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[79.242.59.51]) by smtp.gmail.com with ESMTPSA id 125sm11520392wmb.12.2021.07.26.00.11.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 26 Jul 2021 00:11:38 -0700 (PDT) To: "Alejandro Colomar (man-pages)" , Pankaj Gupta Cc: linux-man@vger.kernel.org, Michael Kerrisk , Andrew Morton , Michal Hocko , Oscar Salvador , Jann Horn , Mike Rapoport , Linux API , Linux MM References: <20210712083917.16361-1-david@redhat.com> <51ec094e-e402-d8a4-d65f-24b8d7929707@gmail.com> From: David Hildenbrand Organization: Red Hat Subject: Re: [PATCH v1] madvise.2: Document MADV_POPULATE_READ and MADV_POPULATE_WRITE Message-ID: <6c7543e4-23c8-8f2d-dc89-480be13738b3@redhat.com> Date: Mon, 26 Jul 2021 09:11:37 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 MIME-Version: 1.0 In-Reply-To: <51ec094e-e402-d8a4-d65f-24b8d7929707@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org Hi Alex, >>> --- >>> man2/madvise.2 | 80 ++++++++++++++++++++++++++++++++++++++++++++++++++ >>> 1 file changed, 80 insertions(+) >>> >>> diff --git a/man2/madvise.2 b/man2/madvise.2 >>> index f1f384c0c..3ec8c53a7 100644 >>> --- a/man2/madvise.2 >>> +++ b/man2/madvise.2 >>> @@ -469,6 +469,59 @@ If a page is file-backed and dirty, it will be written back to the backing >>> storage. >>> The advice might be ignored for some pages in the range when it is not >>> applicable. >>> +.TP >>> +.BR MADV_POPULATE_READ " (since Linux 5.14) > > s/$/"/ Thanks! > >>> +Populate (prefault) page tables readable for the whole range without actually > > See the following extract from man-pages(7): > > $ man 7 man-pages | sed -n '/Use semantic newlines/,/^$/p'; > Use semantic newlines > In the source of a manual page, new sentences should be > started on new lines, and long sentences should split into > lines at clause breaks (commas, semicolons, colons, and so > on). This convention, sometimes known as "semantic new‐ > lines", makes it easier to see the effect of patches, which > often operate at the level of individual sentences or sen‐ > tence clauses. Thanks, something like the following (also limiting to 80 characters per page) work? " Populate (prefault) page tables readable for the whole range without actually reading. Depending on the underlying mapping, map the shared zeropage, preallocate memory or read the underlying file; files with holes might or might not preallocate blocks. " > >>> +reading. Depending on the underlying mapping, map the shared zeropage, >>> +preallocate memory or read the underlying file; files with holes might or >>> +might not preallocate blocks. >>> +Do not generate >>> +.B SIGBUS >>> +when populating fails, return an error instead. >>> +.IP >>> +If >>> +.B MADV_POPULATE_READ >>> +succeeds, all page tables have been populated (prefaulted) readable once. >>> +If >>> +.B MADV_POPULATE_READ >>> +fails, some page tables might have been populated. >>> +.IP >>> +.B MADV_POPULATE_READ >>> +cannot be applied to mappings without read permissions >>> +and special mappings marked with the kernel-internal >>> +.B VM_PFNMAP >>> +and >>> +.BR VM_IO . >>> +.IP >>> +Note that with >>> +.BR MADV_POPULATE_READ , >>> +the process can be killed at any moment when the system runs out of memory. >>> +.TP >>> +.BR MADV_POPULATE_WRITE " (since Linux 5.14) > > s/$/"/ Thanks! -- Thanks, David / dhildenb