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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.181 by root, Tue May 4 21:14:01 2010 UTC vs.
Revision 1.240 by root, Mon Dec 17 06:18:39 2012 UTC

168use common::sense; 168use common::sense;
169 169
170use base 'Exporter'; 170use base 'Exporter';
171 171
172BEGIN { 172BEGIN {
173 our $VERSION = '3.65'; 173 our $VERSION = '4.18';
174 174
175 our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close 175 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx 176 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_sync aio_fsync 177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178 aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead 178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate
179 aio_pathsync aio_readahead aio_fiemap
179 aio_rename aio_link aio_move aio_copy aio_group 180 aio_rename aio_link aio_move aio_copy aio_group
180 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
181 aio_chmod aio_utime aio_truncate 182 aio_chmod aio_utime aio_truncate
182 aio_msync aio_mtouch aio_statvfs); 183 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs
185 aio_wd);
183 186
184 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
185 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
186 min_parallel max_parallel max_idle 189 min_parallel max_parallel max_idle idle_timeout
187 nreqs nready npending nthreads 190 nreqs nready npending nthreads
188 max_poll_time max_poll_reqs 191 max_poll_time max_poll_reqs
189 sendfile fadvise); 192 sendfile fadvise madvise
193 mmap munmap munlock munlockall);
190 194
191 push @AIO_REQ, qw(aio_busy); # not exported 195 push @AIO_REQ, qw(aio_busy); # not exported
192 196
193 @IO::AIO::GRP::ISA = 'IO::AIO::REQ'; 197 @IO::AIO::GRP::ISA = 'IO::AIO::REQ';
194 198
198 202
199=head1 FUNCTIONS 203=head1 FUNCTIONS
200 204
201=head2 QUICK OVERVIEW 205=head2 QUICK OVERVIEW
202 206
203This section simply lists the prototypes of the most important functions 207This section simply lists the prototypes most of the functions for
204for quick reference. See the following sections for function-by-function 208quick reference. See the following sections for function-by-function
205documentation. 209documentation.
206 210
211 aio_wd $pathname, $callback->($wd)
207 aio_open $pathname, $flags, $mode, $callback->($fh) 212 aio_open $pathname, $flags, $mode, $callback->($fh)
208 aio_close $fh, $callback->($status) 213 aio_close $fh, $callback->($status)
214 aio_seek $fh,$offset,$whence, $callback->($offs)
209 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 215 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
210 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 216 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
211 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 217 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
212 aio_readahead $fh,$offset,$length, $callback->($retval) 218 aio_readahead $fh,$offset,$length, $callback->($retval)
213 aio_stat $fh_or_path, $callback->($status) 219 aio_stat $fh_or_path, $callback->($status)
214 aio_lstat $fh, $callback->($status) 220 aio_lstat $fh, $callback->($status)
215 aio_statvfs $fh_or_path, $callback->($statvfs) 221 aio_statvfs $fh_or_path, $callback->($statvfs)
216 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 222 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
217 aio_chown $fh_or_path, $uid, $gid, $callback->($status) 223 aio_chown $fh_or_path, $uid, $gid, $callback->($status)
224 aio_chmod $fh_or_path, $mode, $callback->($status)
218 aio_truncate $fh_or_path, $offset, $callback->($status) 225 aio_truncate $fh_or_path, $offset, $callback->($status)
219 aio_chmod $fh_or_path, $mode, $callback->($status) 226 aio_allocate $fh, $mode, $offset, $len, $callback->($status)
227 aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
220 aio_unlink $pathname, $callback->($status) 228 aio_unlink $pathname, $callback->($status)
221 aio_mknod $path, $mode, $dev, $callback->($status) 229 aio_mknod $pathname, $mode, $dev, $callback->($status)
222 aio_link $srcpath, $dstpath, $callback->($status) 230 aio_link $srcpath, $dstpath, $callback->($status)
223 aio_symlink $srcpath, $dstpath, $callback->($status) 231 aio_symlink $srcpath, $dstpath, $callback->($status)
224 aio_readlink $path, $callback->($link) 232 aio_readlink $pathname, $callback->($link)
233 aio_realpath $pathname, $callback->($link)
225 aio_rename $srcpath, $dstpath, $callback->($status) 234 aio_rename $srcpath, $dstpath, $callback->($status)
226 aio_mkdir $pathname, $mode, $callback->($status) 235 aio_mkdir $pathname, $mode, $callback->($status)
227 aio_rmdir $pathname, $callback->($status) 236 aio_rmdir $pathname, $callback->($status)
228 aio_readdir $pathname, $callback->($entries) 237 aio_readdir $pathname, $callback->($entries)
229 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 238 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
230 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 239 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
231 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN 240 IO::AIO::READDIR_STAT_ORDER IO::AIO::READDIR_FOUND_UNKNOWN
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
232 aio_load $path, $data, $callback->($status) 242 aio_load $pathname, $data, $callback->($status)
233 aio_copy $srcpath, $dstpath, $callback->($status) 243 aio_copy $srcpath, $dstpath, $callback->($status)
234 aio_move $srcpath, $dstpath, $callback->($status) 244 aio_move $srcpath, $dstpath, $callback->($status)
235 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
236 aio_rmtree $path, $callback->($status) 245 aio_rmtree $pathname, $callback->($status)
237 aio_sync $callback->($status) 246 aio_sync $callback->($status)
247 aio_syncfs $fh, $callback->($status)
238 aio_fsync $fh, $callback->($status) 248 aio_fsync $fh, $callback->($status)
239 aio_fdatasync $fh, $callback->($status) 249 aio_fdatasync $fh, $callback->($status)
240 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 250 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
241 aio_pathsync $path, $callback->($status) 251 aio_pathsync $pathname, $callback->($status)
242 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 252 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
243 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 253 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
254 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
255 aio_mlockall $flags, $callback->($status)
244 aio_group $callback->(...) 256 aio_group $callback->(...)
245 aio_nop $callback->() 257 aio_nop $callback->()
246 258
247 $prev_pri = aioreq_pri [$pri] 259 $prev_pri = aioreq_pri [$pri]
248 aioreq_nice $pri_adjust 260 aioreq_nice $pri_adjust
254 IO::AIO::max_poll_reqs $nreqs 266 IO::AIO::max_poll_reqs $nreqs
255 IO::AIO::max_poll_time $seconds 267 IO::AIO::max_poll_time $seconds
256 IO::AIO::min_parallel $nthreads 268 IO::AIO::min_parallel $nthreads
257 IO::AIO::max_parallel $nthreads 269 IO::AIO::max_parallel $nthreads
258 IO::AIO::max_idle $nthreads 270 IO::AIO::max_idle $nthreads
271 IO::AIO::idle_timeout $seconds
259 IO::AIO::max_outstanding $maxreqs 272 IO::AIO::max_outstanding $maxreqs
260 IO::AIO::nreqs 273 IO::AIO::nreqs
261 IO::AIO::nready 274 IO::AIO::nready
262 IO::AIO::npending 275 IO::AIO::npending
263 276
264 IO::AIO::sendfile $ofh, $ifh, $offset, $count 277 IO::AIO::sendfile $ofh, $ifh, $offset, $count
265 IO::AIO::fadvise $fh, $offset, $len, $advice 278 IO::AIO::fadvise $fh, $offset, $len, $advice
266 IO::AIO::mlockall $flags 279 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280 IO::AIO::munmap $scalar
281 IO::AIO::madvise $scalar, $offset, $length, $advice
282 IO::AIO::mprotect $scalar, $offset, $length, $protect
283 IO::AIO::munlock $scalar, $offset = 0, $length = undef
267 IO::AIO::munlockall 284 IO::AIO::munlockall
268 285
269=head2 AIO REQUEST FUNCTIONS 286=head2 API NOTES
270 287
271All the C<aio_*> calls are more or less thin wrappers around the syscall 288All the C<aio_*> calls are more or less thin wrappers around the syscall
272with the same name (sans C<aio_>). The arguments are similar or identical, 289with the same name (sans C<aio_>). The arguments are similar or identical,
273and they all accept an additional (and optional) C<$callback> argument 290and they all accept an additional (and optional) C<$callback> argument
274which must be a code reference. This code reference will get called with 291which must be a code reference. This code reference will be called after
275the syscall return code (e.g. most syscalls return C<-1> on error, unlike 292the syscall has been executed in an asynchronous fashion. The results
276perl, which usually delivers "false") as its sole argument after the given 293of the request will be passed as arguments to the callback (and, if an
277syscall has been executed asynchronously. 294error occured, in C<$!>) - for most requests the syscall return code (e.g.
