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See http://www.infradead.org/rpr.html X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 088E94002C X-Stat-Signature: p6cd43ijmn8k6z1uqxebjs91g9sfn7pb X-Rspam-User: X-HE-Tag: 1675873214-791608 X-HE-Meta: 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 V7TAONCs 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 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: On Wed, Feb 08, 2023 at 04:09:51PM +0000, David Howells wrote: > How about one of two different solutions? > > (1) Repurpose the function I proposed for generic_file_splice_read() but only > for splicing from O_DIRECT files; reading from non-O_DIRECT files would > use an ITER_PIPE as upstream. Given the amounts of problems we had with O_DIRECT vs splice, and the fact that even doing this is a bit pointless that seems sensible to me. > for splicing from O_DIRECT files, as (1), but also replace the splice > from a buffered file with something like the patch below. This uses > filemap_get_pages() to do the reading and to get a bunch of folios from > the pagecache that we can then splice into the pipe directly. I defintively like the idea of killing ITER_PIPE. Isn't the 16 folios in a folio tree often much less than what we could fit into a single pipe buf? Unless you have a file system that can use huge folios for buffered I/O and actually does this might significantly limit performance. With that in mind I'll try to find some time to review your actual patch, but I'm a little busy at the moment.