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Revision 1.195 by root, Fri May 27 19:56:31 2011 UTC vs.
Revision 1.237 by root, Thu Oct 11 03:20:52 2012 UTC

… …
168use common::sense; 168use common::sense;
169 169
170use base 'Exporter'; 170use base 'Exporter';
171 171
172BEGIN { 172BEGIN {
173 our $VERSION = '3.9'; 173 our $VERSION = '4.17';
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_mlock aio_mlockall 183 aio_msync aio_mtouch aio_mlock aio_mlockall
183 aio_statvfs); 184 aio_statvfs
185 aio_wd);
184 186
185 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice)); 187 our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));
186 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush 188 our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
187 min_parallel max_parallel max_idle idle_timeout 189 min_parallel max_parallel max_idle idle_timeout
188 nreqs nready npending nthreads 190 nreqs nready npending nthreads
… …
200 202
201=head1 FUNCTIONS 203=head1 FUNCTIONS
202 204
203=head2 QUICK OVERVIEW 205=head2 QUICK OVERVIEW
204 206
205This section simply lists the prototypes of the most important functions 207This section simply lists the prototypes most of the functions for
206for quick reference. See the following sections for function-by-function 208quick reference. See the following sections for function-by-function
207documentation. 209documentation.
208 210
211 aio_wd $pathname, $callback->($wd)
209 aio_open $pathname, $flags, $mode, $callback->($fh) 212 aio_open $pathname, $flags, $mode, $callback->($fh)
210 aio_close $fh, $callback->($status) 213 aio_close $fh, $callback->($status)
214 aio_seek $fh,$offset,$whence, $callback->($offs)
211 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 215 aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
212 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 216 aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
213 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval) 217 aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
214 aio_readahead $fh,$offset,$length, $callback->($retval) 218 aio_readahead $fh,$offset,$length, $callback->($retval)
215 aio_stat $fh_or_path, $callback->($status) 219 aio_stat $fh_or_path, $callback->($status)
216 aio_lstat $fh, $callback->($status) 220 aio_lstat $fh, $callback->($status)
217 aio_statvfs $fh_or_path, $callback->($statvfs) 221 aio_statvfs $fh_or_path, $callback->($statvfs)
218 aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 222 aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
219 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)
220 aio_truncate $fh_or_path, $offset, $callback->($status) 225 aio_truncate $fh_or_path, $offset, $callback->($status)
221 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)
222 aio_unlink $pathname, $callback->($status) 228 aio_unlink $pathname, $callback->($status)
223 aio_mknod $path, $mode, $dev, $callback->($status) 229 aio_mknod $pathname, $mode, $dev, $callback->($status)
224 aio_link $srcpath, $dstpath, $callback->($status) 230 aio_link $srcpath, $dstpath, $callback->($status)
225 aio_symlink $srcpath, $dstpath, $callback->($status) 231 aio_symlink $srcpath, $dstpath, $callback->($status)
226 aio_readlink $path, $callback->($link) 232 aio_readlink $pathname, $callback->($link)
233 aio_realpath $pathname, $callback->($link)
227 aio_rename $srcpath, $dstpath, $callback->($status) 234 aio_rename $srcpath, $dstpath, $callback->($status)
228 aio_mkdir $pathname, $mode, $callback->($status) 235 aio_mkdir $pathname, $mode, $callback->($status)
229 aio_rmdir $pathname, $callback->($status) 236 aio_rmdir $pathname, $callback->($status)
230 aio_readdir $pathname, $callback->($entries) 237 aio_readdir $pathname, $callback->($entries)
231 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 238 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
232 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 239 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
233 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)
234 aio_load $path, $data, $callback->($status) 242 aio_load $pathname, $data, $callback->($status)
235 aio_copy $srcpath, $dstpath, $callback->($status) 243 aio_copy $srcpath, $dstpath, $callback->($status)
236 aio_move $srcpath, $dstpath, $callback->($status) 244 aio_move $srcpath, $dstpath, $callback->($status)
237 aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
238 aio_rmtree $path, $callback->($status) 245 aio_rmtree $pathname, $callback->($status)
239 aio_sync $callback->($status) 246 aio_sync $callback->($status)
247 aio_syncfs $fh, $callback->($status)
240 aio_fsync $fh, $callback->($status) 248 aio_fsync $fh, $callback->($status)
241 aio_fdatasync $fh, $callback->($status) 249 aio_fdatasync $fh, $callback->($status)
242 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 250 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
243 aio_pathsync $path, $callback->($status) 251 aio_pathsync $pathname, $callback->($status)
244 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 252 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
245 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 253 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
246 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 254 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
247 aio_mlockall $flags, $callback->($status) 255 aio_mlockall $flags, $callback->($status)
248 aio_group $callback->(...) 256 aio_group $callback->(...)