295most syscalls return C<-1> on error, unlike perl, which usually delivers
296"false").
297
298Some requests (such as C<aio_readdir>) pass the actual results and
299communicate failures by passing C<undef>.
278 300
279All functions expecting a filehandle keep a copy of the filehandle 301All functions expecting a filehandle keep a copy of the filehandle
280internally until the request has finished. 302internally until the request has finished.
281 303
282All functions return request objects of type L<IO::AIO::REQ> that allow 304All functions return request objects of type L<IO::AIO::REQ> that allow
283further manipulation of those requests while they are in-flight. 305further manipulation of those requests while they are in-flight.
284 306
285The pathnames you pass to these routines I<must> be absolute and 307The pathnames you pass to these routines I<should> be absolute. The
286encoded as octets. The reason for the former is that at the time the 308reason for this is that at the time the request is being executed, the
287request is being executed, the current working directory could have 309current working directory could have changed. Alternatively, you can
288changed. Alternatively, you can make sure that you never change the 310make sure that you never change the current working directory anywhere
289current working directory anywhere in the program and then use relative 311in the program and then use relative paths. You can also take advantage
290paths. 312of IO::AIOs working directory abstraction, that lets you specify paths
313relative to some previously-opened "working directory object" - see the
314description of the C<IO::AIO::WD> class later in this document.
291 315
292To encode pathnames as octets, either make sure you either: a) always pass 316To encode pathnames as octets, either make sure you either: a) always pass
293in filenames you got from outside (command line, readdir etc.) without 317in filenames you got from outside (command line, readdir etc.) without
294tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode 318tinkering, b) are in your native filesystem encoding, c) use the Encode
295your pathnames to the locale (or other) encoding in effect in the user 319module and encode your pathnames to the locale (or other) encoding in
296environment, d) use Glib::filename_from_unicode on unicode filenames or e) 320effect in the user environment, d) use Glib::filename_from_unicode on
297use something else to ensure your scalar has the correct contents. 321unicode filenames or e) use something else to ensure your scalar has the
322correct contents.
298 323
299This works, btw. independent of the internal UTF-8 bit, which IO::AIO 324This works, btw. independent of the internal UTF-8 bit, which IO::AIO
300handles correctly whether it is set or not. 325handles correctly whether it is set or not.
326
327=head2 AIO REQUEST FUNCTIONS
301 328
302=over 4 329=over 4
303 330
304=item $prev_pri = aioreq_pri [$pri] 331=item $prev_pri = aioreq_pri [$pri]
305 332
335 362
336 363
337=item aio_open $pathname, $flags, $mode, $callback->($fh) 364=item aio_open $pathname, $flags, $mode, $callback->($fh)
338 365
339Asynchronously open or create a file and call the callback with a newly 366Asynchronously open or create a file and call the callback with a newly
340created filehandle for the file. 367created filehandle for the file (or C<undef> in case of an error).
341 368
342The pathname passed to C<aio_open> must be absolute. See API NOTES, above, 369The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
343for an explanation. 370for an explanation.
344 371
345The C<$flags> argument is a bitmask. See the C<Fcntl> module for a 372The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
361 } else { 388 } else {
362 die "open failed: $!\n"; 389 die "open failed: $!\n";
363 } 390 }
364 }; 391 };
365 392
393In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
394C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
395following POSIX and non-POSIX constants are available (missing ones on
396your system are, as usual, C<0>):
397
398C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
399C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
400C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
401
366 402
367=item aio_close $fh, $callback->($status) 403=item aio_close $fh, $callback->($status)
368 404
369Asynchronously close a file and call the callback with the result 405Asynchronously close a file and call the callback with the result
370code. 406code.
378 414
379Or in other words: the file descriptor will be closed, but it will not be 415Or in other words: the file descriptor will be closed, but it will not be
380free for reuse until the perl filehandle is closed. 416free for reuse until the perl filehandle is closed.
381 417
382=cut 418=cut
419
420=item aio_seek $fh, $offset, $whence, $callback->($offs)
421
422Seeks the filehandle to the new C<$offset>, similarly to perl's
423C<sysseek>. The C<$whence> can use the traditional values (C<0> for
424C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
425C<IO::AIO::SEEK_END>).
426
427The resulting absolute offset will be passed to the callback, or C<-1> in
428case of an error.
429
430In theory, the C<$whence> constants could be different than the
431corresponding values from L<Fcntl>, but perl guarantees they are the same,
432so don't panic.
433
434As a GNU/Linux (and maybe Solaris) extension, also the constants
435C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
436could be found. No guarantees about suitability for use in C<aio_seek> or
437Perl's C<sysseek> can be made though, although I would naively assume they
438"just work".
383 439
384=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
385 441
386=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
387 443
420 476
421Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts 477Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
422reading at byte offset C<$in_offset>, and starts writing at the current 478reading at byte offset C<$in_offset>, and starts writing at the current
423file offset of C<$out_fh>. Because of that, it is not safe to issue more 479file offset of C<$out_fh>. Because of that, it is not safe to issue more
424than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each 480than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
425other. 481other. The same C<$in_fh> works fine though, as this function does not
482move or use the file offset of C<$in_fh>.
426 483
484Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
485are written, and there is no way to find out how many more bytes have been
486read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
487number of bytes written to C<$out_fh>. Only if the result value equals
488C<$length> one can assume that C<$length> bytes have been read.
489
490Unlike with other C<aio_> functions, it makes a lot of sense to use
491C<aio_sendfile> on non-blocking sockets, as long as one end (typically
492the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
493the socket I/O will be non-blocking. Note, however, that you can run
494into a trap where C<aio_sendfile> reads some data with readahead, then
495fails to write all data, and when the socket is ready the next time, the
496data in the cache is already lost, forcing C<aio_sendfile> to again hit
497the disk. Explicit C<aio_read> + C<aio_write> let's you better control
498resource usage.
499
427This call tries to make use of a native C<sendfile> syscall to provide 500This call tries to make use of a native C<sendfile>-like syscall to
428zero-copy operation. For this to work, C<$out_fh> should refer to a 501provide zero-copy operation. For this to work, C<$out_fh> should refer to
429socket, and C<$in_fh> should refer to an mmap'able file. 502a socket, and C<$in_fh> should refer to an mmap'able file.
