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AJvYcCUCanA5qHzKWq3/f0NZRgx6x/tKUdPWpPmQjHdzk3jgaxYNvm6vqM2sLOB21yeyk+7F4yjQrO8uFDAgzb0gbJb+gIE= X-Gm-Message-State: AOJu0YzTSUXetfUV9HTrpT0aLboufEmu93hEcBOVsk1e4lj3qKLT1LY8 7l+eIhFNvoDGTu8rkjoTrycHfjP6JgahYPdRyZMJ5Cdx4jwlFS/zUEKAOtrSVneaS/IOqWvqQ6B UzPFaeev9QxzPpVN9B80y35XDRtQ= X-Google-Smtp-Source: AGHT+IGkOVmVNmOWwBaHCXLri82Ny30fL/zbqbahI9+MDgOiz1A3svsaJXsUNkAM7XRnziT3OAWkPmiXZDiRDy6UwKU= X-Received: by 2002:a05:6a20:65a2:b0:1bd:2d53:35d8 with SMTP id adf61e73a8af0-1bd2d539644mr5541216637.49.1719521435007; Thu, 27 Jun 2024 13:50:35 -0700 (PDT) MIME-Version: 1.0 References: <20240627170900.1672542-1-andrii@kernel.org> <20240627125938.da3541c6babfe046f955df7a@linux-foundation.org> In-Reply-To: <20240627125938.da3541c6babfe046f955df7a@linux-foundation.org> From: Andrii Nakryiko Date: Thu, 27 Jun 2024 13:50:22 -0700 Message-ID: Subject: Re: [PATCH v6 0/6] ioctl()-based API to query VMAs from /proc//maps To: Andrew Morton Cc: Andrii Nakryiko , linux-fsdevel@vger.kernel.org, brauner@kernel.org, viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, gregkh@linuxfoundation.org, linux-mm@kvack.org, liam.howlett@oracle.com, surenb@google.com, rppt@kernel.org, adobriyan@gmail.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 37AB118000F X-Stat-Signature: e5p7ziagem83m3ihb9746e6z8g8krn7f X-HE-Tag: 1719521436-541131 X-HE-Meta: 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 /h7U8liw x4f1dVvIm7eFmd6Vjc3QFv0b1IlIW6fi2PSPV8OvrxPOE/6xQ/bCjWz7gEawl3qRC9QUVhRMB5PSSrEhkQYaf4pXCxsfSgyvNwBhg4uSiPW3FNIc3AvZ2Q2UXMhW76flTmEIk9IH88KKYGRaJcTd2KdUcaWd2QasNDhAJvBeLGp+qKY4k6dOIYRWcAWfo1/uaAeFEapHlgNHWzfUZdQQoier+vaH+ZqrGEZl8AvEKYoo8Jnt2sYV37U0fLOKsEaATrm4Swt9fkjn9HFUu/eLG6QjJOpxGR6rFNyfQvcDgQNfvF3AexDbZAJBlto5IncbrfeeNZqSmGVqqeq91cfBaTIPYhvuY5j6qLyMMRmDuh1lrcsoiO4UB6K+wyv518Hdl3E7aapqBYtgvWzLPOipoRIvpP+dj10103+i02TFJsHxTJxvu0BuveHuRHRLvvcY3WgKU X-Bogosity: Ham, tests=bogofilter, spamicity=0.002020, 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 Thu, Jun 27, 2024 at 12:59=E2=80=AFPM Andrew Morton wrote: > > On Thu, 27 Jun 2024 10:08:52 -0700 Andrii Nakryiko wr= ote: > > > Implement binary ioctl()-based interface to /proc//maps file to al= low > > applications to query VMA information more efficiently than reading *al= l* VMAs > > nonselectively through text-based interface of /proc//maps file. > > I appreciate the usefulness for monitoring large fleets, so I'll add > this version to mm-unstable. As we're almost at -rc6 I'll await > further review before deciding on the next steps. > > Is it possible/sensible to make this feature Kconfigurable so that people= who > don't need it can omit it? It's just a matter of #ifdef/#endif, so not hard, technically speaking. But I'm wondering what's the concern? This is mostly newly added code (except factoring out get_vma_name logic, which won't be #ifdef'ed anyways), so if no one is using this new API, then it should cause no issue. Generally speaking, I'd say if we don't *have to* add the Kconfig option, I'd prefer that. But if you feel strongly, it's not hard for me to do, of course. Or are you concerned with the vmlinux code size increase? It doesn't seem to be large enough to warrant a Kconfig, IMO (from bloat-o-meter): do_procmap_query - 1308 +1308 get_vma_name - 283 +283 procfs_procmap_ioctl - 47 +47 show_map_vma 444 274 -170 But again, do let me know if you insist.