io: use posix_fadvise() instead of readahead() #404
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@swift-ci please test |
readahead() is a Linux-specific system call, and many C libraries (e.g. Android's Bionic) do not declare it by default. A more-portable alternative is to use posix_fadvise() with `POSIX_FADV_WILLNEED`. This is functionally equivalent to readahead() on Linux. Additionally, on FreeBSD, Dispatch is currently using fcntl() with `F_RDAHEAD`. This is not exactly equivalent to Darwin's `F_RDADVISE`. Using posix_fadvise() should work better here too.
MadCoder
approved these changes
Oct 17, 2018
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@swift-ci please test |
1 similar comment
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@swift-ci please test |
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@MadCoder - okay to merge? |
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@ktopley-apple - okay to merge this as well? |
rokhinip
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Nov 5, 2021
io: use posix_fadvise() instead of readahead() Signed-off-by: Kim Topley <ktopley@apple.com>
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readahead() is a Linux-specific system call, and many C libraries (e.g.
Android's Bionic) do not declare it by default. A more-portable alternative is
to use posix_fadvise() with
POSIX_FADV_WILLNEED. This is functionallyequivalent to readahead() on Linux.
Additionally, on FreeBSD, Dispatch is currently using fcntl() with
F_RDAHEAD.This is not exactly equivalent to Darwin's
F_RDADVISE. Using posix_fadvise()should work better here too.