430 503
431If a native sendfile cannot be found or it fails with C<ENOSYS>, 504If a native sendfile cannot be found or it fails with C<ENOSYS>,
432C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>, 505C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
433it will be emulated, so you can call C<aio_sendfile> on any type of 506C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
434filehandle regardless of the limitations of the operating system. 507type of filehandle regardless of the limitations of the operating system.
435 508
436Please note, however, that C<aio_sendfile> can read more bytes from 509As native sendfile syscalls (as practically any non-POSIX interface hacked
437C<$in_fh> than are written, and there is no way to find out how many 510together in a hurry to improve benchmark numbers) tend to be rather buggy
438bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only 511on many systems, this implementation tries to work around some known bugs
439provides the number of bytes written to C<$out_fh>. Only if the result 512in Linux and FreeBSD kernels (probably others, too), but that might fail,
440value equals C<$length> one can assume that C<$length> bytes have been 513so you really really should check the return value of C<aio_sendfile> -
441read. 514fewre bytes than expected might have been transferred.
442 515
443 516
444=item aio_readahead $fh,$offset,$length, $callback->($retval) 517=item aio_readahead $fh,$offset,$length, $callback->($retval)
445 518
446C<aio_readahead> populates the page cache with data from a file so that 519C<aio_readahead> populates the page cache with data from a file so that
468for an explanation. 541for an explanation.
469 542
470Currently, the stats are always 64-bit-stats, i.e. instead of returning an 543Currently, the stats are always 64-bit-stats, i.e. instead of returning an
471error when stat'ing a large file, the results will be silently truncated 544error when stat'ing a large file, the results will be silently truncated
472unless perl itself is compiled with large file support. 545unless perl itself is compiled with large file support.
546
547To help interpret the mode and dev/rdev stat values, IO::AIO offers the
548following constants and functions (if not implemented, the constants will
549be C<0> and the functions will either C<croak> or fall back on traditional
550behaviour).
551
552C<S_IFMT>, C<S_IFIFO>, C<S_IFCHR>, C<S_IFBLK>, C<S_IFLNK>, C<S_IFREG>,
553C<S_IFDIR>, C<S_IFWHT>, C<S_IFSOCK>, C<IO::AIO::major $dev_t>,
554C<IO::AIO::minor $dev_t>, C<IO::AIO::makedev $major, $minor>.
473 555
474Example: Print the length of F</etc/passwd>: 556Example: Print the length of F</etc/passwd>:
475 557
476 aio_stat "/etc/passwd", sub { 558 aio_stat "/etc/passwd", sub {
477 $_[0] and die "stat failed: $!"; 559 $_[0] and die "stat failed: $!";
521 namemax => 255, 603 namemax => 255,
522 frsize => 1024, 604 frsize => 1024,
523 fsid => 1810 605 fsid => 1810
524 } 606 }
525 607
608Here is a (likely partial) list of fsid values used by Linux - it is safe
609to hardcode these when the $^O is C<linux>:
610
611 0x0000adf5 adfs
612 0x0000adff affs
613 0x5346414f afs
614 0x09041934 anon-inode filesystem
615 0x00000187 autofs
616 0x42465331 befs
617 0x1badface bfs
618 0x42494e4d binfmt_misc
619 0x9123683e btrfs
620 0x0027e0eb cgroupfs
621 0xff534d42 cifs
622 0x73757245 coda
623 0x012ff7b7 coh
624 0x28cd3d45 cramfs
625 0x453dcd28 cramfs-wend (wrong endianness)
626 0x64626720 debugfs
627 0x00001373 devfs
628 0x00001cd1 devpts
629 0x0000f15f ecryptfs
630 0x00414a53 efs
631 0x0000137d ext
632 0x0000ef53 ext2/ext3
633 0x0000ef51 ext2
634 0x00004006 fat
635 0x65735546 fuseblk
636 0x65735543 fusectl
637 0x0bad1dea futexfs
638 0x01161970 gfs2
639 0x47504653 gpfs
640 0x00004244 hfs
641 0xf995e849 hpfs
642 0x958458f6 hugetlbfs
643 0x2bad1dea inotifyfs
644 0x00009660 isofs
645 0x000072b6 jffs2
646 0x3153464a jfs
647 0x6b414653 k-afs
648 0x0bd00bd0 lustre
649 0x0000137f minix
650 0x0000138f minix 30 char names
651 0x00002468 minix v2
652 0x00002478 minix v2 30 char names
653 0x00004d5a minix v3
654 0x19800202 mqueue
655 0x00004d44 msdos
656 0x0000564c novell
657 0x00006969 nfs
658 0x6e667364 nfsd
659 0x00003434 nilfs
660 0x5346544e ntfs
661 0x00009fa1 openprom
662 0x7461636F ocfs2
663 0x00009fa0 proc
664 0x6165676c pstorefs
665 0x0000002f qnx4
666 0x858458f6 ramfs
667 0x52654973 reiserfs
668 0x00007275 romfs
669 0x67596969 rpc_pipefs
670 0x73636673 securityfs
671 0xf97cff8c selinux
672 0x0000517b smb
673 0x534f434b sockfs
674 0x73717368 squashfs
675 0x62656572 sysfs
676 0x012ff7b6 sysv2
677 0x012ff7b5 sysv4
678 0x01021994 tmpfs
679 0x15013346 udf
680 0x00011954 ufs
681 0x54190100 ufs byteswapped
682 0x00009fa2 usbdevfs
683 0x01021997 v9fs
684 0xa501fcf5 vxfs
685 0xabba1974 xenfs
686 0x012ff7b4 xenix
687 0x58465342 xfs
688 0x012fd16d xia
526 689
527=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 690=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
528 691
529Works like perl's C<utime> function (including the special case of $atime 692Works like perl's C<utime> function (including the special case of $atime
530and $mtime being undef). Fractional times are supported if the underlying 693and $mtime being undef). Fractional times are supported if the underlying
558=item aio_truncate $fh_or_path, $offset, $callback->($status) 721=item aio_truncate $fh_or_path, $offset, $callback->($status)
559 722
560Works like truncate(2) or ftruncate(2). 723Works like truncate(2) or ftruncate(2).
561 724
562 725
726=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
727
728Allocates or freed disk space according to the C<$mode> argument. See the
729linux C<fallocate> docuemntation for details.
730
731C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
732to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE |
733IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
734
735The file system block size used by C<fallocate> is presumably the
736C<f_bsize> returned by C<statvfs>.
737
738If C<fallocate> isn't available or cannot be emulated (currently no
739emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
740
741
563=item aio_chmod $fh_or_path, $mode, $callback->($status) 742=item aio_chmod $fh_or_path, $mode, $callback->($status)
564 743
565Works like perl's C<chmod> function. 744Works like perl's C<chmod> function.
566 745
567 746
569 748
570Asynchronously unlink (delete) a file and call the callback with the 749Asynchronously unlink (delete) a file and call the callback with the
571result code. 750result code.
572 751
573 752
574=item aio_mknod $path, $mode, $dev, $callback->($status) 753=item aio_mknod $pathname, $mode, $dev, $callback->($status)
575 754
576[EXPERIMENTAL] 755[EXPERIMENTAL]
577 756
578Asynchronously create a device node (or fifo). See mknod(2). 757Asynchronously create a device node (or fifo). See mknod(2).
579 758
580The only (POSIX-) portable way of calling this function is: 759The only (POSIX-) portable way of calling this function is:
581 760
582 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 761 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
583 762
763See C<aio_stat> for info about some potentially helpful extra constants
764and functions.
