gl/lib/randint.c
lib/euidaccess-stat.c
gl/tests/test-mbsalign.c
+gl/tests/test-fadvise.c
exclude
exitfail
faccessat
+ fadvise
fchdir
fcntl
fcntl-safer
--- /dev/null
+/* Declare an access pattern hint for files.
+ Copyright (C) 2010 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include "fadvise.h"
+
+#include <stdio.h>
+#include <fcntl.h>
+#include "ignore-value.h"
+
+void
+fdadvise (int fd, off_t offset, off_t len, fadvice_t advice)
+{
+#if HAVE_POSIX_FADVISE
+ ignore_value (posix_fadvise (fd, offset, len, advice));
+#endif
+}
+
+void
+fadvise (FILE *fp, fadvice_t advice)
+{
+ if (fp)
+ fdadvise (fileno (fp), 0, 0, advice);
+}
--- /dev/null
+/* Declare an access pattern hint for files.
+ Copyright (C) 2010 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <sys/types.h>
+
+/* There are a few hints one can provide, which have the
+ following characteristics on Linux 2.6.31 at least.
+
+ POSIX_FADV_SEQUENTIAL
+ Doubles the size of read ahead done for file
+ POSIX_FADV_WILLNEED
+ _synchronously_ prepopulate the buffer cache with the file
+ POSIX_FADV_NOREUSE
+ Could lower priority of data in buffer caches,
+ but currently does nothing.
+ POSIX_FADV_DONTNEED
+ Drop the file from cache.
+ Note this is automatically done when files are unlinked.
+
+ We use this enum "type" both to make it explicit that
+ these options are mutually exclusive, and to discourage
+ the passing of the possibly undefined POSIX_FADV_... values.
+ Note we could #undef the POSIX_FADV_ values, but that would
+ preclude using the posix_fadvise() function with its standard
+ constants. Using posix_fadvise() might be required if the return
+ value is needed, but it must be guarded by appropriate #ifdefs. */
+
+#if HAVE_POSIX_FADVISE
+typedef enum {
+ FADVISE_NORMAL = POSIX_FADV_NORMAL,
+ FADVISE_SEQUENTIAL = POSIX_FADV_SEQUENTIAL,
+ FADVISE_NOREUSE = POSIX_FADV_NOREUSE,
+ FADVISE_DONTNEED = POSIX_FADV_DONTNEED,
+ FADVISE_WILLNEED = POSIX_FADV_WILLNEED,
+ FADVISE_RANDOM = POSIX_FADV_RANDOM,
+} fadvice_t;
+#else
+typedef enum {
+ FADVISE_NORMAL,
+ FADVISE_SEQUENTIAL,
+ FADVISE_NOREUSE,
+ FADVISE_DONTNEED,
+ FADVISE_WILLNEED,
+ FADVISE_RANDOM,
+} fadvice_t;
+#endif
+
+/* We ignore any errors as these hints are only advisory.
+ There is the chance one can pass invalid ADVICE, which will
+ not be indicated, but given the simplicity of the interface
+ this is unlikely. Also not returning errors allows the
+ unconditional passing of descriptors to non standard files,
+ which will just be ignored if unsupported. */
+
+void fdadvise (int fd, off_t offset, off_t len, fadvice_t advice);
+void fadvise (FILE *fp, fadvice_t advice);
--- /dev/null
+Description:
+Declare an access pattern hint for files.
+
+Files:
+lib/fadvise.c
+lib/fadvise.h
+
+Depends-on:
+ignore-value
+
+configure.ac:
+AC_CHECK_FUNCS_ONCE([posix_fadvise])
+
+Makefile.am:
+lib_SOURCES += fadvise.c fadvise.h
+
+Include:
+"fadvise.h"
+
+License:
+LGPL
+
+Maintainer:
+Pádraig Brady
--- /dev/null
+/* Test that fadvise works as advertised.
