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AJvYcCUrCCMoIqZGTwSZ95nJsOzYIdZqg40326ILsFDp6xt3MtsI3Yz0B/N3Vop+Lu+xtcyZidgXHCF3qaYZrqaJmRzdiQI= X-Gm-Message-State: AOJu0Yy7dGsrEVjVtFhmQi0ww8Ifjulp/J1CthLxBw9UkTUQKGvT+nbj 0FR8fWBVl5dx/0LebQyvNSus9JnI51VHxzqnu+TMAE2AP3WyIYQs/4aCRBMTGKk9jULMwYF0IOl hitgxgXaQ8ej6RBGem+ZjTTuavhQ= X-Google-Smtp-Source: AGHT+IHX7Wpx+GDA6dByQaJ3O5AT6e1sonZooDx+69THpMDnjEja2+Mz49EXejtB/GGkmGDL+Yu9WSjwaySafKdXJX0= X-Received: by 2002:a5d:6385:0:b0:33b:4ec0:8161 with SMTP id p5-20020a5d6385000000b0033b4ec08161mr3778611wru.10.1708102460458; Fri, 16 Feb 2024 08:54:20 -0800 (PST) MIME-Version: 1.0 References: <20240209040608.98927-1-alexei.starovoitov@gmail.com> <20240209040608.98927-5-alexei.starovoitov@gmail.com> In-Reply-To: From: Alexei Starovoitov Date: Fri, 16 Feb 2024 08:54:08 -0800 Message-ID: Subject: Re: [PATCH v2 bpf-next 04/20] mm: Expose vmap_pages_range() to the rest of the kernel. To: Christoph Hellwig Cc: Linus Torvalds , bpf , Daniel Borkmann , Andrii Nakryiko , Kumar Kartikeya Dwivedi , Eddy Z , Tejun Heo , Barret Rhoden , Johannes Weiner , Lorenzo Stoakes , Andrew Morton , Uladzislau Rezki , linux-mm , Kernel Team Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 390F510000D X-Rspam-User: X-Stat-Signature: hypbaid96xon6d5iqo866m1ftpz3awkg X-Rspamd-Server: rspam03 X-HE-Tag: 1708102462-694595 X-HE-Meta: U2FsdGVkX18RWgvYQmFW3C04qwL0Us7CIElb3AE595bJJpsIoAG/r0eyhH5McqWZQsQhldoLst10RqACUwF/u2dfK82UakF7A4Mnfzbf3bMxlScHnehNB2EHYnhbjf291Ud/GnaT0Cl7ZzG+lSNQAPxPTL8AqUmbQUBaUkQhhmBEvKu8WbThk54KFclWAEaEiTgb7Z6w5bGl6MnPgsp0GtEtorUb5A3BzoP26xZawzVBqmGysme/GM4da0RgGtaGHq2qi0JOfR2jVudbn5ZJOQRRUNBA/0Zfhh+SDSHPeiMDhTh5O1u7Z83r0jHf0pkSyhnKRp9x8rchTfwXxFX4yUEQEPFAOkYu2q4TpQK5ylmTmIIG4mnkjye71YT5fuQ6sPKsxDvWFNr1saFynE+S9S4ripQos2fVeIMQMV9exsMlWXm+jg6WV78gLSEJmYbeVCFFbbHgydzwJb1zHrbDg5RfuuB3gCERr88wEpDBjyDmcu7yq87Kq0NIjeXwRvhSP4Rj9r4O9mSDdTSqm9xVXz9nzN9wATU+qAoG+wh6A8sK9KiDOTVYMW247/IX6e680a6kD3uUFUrMYhhnwtyysQFwcPSBv5o+MsokdN5cEF046vrH7nNezNTyrL5GCOrr4jN5ESc+eVRXzE6I7VJfRnIiyCMewYBreNSVKwcmT0XrFqY/kfvSBXcbJgTMdZdOLFqzbchjQrIMcVoFC+bELPRm2qvSCX8G01jbU+e8QeIPnK/R9MyHVd+pptAuBS7vjCjNwlWlQzO8siX0ufZrNiFhUB10EuTdUVuJdrjrwQOz8eeBTH4SdN2XTpUmAvt/RFnlkdkVD0gOMnk89G+ZYclxxxMoL4saOX3y3W088OIoVpQSg6UFIf3YaRTWc7N58ky1pB1CUDIsoHMi+9rMtjxEfEcPNeqlPodcLHghnEbJdux6ox03wXVpT3znz8DOI034hioBqKnyfk2t72g Gevsvuat Tmztxg1iXrdTGPdmi90TcO9GTnVA6Soaklg2Ffnqd4zpgjt9j9GBdQn7i351YhuH0diGh628zVwgyoGxISJCBCP0WokAMPrp/iYtHGPpSb4ZU1oyzbP+PVhMLCFc4HXuQOxHW3OcBFy8xTZtFRFts2a+KZgcgw5JNomA9+RfNqeemTksZtBIacpU9ijbQtRFjIWFT0pQ3JEntqQ6v5tBga3U+AWrRth1b4I/xUn0493uCiHs1kPzKh/YtPv8U7GguDB78S8JHZ35xTTa65UIEnnfnhAhNrHslhOb0J9ZBnb4gax+2NIcOlmSOZyW/JeKhGDyWNLbSyXm8PxOy7iYlcCKO732nECROONOPuethzHRYl53LX4fZVATBNNr7DkHDj7o6AJ83UHkWCBD+2CLWVE0oF7gcAut9Wz2KojSEURv+e3HVGcDxMt90IOpH/XZHrDQ2g8x550qKyKK7dLRezAQ3p4TWmva0ALko0S8GwLx++qc= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000055, 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 Fri, Feb 16, 2024 at 1:31=E2=80=AFAM Christoph Hellwig wrote: > > On Thu, Feb 15, 2024 at 12:50:55PM -0800, Alexei Starovoitov wrote: > > So, since apply_to_page_range() is available to the kernel > > (xen, gpu, kasan, etc) then I see no reason why > > vmap_pages_range() shouldn't be available as well, since: > > In case it wasn't clear before: apply_to_page_range is a bad API to > be exported. We've been working on removing it but it stalled. > Exposing something that allows a module to change arbitrary page table > bits is not a good idea. I never said that that module should do that. > Please take a step back and think of how to expose a vmalloc like > allocation that grows only when used as a proper abstraction. I could > actually think of various other uses for it. "vmalloc like allocation that grows" is not what I'm after. I need 4G+guard region at the start. Please read my earlier email and reply to my questions and api proposals. Replying to half of the sentence, and out of context, is not a productive discussion.