584 765
585=item aio_link $srcpath, $dstpath, $callback->($status) 766=item aio_link $srcpath, $dstpath, $callback->($status)
586 767
587Asynchronously create a new link to the existing object at C<$srcpath> at 768Asynchronously create a new link to the existing object at C<$srcpath> at
588the path C<$dstpath> and call the callback with the result code. 769the path C<$dstpath> and call the callback with the result code.
592 773
593Asynchronously create a new symbolic link to the existing object at C<$srcpath> at 774Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
594the path C<$dstpath> and call the callback with the result code. 775the path C<$dstpath> and call the callback with the result code.
595 776
596 777
597=item aio_readlink $path, $callback->($link) 778=item aio_readlink $pathname, $callback->($link)
598 779
599Asynchronously read the symlink specified by C<$path> and pass it to 780Asynchronously read the symlink specified by C<$path> and pass it to
600the callback. If an error occurs, nothing or undef gets passed to the 781the callback. If an error occurs, nothing or undef gets passed to the
601callback. 782callback.
602 783
603 784
785=item aio_realpath $pathname, $callback->($path)
786
787Asynchronously make the path absolute and resolve any symlinks in
788C<$path>. The resulting path only consists of directories (same as
789L<Cwd::realpath>).
790
791This request can be used to get the absolute path of the current working
792directory by passing it a path of F<.> (a single dot).
793
794
604=item aio_rename $srcpath, $dstpath, $callback->($status) 795=item aio_rename $srcpath, $dstpath, $callback->($status)
605 796
606Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 797Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
607rename(2) and call the callback with the result code. 798rename(2) and call the callback with the result code.
608 799
630array-ref with the filenames. 821array-ref with the filenames.
631 822
632 823
633=item aio_readdirx $pathname, $flags, $callback->($entries, $flags) 824=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
634 825
635Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune 826Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
636behaviour and output format. In case of an error, C<$entries> will be 827tune behaviour and output format. In case of an error, C<$entries> will be
637C<undef>. 828C<undef>.
638 829
639The flags are a combination of the following constants, ORed together (the 830The flags are a combination of the following constants, ORed together (the
640flags will also be passed to the callback, possibly modified): 831flags will also be passed to the callback, possibly modified):
641 832
642=over 4 833=over 4
643 834
644=item IO::AIO::READDIR_DENTS 835=item IO::AIO::READDIR_DENTS
645 836
646When this flag is off, then the callback gets an arrayref with of names 837When this flag is off, then the callback gets an arrayref consisting of
647only (as with C<aio_readdir>), otherwise it gets an arrayref with 838names only (as with C<aio_readdir>), otherwise it gets an arrayref with
648C<[$name, $type, $inode]> arrayrefs, each describing a single directory 839C<[$name, $type, $inode]> arrayrefs, each describing a single directory
649entry in more detail. 840entry in more detail.
650 841
651C<$name> is the name of the entry. 842C<$name> is the name of the entry.
652 843
665systems that do not deliver the inode information. 856systems that do not deliver the inode information.
666 857
667=item IO::AIO::READDIR_DIRS_FIRST 858=item IO::AIO::READDIR_DIRS_FIRST
668 859
669When this flag is set, then the names will be returned in an order where 860When this flag is set, then the names will be returned in an order where
670likely directories come first. This is useful when you need to quickly 861likely directories come first, in optimal stat order. This is useful when
671find directories, or you want to find all directories while avoiding to 862you need to quickly find directories, or you want to find all directories
672stat() each entry. 863while avoiding to stat() each entry.
673 864
674If the system returns type information in readdir, then this is used 865If the system returns type information in readdir, then this is used
675to find directories directly. Otherwise, likely directories are files 866to find directories directly. Otherwise, likely directories are names
676beginning with ".", or otherwise files with no dots, of which files with 867beginning with ".", or otherwise names with no dots, of which names with
677short names are tried first. 868short names are tried first.
678 869
679=item IO::AIO::READDIR_STAT_ORDER 870=item IO::AIO::READDIR_STAT_ORDER
680 871
681When this flag is set, then the names will be returned in an order 872When this flag is set, then the names will be returned in an order
688 879
689=item IO::AIO::READDIR_FOUND_UNKNOWN 880=item IO::AIO::READDIR_FOUND_UNKNOWN
690 881
691This flag should not be set when calling C<aio_readdirx>. Instead, it 882This flag should not be set when calling C<aio_readdirx>. Instead, it
692is being set by C<aio_readdirx>, when any of the C<$type>'s found were 883is being set by C<aio_readdirx>, when any of the C<$type>'s found were
693C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all 884C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
694C<$type>'s are known, which can be used to speed up some algorithms. 885C<$type>'s are known, which can be used to speed up some algorithms.
695 886
696=back 887=back
697 888
698 889
699=item aio_load $path, $data, $callback->($status) 890=item aio_load $pathname, $data, $callback->($status)
700 891
701This is a composite request that tries to fully load the given file into 892This is a composite request that tries to fully load the given file into
702memory. Status is the same as with aio_read. 893memory. Status is the same as with aio_read.
703 894
704=cut 895=cut
826 if ($_[0] && $! == EXDEV) { 1017 if ($_[0] && $! == EXDEV) {
827 aioreq_pri $pri; 1018 aioreq_pri $pri;
828 add $grp aio_copy $src, $dst, sub { 1019 add $grp aio_copy $src, $dst, sub {
829 $grp->result ($_[0]); 1020 $grp->result ($_[0]);
830 1021
831 if (!$_[0]) { 1022 unless ($_[0]) {
832 aioreq_pri $pri; 1023 aioreq_pri $pri;
833 add $grp aio_unlink $src; 1024 add $grp aio_unlink $src;
834 } 1025 }
835 }; 1026 };
836 } else { 1027 } else {
839 }; 1030 };
840 1031
841 $grp 1032 $grp
842} 1033}
843 1034
844=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 1035=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
845 1036
846Scans a directory (similar to C<aio_readdir>) but additionally tries to 1037Scans a directory (similar to C<aio_readdir>) but additionally tries to
847efficiently separate the entries of directory C<$path> into two sets of 1038efficiently separate the entries of directory C<$path> into two sets of
848names, directories you can recurse into (directories), and ones you cannot 1039names, directories you can recurse into (directories), and ones you cannot
849recurse into (everything else, including symlinks to directories). 1040recurse into (everything else, including symlinks to directories).
880Then entries will be sorted into likely directories a non-initial dot 1071Then entries will be sorted into likely directories a non-initial dot
881currently) and likely non-directories (see C<aio_readdirx>). Then every 1072currently) and likely non-directories (see C<aio_readdirx>). Then every
882entry plus an appended C</.> will be C<stat>'ed, likely directories first, 1073entry plus an appended C</.> will be C<stat>'ed, likely directories first,
883in order of their inode numbers. If that succeeds, it assumes that the 1074in order of their inode numbers. If that succeeds, it assumes that the
884entry is a directory or a symlink to directory (which will be checked 1075entry is a directory or a symlink to directory (which will be checked
885seperately). This is often faster than stat'ing the entry itself because 1076separately). This is often faster than stat'ing the entry itself because
886filesystems might detect the type of the entry without reading the inode 1077filesystems might detect the type of the entry without reading the inode
887data (e.g. ext2fs filetype feature), even on systems that cannot return 1078data (e.g. ext2fs filetype feature), even on systems that cannot return
888the filetype information on readdir. 1079the filetype information on readdir.
