacd0b85a97d-42667458124mr907732f8f.20.1759896636654; Tue, 07 Oct 2025 21:10:36 -0700 (PDT) MIME-Version: 1.0 References: <20250930055826.9810-1-laoar.shao@gmail.com> <20250930055826.9810-4-laoar.shao@gmail.com> In-Reply-To: From: Alexei Starovoitov Date: Tue, 7 Oct 2025 21:10:25 -0700 X-Gm-Features: AS18NWAHpHX-o2MgG3uRPCIrdO8_WsGJ2z7_dnabrBdSIRdjp2sl6QIslommR8o Message-ID: Subject: Re: [PATCH v9 mm-new 03/11] mm: thp: add support for BPF based THP order selection To: Yafang Shao Cc: Andrew Morton , David Hildenbrand , ziy@nvidia.com, baolin.wang@linux.alibaba.com, Lorenzo Stoakes , Liam Howlett , npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, Johannes Weiner , usamaarif642@gmail.com, gutierrez.asier@huawei-partners.com, Matthew Wilcox , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Amery Hung , David Rientjes , Jonathan Corbet , 21cnbao@gmail.com, Shakeel Butt , Tejun Heo , lance.yang@linux.dev, Randy Dunlap , bpf , linux-mm , "open list:DOCUMENTATION" , LKML Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 3E36B140006 X-Rspamd-Server: rspam11 X-Rspam-User: X-Stat-Signature: uyqth6qdushu3ucdjf5uy681766f7mfi X-HE-Tag: 1759896637-889598 X-HE-Meta: U2FsdGVkX18atnJqJuYvnpAV37b1IiG4KgpGyAPeON2ZauWPp0ApEMK91y9y4UBNwmcGJORoeAddzJ2pMcwHWvSrudz66p9mtAKAn4IlZy8k6zeJvPbI/84ETgl5uVx/sdyhurlBRpWO5Hzyb+daZjQPYQv0rlEC/9/iOP9P62UbSei0gQhFI+thKW0lnuuc25B8bOcSgNDVSa5nH8uoBC75+IQmyWsypLTZRLPjrCCzZXRKAFeQ7y2O9zfg6USx45d6Edb5J5C1YVVCkxn6OZ6pTz7f0Yn9w4xAKNUPk/CNtqWj21Sn6g30d1FB5FxEYBiEkesS6vc10KFJ4cWdsHs1AcFIZyi35eZGYU82bGeBv42Sesq7Ndb1ATMCzMFufpwAD6suUHLhXLRnQGWfncAqnzSqmFE9bGdnGO0mj66K8FgXDSM94ecVZ8ra3QxSfF13SVByoxFLUr8sUEf3my4vUbk5WnacCMuTCx7//vCeLGpLOibNVYyfTI1vFA2icHF+vOJ+kNnAWfyaLpA3uOjebmxpNMCG5Ys0erz8cMHxo6AwRUQKho6GbJjIGHd2oJbeZUJg+Dt97FVvY02WSFX6PF9cOaPjP44/3FbWOLVmrojxYlhS9C8Ci8nfO8IDuEKtlGplYG0H8iz53LkStBrH0z26K7uxhsJ2//TgE5eVRt+khSb8qImZfJARgtxCQ7fULvu0VfRiwjECqLPI52yBKV0E4VrJ4mEjoZIv+NRpUa59UlFUk+eLHU9Kf9e3MveS2biXGa7xQlhLECcZ0qAs+MqeumY1cXb1IKgMk6nvd0ch/lqHR25fEzk9/wPrMPX6kZchv9aVXYHbsHDNSZotscsyWb7eTGdIPX0KEFuNNeRkTzc5qxoubIvEzkldhaSO20r6WHniRHCe55r4AYnLB+Yxx0rO/FcaDWylpHLnc2CMFdpgaHxAsQRn7KBjNuxDju+pVVT4t3pv1px pUU8Qwg7 NrvM+xtZFm5Q9PcDwg+tJmZ+MswdLZ/Jrh1jZlI960bSFMLBUvhIosqrDC3Dc67j9J2AdclHlodgAWFNiBKLMowFndMgg0R2pkZh54EL80YhCgIfz3YhfmkwsatXNIkbVTXpuN0J8WiONjBg2s3x+JLNhbNRaZFtH03pgY+7Pj4kTblKnGH5UrjKWdBnvyywVbmy/V3sKex2hB+T38947JGT4vsASNuw4T3iR/iHseN5nRsHaX8ADFa3/FxWxq3DH6FBtlduFQsv5w/esZIjS/JVnbka4Ji8ABGgEz767klItKGOVqRYcAT7KiLrCcClUlirKpDXDlD2FWLeSY/xDSSj8WJIUu2/oHSz3g/HbFGnlYZVZ1m9i7z1/faRTyij5AQkJkehvgSXBHo5TD3yMRZ0JY5bDEWWgUVTLFwwUNrWu4ipu7/MAJ5aofNTkxLj4m0b2uz008JDPiA6q8IEpFzPDgQ== 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, Oct 7, 2025 at 8:51=E2=80=AFPM Yafang Shao w= rote: > > On Wed, Oct 8, 2025 at 11:25=E2=80=AFAM Alexei Starovoitov > wrote: > > > > On Tue, Oct 7, 2025 at 1:47=E2=80=AFAM Yafang Shao wrote: > > > has shown that multiple attachments often introduce conflicts. This i= s > > > precisely why system administrators prefer to manage BPF programs wit= h > > > a single manager=E2=80=94to avoid undefined behaviors from competing = programs. > > > > I don't believe this a single bit. > > You should spend some time seeing how users are actually applying BPF > in practice. Some information for you : > > https://github.com/bpfman/bpfman > https://github.com/DataDog/ebpf-manager > https://github.com/ccfos/huatuo By seeing the above you learned the wrong lesson. These orchestrators and many others were created because we made mistakes in the kernel by not scoping the progs enough. XDP is a prime example. It allows one program per netdev. This was a massive mistake which we're still trying to fix. > > hid-bpf initially went with fmod_ret approach, deleted the whole thing > > and redesigned it with _scoped_ struct-ops. > > I see little value in embedding a bpf_thp_struct_ops into the > task_struct. The benefits don't appear to justify the added > complexity. huh? where did I say that struct-ops should be embedded in task_struct ?