[llvm] 98e0b2c - [Support] Revert posix_fallocate in resize_file
Fangrui Song via llvm-commits
llvm-commits at lists.llvm.org
Mon Dec 20 11:16:07 PST 2021
Author: Fangrui Song
Date: 2021-12-20T11:16:03-08:00
New Revision: 98e0b2cf700191558268728f2a8e65dfe13bf0da
URL: https://github.com/llvm/llvm-project/commit/98e0b2cf700191558268728f2a8e65dfe13bf0da
DIFF: https://github.com/llvm/llvm-project/commit/98e0b2cf700191558268728f2a8e65dfe13bf0da.diff
LOG: [Support] Revert posix_fallocate in resize_file
This reverts 3816c53f040cc6aa06425978dd504b0bd5b7899c and removes follow-up
fixups.
The original intention was to show error earlier (posix_fallocate time) than
later for ld.lld but it appears to cause some problems which make it not free.
* FreeBSD ZFS: EINVAL, not too bad.
* FreeBSD UFS: according to khng "devastatingly slow on freebsd because UFS on freebsd does not have preallocation support like illumos. It zero-fills."
* NetBSD: maybe EOPNOTSUPP
* Linux tmpfs: unless 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 don't measure any benefit, either backed by a hard disk or by a file in tmpfs.
* 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 posix_fallocate ever finds demonstrable benefit,
it is likely Linux specific and will not need HAVE_POSIX_FALLOCATE, and possibly opt-in by some specific programs.
In a filesystem with CoW and compression, the ENOSPC benefit may be lost as well.
Reviewed By: khng300
Differential Revision: https://reviews.llvm.org/D115957
Added:
Modified:
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
Removed:
################################################################################
diff --git a/llvm/cmake/config-ix.cmake b/llvm/cmake/config-ix.cmake
index fabafe10f4f01..7e9d76d6c5648 100644
--- a/llvm/cmake/config-ix.cmake
+++ b/llvm/cmake/config-ix.cmake
@@ -243,7 +243,6 @@ check_symbol_exists(setrlimit sys/resource.h HAVE_SETRLIMIT)
check_symbol_exists(isatty unistd.h HAVE_ISATTY)
check_symbol_exists(futimens sys/stat.h HAVE_FUTIMENS)
check_symbol_exists(futimes sys/time.h HAVE_FUTIMES)
-check_symbol_exists(posix_fallocate fcntl.h HAVE_POSIX_FALLOCATE)
# AddressSanitizer conflicts with lib/Support/Unix/Signals.inc
# Avoid sigaltstack on Apple platforms, where backtrace() cannot handle it
# (rdar://7089625) and _Unwind_Backtrace is unusable because it cannot unwind
diff --git a/llvm/include/llvm/Config/config.h.cmake b/llvm/include/llvm/Config/config.h.cmake
index 1d982b544a63a..064d2f27dc18b 100644
--- a/llvm/include/llvm/Config/config.h.cmake
+++ b/llvm/include/llvm/Config/config.h.cmake
@@ -152,9 +152,6 @@
/* Define to 1 if you have the `malloc_zone_statistics' function. */
#cmakedefine HAVE_MALLOC_ZONE_STATISTICS ${HAVE_MALLOC_ZONE_STATISTICS}
-/* Define to 1 if you have the `posix_fallocate' function. */
-#cmakedefine HAVE_POSIX_FALLOCATE ${HAVE_POSIX_FALLOCATE}
-
/* Define to 1 if you have the `posix_spawn' function. */
#cmakedefine HAVE_POSIX_SPAWN ${HAVE_POSIX_SPAWN}
diff --git a/llvm/lib/Support/Unix/Path.inc b/llvm/lib/Support/Unix/Path.inc
index 19d89db556273..f5cb5895d95d7 100644
--- a/llvm/lib/Support/Unix/Path.inc
+++ b/llvm/lib/Support/Unix/Path.inc
@@ -590,19 +590,6 @@ std::error_code rename(const Twine &from, const Twine &to) {
}
std::error_code resize_file(int FD, uint64_t Size) {
-#if defined(HAVE_POSIX_FALLOCATE)
- // If we have posix_fallocate use it. Unlike ftruncate it always allocates
- // space, so we get an error if the disk is full.