889 1080
890If the known number of directories (link count - 2) has been reached, the 1081If the known number of directories (link count - 2) has been reached, the
906 1097
907 my $grp = aio_group $cb; 1098 my $grp = aio_group $cb;
908 1099
909 $maxreq = 4 if $maxreq <= 0; 1100 $maxreq = 4 if $maxreq <= 0;
910 1101
911 # stat once 1102 # get a wd object
912 aioreq_pri $pri; 1103 aioreq_pri $pri;
913 add $grp aio_stat $path, sub { 1104 add $grp aio_wd $path, sub {
1105 $_[0]
914 return $grp->result () if $_[0]; 1106 or return $grp->result ();
915 my $now = time;
916 my $hash1 = join ":", (stat _)[0,1,3,7,9];
917 1107
918 # read the directory entries 1108 my $wd = [shift, "."];
1109
1110 # stat once
919 aioreq_pri $pri; 1111 aioreq_pri $pri;
920 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 1112 add $grp aio_stat $wd, sub {
921 my $entries = shift
922 or return $grp->result (); 1113 return $grp->result () if $_[0];
1114 my $now = time;
1115 my $hash1 = join ":", (stat _)[0,1,3,7,9];
923 1116
924 # stat the dir another time 1117 # read the directory entries
925 aioreq_pri $pri; 1118 aioreq_pri $pri;
1119 add $grp aio_readdirx $wd, READDIR_DIRS_FIRST, sub {
1120 my $entries = shift
1121 or return $grp->result ();
1122
1123 # stat the dir another time
1124 aioreq_pri $pri;
926 add $grp aio_stat $path, sub { 1125 add $grp aio_stat $wd, sub {
927 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1126 my $hash2 = join ":", (stat _)[0,1,3,7,9];
928 1127
929 my $ndirs; 1128 my $ndirs;
930 1129
931 # take the slow route if anything looks fishy 1130 # take the slow route if anything looks fishy
932 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1131 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
933 $ndirs = -1; 1132 $ndirs = -1;
934 } else { 1133 } else {
935 # if nlink == 2, we are finished 1134 # if nlink == 2, we are finished
936 # for non-posix-fs's, we rely on nlink < 2 1135 # for non-posix-fs's, we rely on nlink < 2
937 $ndirs = (stat _)[3] - 2 1136 $ndirs = (stat _)[3] - 2
938 or return $grp->result ([], $entries); 1137 or return $grp->result ([], $entries);
939 } 1138 }
940 1139
941 my (@dirs, @nondirs); 1140 my (@dirs, @nondirs);
942 1141
943 my $statgrp = add $grp aio_group sub { 1142 my $statgrp = add $grp aio_group sub {
944 $grp->result (\@dirs, \@nondirs); 1143 $grp->result (\@dirs, \@nondirs);
945 }; 1144 };
946 1145
947 limit $statgrp $maxreq; 1146 limit $statgrp $maxreq;
948 feed $statgrp sub { 1147 feed $statgrp sub {
949 return unless @$entries; 1148 return unless @$entries;
950 my $entry = shift @$entries; 1149 my $entry = shift @$entries;
951 1150
952 aioreq_pri $pri; 1151 aioreq_pri $pri;
1152 $wd->[1] = "$entry/.";
953 add $statgrp aio_stat "$path/$entry/.", sub { 1153 add $statgrp aio_stat $wd, sub {
954 if ($_[0] < 0) { 1154 if ($_[0] < 0) {
955 push @nondirs, $entry; 1155 push @nondirs, $entry;
956 } else { 1156 } else {
957 # need to check for real directory 1157 # need to check for real directory
958 aioreq_pri $pri; 1158 aioreq_pri $pri;
1159 $wd->[1] = $entry;
959 add $statgrp aio_lstat "$path/$entry", sub { 1160 add $statgrp aio_lstat $wd, sub {
960 if (-d _) { 1161 if (-d _) {
961 push @dirs, $entry; 1162 push @dirs, $entry;
962 1163
963 unless (--$ndirs) { 1164 unless (--$ndirs) {
964 push @nondirs, @$entries; 1165 push @nondirs, @$entries;
965 feed $statgrp; 1166 feed $statgrp;
1167 }
1168 } else {
1169 push @nondirs, $entry;
966 } 1170 }
967 } else {
968 push @nondirs, $entry;
969 } 1171 }
970 } 1172 }
971 } 1173 };
972 }; 1174 };
973 }; 1175 };
974 }; 1176 };
975 }; 1177 };
976 }; 1178 };
977 1179
978 $grp 1180 $grp
979} 1181}
980 1182
981=item aio_rmtree $path, $callback->($status) 1183=item aio_rmtree $pathname, $callback->($status)
982 1184
983Delete a directory tree starting (and including) C<$path>, return the 1185Delete a directory tree starting (and including) C<$path>, return the
984status of the final C<rmdir> only. This is a composite request that 1186status of the final C<rmdir> only. This is a composite request that
985uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1187uses C<aio_scandir> to recurse into and rmdir directories, and unlink
986everything else. 1188everything else.
987 1189
988=cut 1190=cut
989 1191
1028callback with the fdatasync result code. 1230callback with the fdatasync result code.
1029 1231
1030If this call isn't available because your OS lacks it or it couldn't be 1232If this call isn't available because your OS lacks it or it couldn't be
1031detected, it will be emulated by calling C<fsync> instead. 1233detected, it will be emulated by calling C<fsync> instead.
1032 1234
1235=item aio_syncfs $fh, $callback->($status)
1236
1237Asynchronously call the syncfs syscall to sync the filesystem associated
1238to the given filehandle and call the callback with the syncfs result
1239code. If syncfs is not available, calls sync(), but returns C<-1> and sets
1240errno to C<ENOSYS> nevertheless.
1241
1033=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 1242=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1034 1243
1035Sync the data portion of the file specified by C<$offset> and C<$length> 1244Sync the data portion of the file specified by C<$offset> and C<$length>
1036to disk (but NOT the metadata), by calling the Linux-specific 1245to disk (but NOT the metadata), by calling the Linux-specific
1037sync_file_range call. If sync_file_range is not available or it returns 1246sync_file_range call. If sync_file_range is not available or it returns
1040C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, 1249C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1041C<IO::AIO::SYNC_FILE_RANGE_WRITE> and 1250C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1042C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range 1251C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1043manpage for details. 1252manpage for details.
1044 1253
1045=item aio_pathsync $path, $callback->($status) 1254=item aio_pathsync $pathname, $callback->($status)
1046 1255
1047This request tries to open, fsync and close the given path. This is a 1256This request tries to open, fsync and close the given path. This is a
1048composite request intended to sync directories after directory operations 1257composite request intended to sync directories after directory operations
1049(E.g. rename). This might not work on all operating systems or have any 1258(E.g. rename). This might not work on all operating systems or have any
1050specific effect, but usually it makes sure that directory changes get 1259specific effect, but usually it makes sure that directory changes get
1102 1311
1103This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1312This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1104scalars. 1313scalars.
1105 1314
1106It touches (reads or writes) all memory pages in the specified 1315It touches (reads or writes) all memory pages in the specified
1107range inside the scalar. All caveats and parameters are the same 1316range inside the scalar. All caveats and parameters are the same
1108as for C<aio_msync>, above, except for flags, which must be either 1317as for C<aio_msync>, above, except for flags, which must be either
1109C<0> (which reads all pages and ensures they are instantiated) or 1318C<0> (which reads all pages and ensures they are instantiated) or
1110C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and 1319C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1111writing an octet from it, which dirties the page). 1320writing an octet from it, which dirties the page).
