[PATCH] D115957: [Support] Revert posix_fallocate in resize_file

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
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This reverts 3816c53f040cc6aa06425978dd504b0bd5b7899c and removes follow-up
fixups.

The original intention was to show error earlier (posix_fllocate time) than
later for ld.lld but it appears to cause some problems which make it not free.

- FreeBSD ZFS: EINVAL, not too bad.
- NetBSD: maybe EOPNOTSUPP
- Linux tmpfs: unless and tmpfs is set up to use huge pages (requires CONFIG_TRANSPARENT_HUGE_PAGECACHE=y), I can consistently demonstrate ~300ms delay for a 1.4GiB output.
- Linux ext4: I currently don't measure any benefit
- The current code organization of `defined(HAVE_POSIX_FALLOCATE)` costs us a macro dispatch for AIX.

I think we should just remove it. I think if it ever finds demonstrable benefit,
it is likely Linux specific and will not need HAVE_POSIX_FALLOCATE.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D115957

Files:
  llvm/cmake/config-ix.cmake
  llvm/include/llvm/Config/config.h.cmake
  llvm/lib/Support/Unix/Path.inc
  llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
  utils/bazel/llvm-project-overlay/llvm/config.bzl
  utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h
  utils/bazel/llvm_configs/config.h.cmake

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