- if (int Err = ::posix_fallocate(FD, 0, Size)) {
-#ifdef _AIX
- constexpr int NotSupportedError = ENOTSUP;
-#else
- constexpr int NotSupportedError = EOPNOTSUPP;
-#endif
- if (Err != EINVAL && Err != NotSupportedError)
- return std::error_code(Err, std::generic_category());
- }
-#endif
// Use ftruncate as a fallback. It may or may not allocate space. At least on
// OS X with HFS+ it does.
if (::ftruncate(FD, Size) == -1)
diff --git a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
index c7d7a37a2c169..8e22f8984cf9c 100644
--- a/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
+++ b/llvm/utils/gn/secondary/llvm/include/llvm/Config/BUILD.gn
@@ -143,7 +143,6 @@ write_cmake_config("config") {
"HAVE_LINK_H=1",
"HAVE_LSEEK64=1",
"HAVE_MALLINFO=1",
- "HAVE_POSIX_FALLOCATE=1",
"HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=1",
]
} else {
@@ -152,7 +151,6 @@ write_cmake_config("config") {
"HAVE_LINK_H=",
"HAVE_LSEEK64=",
"HAVE_MALLINFO=",
- "HAVE_POSIX_FALLOCATE=",
"HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=",
]
}
diff --git a/utils/bazel/llvm-project-overlay/llvm/config.bzl b/utils/bazel/llvm-project-overlay/llvm/config.bzl
index 8750ad9cf43a5..2046b2645362f 100644
--- a/utils/bazel/llvm-project-overlay/llvm/config.bzl
+++ b/utils/bazel/llvm-project-overlay/llvm/config.bzl
@@ -43,7 +43,6 @@ linux_defines = posix_defines + [
"HAVE_LINK_H=1",
"HAVE_LSEEK64=1",
"HAVE_MALLINFO=1",
- "HAVE_POSIX_FALLOCATE=1",
"HAVE_SBRK=1",
"HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC=1",
]
diff --git a/utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h b/utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h
index e6c84b6dda2dd..4045011394947 100644
--- a/utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h
+++ b/utils/bazel/llvm-project-overlay/llvm/include/llvm/Config/config.h
@@ -165,9 +165,6 @@
/* Define to 1 if you have the `malloc_zone_statistics' function. */
/* HAVE_MALLOC_ZONE_STATISTICS defined in Bazel */
-/* Define to 1 if you have the `posix_fallocate' function. */
-/* HAVE_POSIX_FALLOCATE defined in Bazel */
-
/* Define to 1 if you have the `posix_spawn' function. */
#define HAVE_POSIX_SPAWN 1
diff --git a/utils/bazel/llvm_configs/config.h.cmake b/utils/bazel/llvm_configs/config.h.cmake
index 1d982b544a63a..064d2f27dc18b 100644
--- a/utils/bazel/llvm_configs/config.h.cmake
+++ b/utils/bazel/llvm_configs/config.h.cmake
@@ -152,9 +152,6 @@
/* Define to 1 if you have the `malloc_zone_statistics' function. */
#cmakedefine HAVE_MALLOC_ZONE_STATISTICS ${HAVE_MALLOC_ZONE_STATISTICS}
-/* Define to 1 if you have the `posix_fallocate' function. */
-#cmakedefine HAVE_POSIX_FALLOCATE ${HAVE_POSIX_FALLOCATE}
-
/* Define to 1 if you have the `posix_spawn' function. */
#cmakedefine HAVE_POSIX_SPAWN ${HAVE_POSIX_SPAWN}
More information about the llvm-commits
mailing list