1321
1322=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1323
1324This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1325scalars.
1326
1327It reads in all the pages of the underlying storage into memory (if any)
1328and locks them, so they are not getting swapped/paged out or removed.
1329
1330If C<$length> is undefined, then the scalar will be locked till the end.
1331
1332On systems that do not implement C<mlock>, this function returns C<-1>
1333and sets errno to C<ENOSYS>.
1334
1335Note that the corresponding C<munlock> is synchronous and is
1336documented under L<MISCELLANEOUS FUNCTIONS>.
1337
1338Example: open a file, mmap and mlock it - both will be undone when
1339C<$data> gets destroyed.
1340
1341 open my $fh, "<", $path or die "$path: $!";
1342 my $data;
1343 IO::AIO::mmap $data, -s $fh, IO::AIO::PROT_READ, IO::AIO::MAP_SHARED, $fh;
1344 aio_mlock $data; # mlock in background
1345
1346=item aio_mlockall $flags, $callback->($status)
1347
1348Calls the C<mlockall> function with the given C<$flags> (a combination of
1349C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL_FUTURE>).
1350
1351On systems that do not implement C<mlockall>, this function returns C<-1>
1352and sets errno to C<ENOSYS>.
1353
1354Note that the corresponding C<munlockall> is synchronous and is
1355documented under L<MISCELLANEOUS FUNCTIONS>.
1356
1357Example: asynchronously lock all current and future pages into memory.
1358
1359 aio_mlockall IO::AIO::MCL_FUTURE;
1360
1361=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
1362
1363Queries the extents of the given file (by calling the Linux C<FIEMAP>
1364ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
1365the ioctl is not available on your OS, then this request will fail with
1366C<ENOSYS>.
1367
1368C<$start> is the starting offset to query extents for, C<$length> is the
1369size of the range to query - if it is C<undef>, then the whole file will
1370be queried.
1371
1372C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
1373C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
1374exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
1375the data portion.
1376
1377C<$count> is the maximum number of extent records to return. If it is
1378C<undef>, then IO::AIO queries all extents of the range. As a very special
1379case, if it is C<0>, then the callback receives the number of extents
1380instead of the extents themselves (which is unreliable, see below).
1381
1382If an error occurs, the callback receives no arguments. The special
1383C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
1384
1385Otherwise, the callback receives an array reference with extent
1386structures. Each extent structure is an array reference itself, with the
1387following members:
1388
1389 [$logical, $physical, $length, $flags]
1390
1391Flags is any combination of the following flag values (typically either C<0>
1392or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
1393
1394C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
1395C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
1396C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
1397C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
1398C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
1399C<IO::AIO::FIEMAP_EXTENT_SHARED>.
1400
1401At the time of this writing (Linux 3.2), this requets is unreliable unless
1402C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
1403it to return all extents of a range for files with large number of
1404extents. The code works around all these issues if C<$count> is undef.
1112 1405
1113=item aio_group $callback->(...) 1406=item aio_group $callback->(...)
1114 1407
1115This is a very special aio request: Instead of doing something, it is a 1408This is a very special aio request: Instead of doing something, it is a
1116container for other aio requests, which is useful if you want to bundle 1409container for other aio requests, which is useful if you want to bundle
1153like sleep and file handle readable/writable, the overhead this creates is 1446like sleep and file handle readable/writable, the overhead this creates is
1154immense (it blocks a thread for a long time) so do not use this function 1447immense (it blocks a thread for a long time) so do not use this function
1155except to put your application under artificial I/O pressure. 1448except to put your application under artificial I/O pressure.
1156 1449
1157=back 1450=back
1451
1452
1453=head2 IO::AIO::WD - multiple working directories
1454
1455Your process only has one current working directory, which is used by all
1456threads. This makes it hard to use relative paths (some other component
1457could call C<chdir> at any time, and it is hard to control when the path
1458will be used by IO::AIO).
1459
1460One solution for this is to always use absolute paths. This usually works,
1461but can be quite slow (the kernel has to walk the whole path on every
1462access), and can also be a hassle to implement.
1463
1464Newer POSIX systems have a number of functions (openat, fdopendir,
1465futimensat and so on) that make it possible to specify working directories
1466per operation.
1467
1468For portability, and because the clowns who "designed", or shall I write,
1469perpetrated this new interface were obviously half-drunk, this abstraction
1470cannot be perfect, though.
1471
1472IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
1473object. This object stores the canonicalised, absolute version of the
1474path, and on systems that allow it, also a directory file descriptor.
1475
1476Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
1477or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
1478object and a pathname instead (or the IO::AIO::WD object alone, which
1479gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
1480IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
1481to that IO::AIO::WD object.
1482
1483For example, to get a wd object for F</etc> and then stat F<passwd>
1484inside, you would write:
1485
1486 aio_wd "/etc", sub {
1487 my $etcdir = shift;
1488
1489 # although $etcdir can be undef on error, there is generally no reason
1490 # to check for errors here, as aio_stat will fail with ENOENT
1491 # when $etcdir is undef.
1492
1493 aio_stat [$etcdir, "passwd"], sub {
1494 # yay
1495 };
1496 };
1497
1498That C<aio_wd> is a request and not a normal function shows that creating
1499an IO::AIO::WD object is itself a potentially blocking operation, which is
1500why it is done asynchronously.
1501
1502To stat the directory obtained with C<aio_wd> above, one could write
1503either of the following three request calls:
1504
1505 aio_lstat "/etc" , sub { ... # pathname as normal string
1506 aio_lstat [$wd, "."], sub { ... # "." relative to $wd (i.e. $wd itself)
1507 aio_lstat $wd , sub { ... # shorthand for the previous
1508
1509As with normal pathnames, IO::AIO keeps a copy of the working directory
1510object and the pathname string, so you could write the following without
1511causing any issues due to C<$path> getting reused:
1512
1513 my $path = [$wd, undef];
1514
1515 for my $name (qw(abc def ghi)) {
1516 $path->[1] = $name;
1517 aio_stat $path, sub {
1518 # ...
1519 };
1520 }
1521
1522There are some caveats: when directories get renamed (or deleted), the
1523pathname string doesn't change, so will point to the new directory (or
1524nowhere at all), while the directory fd, if available on the system,
1525will still point to the original directory. Most functions accepting a
1526pathname will use the directory fd on newer systems, and the string on
1527older systems. Some functions (such as realpath) will always rely on the
1528string form of the pathname.
1529
1530So this functionality is mainly useful to get some protection against
1531C<chdir>, to easily get an absolute path out of a relative path for future
1532reference, and to speed up doing many operations in the same directory
1533(e.g. when stat'ing all files in a directory).
1534
1535The following functions implement this working directory abstraction:
1536
1537=over 4
1538
1539=item aio_wd $pathname, $callback->($wd)
1540
1541Asynchonously canonicalise the given pathname and convert it to an
1542IO::AIO::WD object representing it. If possible and supported on the
1543system, also open a directory fd to speed up pathname resolution relative
1544to this working directory.