+ Copyright (C) 2010 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Pádraig Brady. */
+
+#include <config.h>
+#include <stdio.h>
+
+#include "fadvise.h"
+
+int
+main (void)
+{
+ /* Valid. */
+ fadvise (stdin, FADVISE_SEQUENTIAL);
+ fdadvise (fileno (stdin), 0, 0, FADVISE_RANDOM);
+
+ /* Ignored. */
+ fadvise (NULL, FADVISE_RANDOM);
+
+ /* Invalid. */
+ fdadvise (42, 0, 0, FADVISE_RANDOM);
+ /* Unfortunately C enums are not types.
+ One could hack type safety by wrapping in a struct,
+ but it's probably not worth the complexity in this case. */
+ fadvise (stdin, FADVISE_SEQUENTIAL + FADVISE_RANDOM);
+ fadvise (stdin, 4242);
+
+ return 0;
+}
LIBS=$coreutils_saved_libs
# Used by sort.c.
- AC_CHECK_FUNCS_ONCE([posix_fadvise])
AC_CHECK_FUNCS_ONCE([nl_langinfo])
# Used by tail.c.
#include "system.h"
#include "close-stream.h"
#include "error.h"
+#include "fadvise.h"
#include "fd-reopen.h"
#include "gethrxtime.h"
#include "human.h"
-#include "ignore-value.h"
#include "long-options.h"
#include "quote.h"
#include "quotearg.h"
posix_fadvise to tell the system not to pollute the buffer
cache with this data. Don't bother to diagnose lseek or
posix_fadvise failure. */
-#ifdef POSIX_FADV_DONTNEED
off_t off = lseek (STDOUT_FILENO, 0, SEEK_CUR);
if (0 <= off)
- ignore_value (posix_fadvise (STDOUT_FILENO,
- off, 0, POSIX_FADV_DONTNEED));
-#endif
+ fdadvise (STDOUT_FILENO, off, 0, FADVISE_DONTNEED);
/* Attempt to ensure that that final block is committed
to disk as quickly as possible. */
#include "system.h"
#include "argmatch.h"
#include "error.h"
+#include "fadvise.h"
#include "filevercmp.h"
#include "hard-locale.h"
#include "hash.h"
#include "heap.h"
-#include "ignore-value.h"
#include "md5.h"
#include "mbswidth.h"
#include "nproc.h"
return node;
}
-/* Predeclare an access pattern for input files.
- Ignore any errors -- this is only advisory.
+/* Return a stream for FILE, opened with mode HOW. A null FILE means
+ standard output; HOW should be "w". When opening for input, "-"
+ means standard input. To avoid confusion, do not return file
+ descriptors STDIN_FILENO, STDOUT_FILENO, or STDERR_FILENO when
+ opening an ordinary FILE. Return NULL if unsuccessful.
+ fadvise() is used to specify an access pattern for input files.
There are a few hints we could possibly provide,
and after careful testing it was decided that
specifying POSIX_FADV_SEQUENTIAL was not detrimental
cache immediately after processing. This is done implicitly
however when the files are unlinked. */
-static void
-fadvise_input (FILE *fp)
-{
-#if HAVE_POSIX_FADVISE
- if (fp)
- {
- int fd = fileno (fp);
- ignore_value (posix_fadvise (fd, 0, 0, POSIX_FADV_SEQUENTIAL));
- }
-#endif
-}
-
-/* Return a stream for FILE, opened with mode HOW. A null FILE means
- standard output; HOW should be "w". When opening for input, "-"
- means standard input. To avoid confusion, do not return file
- descriptors STDIN_FILENO, STDOUT_FILENO, or STDERR_FILENO when
- opening an ordinary FILE. Return NULL if unsuccessful. */
-
static FILE *
stream_open (const char *file, const char *how)
{
}
else
fp = fopen (file, how);
- fadvise_input (fp);
+ fadvise (fp, FADVISE_SEQUENTIAL);
return fp;
}
return fopen (file, how);
projects / platform / upstream / coreutils.git / commitdiff