1545
1546If something goes wrong, then C<undef> is passwd to the callback instead
1547of a working directory object and C<$!> is set appropriately. Since
1548passing C<undef> as working directory component of a pathname fails the
1549request with C<ENOENT>, there is often no need for error checking in the
1550C<aio_wd> callback, as future requests using the value will fail in the
1551expected way.
1552
1553If this call isn't available because your OS lacks it or it couldn't be
1554detected, it will be emulated by calling C<fsync> instead.
1555
1556=item IO::AIO::CWD
1557
1558This is a compiletime constant (object) that represents the process
1559current working directory.
1560
1561Specifying this object as working directory object for a pathname is as if
1562the pathname would be specified directly, without a directory object. For
1563example, these calls are functionally identical:
1564
1565 aio_stat "somefile", sub { ... };
1566 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1567
1568=back
1569
1570To recover the path associated with an IO::AIO::WD object, you can use
1571C<aio_realpath>:
1572
1573 aio_realpath $wd, sub {
1574 warn "path is $_[0]\n";
1575 };
1576
1158 1577
1159=head2 IO::AIO::REQ CLASS 1578=head2 IO::AIO::REQ CLASS
1160 1579
1161All non-aggregate C<aio_*> functions return an object of this class when 1580All non-aggregate C<aio_*> functions return an object of this class when
1162called in non-void context. 1581called in non-void context.
1280 1699
1281Sets a feeder/generator on this group: every group can have an attached 1700Sets a feeder/generator on this group: every group can have an attached
1282generator that generates requests if idle. The idea behind this is that, 1701generator that generates requests if idle. The idea behind this is that,
1283although you could just queue as many requests as you want in a group, 1702although you could just queue as many requests as you want in a group,
1284this might starve other requests for a potentially long time. For example, 1703this might starve other requests for a potentially long time. For example,
1285C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1704C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1286delaying any later requests for a long time. 1705requests, delaying any later requests for a long time.
1287 1706
1288To avoid this, and allow incremental generation of requests, you can 1707To avoid this, and allow incremental generation of requests, you can
1289instead a group and set a feeder on it that generates those requests. The 1708instead a group and set a feeder on it that generates those requests. The
1290feed callback will be called whenever there are few enough (see C<limit>, 1709feed callback will be called whenever there are few enough (see C<limit>,
1291below) requests active in the group itself and is expected to queue more 1710below) requests active in the group itself and is expected to queue more
1340 1759
1341See C<poll_cb> for an example. 1760See C<poll_cb> for an example.
1342 1761
1343=item IO::AIO::poll_cb 1762=item IO::AIO::poll_cb
1344 1763
1345Process some outstanding events on the result pipe. You have to call this 1764Process some requests that have reached the result phase (i.e. they have
1346regularly. Returns C<0> if all events could be processed, or C<-1> if it 1765been executed but the results are not yet reported). You have to call
1347returned earlier for whatever reason. Returns immediately when no events 1766this "regularly" to finish outstanding requests.
1348are outstanding. The amount of events processed depends on the settings of
1349C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1350 1767
1768Returns C<0> if all events could be processed (or there were no
1769events to process), or C<-1> if it returned earlier for whatever
1770reason. Returns immediately when no events are outstanding. The amount
1771of events processed depends on the settings of C<IO::AIO::max_poll_req>,
1772C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
1773
1351If not all requests were processed for whatever reason, the filehandle 1774If not all requests were processed for whatever reason, the poll file
1352will still be ready when C<poll_cb> returns, so normally you don't have to 1775descriptor will still be ready when C<poll_cb> returns, so normally you
1353do anything special to have it called later. 1776don't have to do anything special to have it called later.
1777
1778Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
1779ready, it can be beneficial to call this function from loops which submit
1780a lot of requests, to make sure the results get processed when they become
1781available and not just when the loop is finished and the event loop takes
1782over again. This function returns very fast when there are no outstanding
1783requests.
1354 1784
1355Example: Install an Event watcher that automatically calls 1785Example: Install an Event watcher that automatically calls
1356IO::AIO::poll_cb with high priority (more examples can be found in the 1786IO::AIO::poll_cb with high priority (more examples can be found in the
1357SYNOPSIS section, at the top of this document): 1787SYNOPSIS section, at the top of this document):
1358 1788
1360 poll => 'r', async => 1, 1790 poll => 'r', async => 1,
1361 cb => \&IO::AIO::poll_cb); 1791 cb => \&IO::AIO::poll_cb);
1362 1792
1363=item IO::AIO::poll_wait 1793=item IO::AIO::poll_wait
1364 1794
1365If there are any outstanding requests and none of them in the result 1795Wait until either at least one request is in the result phase or no
1366phase, wait till the result filehandle becomes ready for reading (simply 1796requests are outstanding anymore.
1367does a C<select> on the filehandle. This is useful if you want to 1797
1368synchronously wait for some requests to finish). 1798This is useful if you want to synchronously wait for some requests to
1799become ready, without actually handling them.
1369 1800
1370See C<nreqs> for an example. 1801See C<nreqs> for an example.
1371 1802
1372=item IO::AIO::poll 1803=item IO::AIO::poll
1373 1804
1460 1891
1461Under normal circumstances you don't need to call this function. 1892Under normal circumstances you don't need to call this function.
1462 1893
1463=item IO::AIO::max_idle $nthreads 1894=item IO::AIO::max_idle $nthreads
1464 1895
1465Limit the number of threads (default: 4) that are allowed to idle (i.e., 1896Limit the number of threads (default: 4) that are allowed to idle
1466threads that did not get a request to process within 10 seconds). That 1897(i.e., threads that did not get a request to process within the idle
1467means if a thread becomes idle while C<$nthreads> other threads are also 1898timeout (default: 10 seconds). That means if a thread becomes idle while
1468idle, it will free its resources and exit. 1899C<$nthreads> other threads are also idle, it will free its resources and
1900exit.
1469 1901
1470This is useful when you allow a large number of threads (e.g. 100 or 1000) 1902This is useful when you allow a large number of threads (e.g. 100 or 1000)
1471to allow for extremely high load situations, but want to free resources 1903to allow for extremely high load situations, but want to free resources
1472under normal circumstances (1000 threads can easily consume 30MB of RAM). 1904under normal circumstances (1000 threads can easily consume 30MB of RAM).
1473 1905
1474The default is probably ok in most situations, especially if thread 1906The default is probably ok in most situations, especially if thread
1475creation is fast. If thread creation is very slow on your system you might 1907creation is fast. If thread creation is very slow on your system you might
1476want to use larger values. 1908want to use larger values.
1477 1909
1910=item IO::AIO::idle_timeout $seconds
1911
1912Sets the minimum idle timeout (default 10) after which worker threads are
1913allowed to exit. SEe C<IO::AIO::max_idle>.
1914
1478=item IO::AIO::max_outstanding $maxreqs 1915=item IO::AIO::max_outstanding $maxreqs
1916
1917Sets the maximum number of outstanding requests to C<$nreqs>. If
1918you do queue up more than this number of requests, the next call to
1919C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
1920C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
1921longer exceeded.
1922
1923In other words, this setting does not enforce a queue limit, but can be
1924used to make poll functions block if the limit is exceeded.
1479 1925
1480This is a very bad function to use in interactive programs because it 1926This is a very bad function to use in interactive programs because it
1481blocks, and a bad way to reduce concurrency because it is inexact: Better 1927blocks, and a bad way to reduce concurrency because it is inexact: Better
1482use an C<aio_group> together with a feed callback. 1928use an C<aio_group> together with a feed callback.
1483 1929
1484Sets the maximum number of outstanding requests to C<$nreqs>. If you 1930It's main use is in scripts without an event loop - when you want to stat
1485do queue up more than this number of requests, the next call to the 1931a lot of files, you can write somehting like this:
1486C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1487function will block until the limit is no longer exceeded.
1488 1932
1489The default value is very large, so there is no practical limit on the 1933 IO::AIO::max_outstanding 32;
1490number of outstanding requests.
1491 1934
1492You can still queue as many requests as you want. Therefore, 1935 for my $path (...) {
1493C<max_outstanding> is mainly useful in simple scripts (with low values) or 1936 aio_stat $path , ...;
1494as a stop gap to shield against fatal memory overflow (with large values). 1937 IO::AIO::poll_cb;
1938 }
1939
1940 IO::AIO::flush;
1941
1942The call to C<poll_cb> inside the loop will normally return instantly, but
1943as soon as more thna C<32> reqeusts are in-flight, it will block until
1944some requests have been handled. This keeps the loop from pushing a large
1945number of C<aio_stat> requests onto the queue.
1946
1947The default value for C<max_outstanding> is very large, so there is no
1948practical limit on the number of outstanding requests.
1495 1949
1496=back 1950=back
1497 1951
1498=head3 STATISTICAL INFORMATION 1952=head3 STATISTICAL INFORMATION
1499 1953
1537 1991
1538Returns the number of bytes copied, or C<-1> on error. 1992Returns the number of bytes copied, or C<-1> on error.
1539 1993
1540=item IO::AIO::fadvise $fh, $offset, $len, $advice 1994=item IO::AIO::fadvise $fh, $offset, $len, $advice
1541 1995
1542Simply calls the C<posix_fadvise> function (see it's 1996Simply calls the C<posix_fadvise> function (see its
1543manpage for details). The following advice constants are 1997manpage for details). The following advice constants are
1544avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, 1998available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1545C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, 1999C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1546C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. 2000C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1547 2001
1548On systems that do not implement C<posix_fadvise>, this function returns 2002On systems that do not implement C<posix_fadvise>, this function returns
1549ENOSYS, otherwise the return value of C<posix_fadvise>. 2003ENOSYS, otherwise the return value of C<posix_fadvise>.
1550 2004
2005=item IO::AIO::madvise $scalar, $offset, $len, $advice
2006
2007Simply calls the C<posix_madvise> function (see its
2008manpage for details). The following advice constants are
2009available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2010C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
2011
2012On systems that do not implement C<posix_madvise>, this function returns
2013ENOSYS, otherwise the return value of C<posix_madvise>.
2014
2015=item IO::AIO::mprotect $scalar, $offset, $len, $protect
2016
2017Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2018$scalar (see its manpage for details). The following protect
2019constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2020C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2021
2022On systems that do not implement C<mprotect>, this function returns
2023ENOSYS, otherwise the return value of C<mprotect>.
2024
1551=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2025=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1552 2026
1553Memory-maps a file (or anonymous memory range) and attaches it to the 2027Memory-maps a file (or anonymous memory range) and attaches it to the
1554given C<$scalar>, which will act like a string scalar. 2028given C<$scalar>, which will act like a string scalar. Returns true on
2029success, and false otherwise.
1555 2030
1556The only operations allowed on the scalar are C<substr>/C<vec> that don't 2031The only operations allowed on the scalar are C<substr>/C<vec> that don't
1557change the string length, and most read-only operations such as copying it 2032change the string length, and most read-only operations such as copying it
1558or searching it with regexes and so on. 2033or searching it with regexes and so on.
1559 2034
1600 2075
1601=item IO::AIO::munmap $scalar 2076=item IO::AIO::munmap $scalar
1602 2077
1603Removes a previous mmap and undefines the C<$scalar>. 2078Removes a previous mmap and undefines the C<$scalar>.
1604 2079
1605=item IO::AIO::mlockall $flags 2080=item IO::AIO::munlock $scalar, $offset = 0, $length = undef
1606 2081
1607Calls the C<mlockall> function with the given C<$flags> (a combination of 2082Calls the C<munlock> function, undoing the effects of a previous
1608C<IO::AIO::MCL_CURRENT> and C<IO::AIO::MCL__FUTURE>). 2083C<aio_mlock> call (see its description for details).
1609
1610On systems that do not implement C<mlockall>, this function returns
1611ENOSYS, otherwise the return value of C<mlockall>.
1612 2084
1613=item IO::AIO::munlockall 2085=item IO::AIO::munlockall
1614 2086
1615Calls the C<munlockall> function. 2087Calls the C<munlockall> function.
1616 2088
1617On systems that do not implement C<munlockall>, this function returns 2089On systems that do not implement C<munlockall>, this function returns
1618ENOSYS, otherwise the return value of C<munlockall>. 2090ENOSYS, otherwise the return value of C<munlockall>.
2091
2092=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2093
2094Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2095C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2096should be the file offset.
2097
2098C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2099silently corrupt the data in this case.
2100
2101The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2102C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2103C<IO::AIO::SPLICE_F_GIFT>.
2104
2105See the C<splice(2)> manpage for details.
2106
2107=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2108
2109Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
2110description for C<IO::AIO::splice> above for details.
1619 2111
1620=back 2112=back
1621 2113
1622=cut 2114=cut
1623 2115
1658 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => 2150 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1659 \&IO::AIO::poll_cb); 2151 \&IO::AIO::poll_cb);
1660 2152
1661=head2 FORK BEHAVIOUR 2153=head2 FORK BEHAVIOUR
1662 2154
1663This module should do "the right thing" when the process using it forks: 2155Usage of pthreads in a program changes the semantics of fork
2156considerably. Specifically, only async-safe functions can be called after
2157fork. Perl doesn't know about this, so in general, you cannot call fork
2158with defined behaviour in perl if pthreads are involved. IO::AIO uses
2159pthreads, so this applies, but many other extensions and (for inexplicable
2160reasons) perl itself often is linked against pthreads, so this limitation
2161applies to quite a lot of perls.
1664 2162
1665Before the fork, IO::AIO enters a quiescent state where no requests 2163This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1666can be added in other threads and no results will be processed. After 2164only works in the process that loaded it. Forking is fully supported, but
1667the fork the parent simply leaves the quiescent state and continues 2165using IO::AIO in the child is not.
1668request/result processing, while the child frees the request/result queue
1669(so that the requests started before the fork will only be handled in the
1670parent). Threads will be started on demand until the limit set in the
1671parent process has been reached again.
1672 2166
1673In short: the parent will, after a short pause, continue as if fork had 2167You might get around by not I<using> IO::AIO before (or after)
1674not been called, while the child will act as if IO::AIO has not been used 2168forking. You could also try to call the L<IO::AIO::reinit> function in the
1675yet. 2169child:
2170
2171=over 4
2172
2173=item IO::AIO::reinit
2174
2175Abandons all current requests and I/O threads and simply reinitialises all
2176data structures. This is not an operation supported by any standards, but
2177happens to work on GNU/Linux and some newer BSD systems.
2178
2179The only reasonable use for this function is to call it after forking, if
2180C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
2181the process will result in undefined behaviour. Calling it at any time
2182will also result in any undefined (by POSIX) behaviour.
2183
2184=back
1676 2185
1677=head2 MEMORY USAGE 2186=head2 MEMORY USAGE
1678 2187
1679Per-request usage: 2188Per-request usage:
1680 2189

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