… …
266 IO::AIO::nready 274 IO::AIO::nready
267 IO::AIO::npending 275 IO::AIO::npending
268 276
269 IO::AIO::sendfile $ofh, $ifh, $offset, $count 277 IO::AIO::sendfile $ofh, $ifh, $offset, $count
270 IO::AIO::fadvise $fh, $offset, $len, $advice 278 IO::AIO::fadvise $fh, $offset, $len, $advice
279 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280 IO::AIO::munmap $scalar
271 IO::AIO::madvise $scalar, $offset, $length, $advice 281 IO::AIO::madvise $scalar, $offset, $length, $advice
272 IO::AIO::mprotect $scalar, $offset, $length, $protect 282 IO::AIO::mprotect $scalar, $offset, $length, $protect
273 IO::AIO::munlock $scalar, $offset = 0, $length = undef 283 IO::AIO::munlock $scalar, $offset = 0, $length = undef
274 IO::AIO::munlockall 284 IO::AIO::munlockall
275 285
276=head2 AIO REQUEST FUNCTIONS 286=head2 API NOTES
277 287
278All the C<aio_*> calls are more or less thin wrappers around the syscall 288All the C<aio_*> calls are more or less thin wrappers around the syscall
279with the same name (sans C<aio_>). The arguments are similar or identical, 289with the same name (sans C<aio_>). The arguments are similar or identical,
280and they all accept an additional (and optional) C<$callback> argument 290and they all accept an additional (and optional) C<$callback> argument
281which must be a code reference. This code reference will get called with 291which must be a code reference. This code reference will be called after
282the syscall return code (e.g. most syscalls return C<-1> on error, unlike 292the syscall has been executed in an asynchronous fashion. The results
283perl, which usually delivers "false") as its sole argument after the given 293of the request will be passed as arguments to the callback (and, if an
284syscall has been executed asynchronously. 294error occured, in C<$!>) - 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>.
285 300
286All functions expecting a filehandle keep a copy of the filehandle 301All functions expecting a filehandle keep a copy of the filehandle
287internally until the request has finished. 302internally until the request has finished.
288 303
289All 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
290further manipulation of those requests while they are in-flight. 305further manipulation of those requests while they are in-flight.
291 306
292The pathnames you pass to these routines I<must> be absolute and 307The pathnames you pass to these routines I<should> be absolute. The
293encoded 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
294request is being executed, the current working directory could have 309current working directory could have changed. Alternatively, you can
295changed. Alternatively, you can make sure that you never change the 310make sure that you never change the current working directory anywhere
296current working directory anywhere in the program and then use relative 311in the program and then use relative paths. You can also take advantage
297paths. 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.
298 315
299To 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
300in filenames you got from outside (command line, readdir etc.) without 317in filenames you got from outside (command line, readdir etc.) without
301tinkering, 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
302your pathnames to the locale (or other) encoding in effect in the user 319module and encode your pathnames to the locale (or other) encoding in
303environment, d) use Glib::filename_from_unicode on unicode filenames or e) 320effect in the user environment, d) use Glib::filename_from_unicode on
304use 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.
305 323
306This 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
307handles correctly whether it is set or not. 325handles correctly whether it is set or not.
326
327=head2 AIO REQUEST FUNCTIONS
308 328
309=over 4 329=over 4
310 330
311=item $prev_pri = aioreq_pri [$pri] 331=item $prev_pri = aioreq_pri [$pri]
312 332
… …
342 362
343 363
344=item aio_open $pathname, $flags, $mode, $callback->($fh) 364=item aio_open $pathname, $flags, $mode, $callback->($fh)
345 365
346Asynchronously 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
347created filehandle for the file. 367created filehandle for the file (or C<undef> in case of an error).
348 368
349The 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,
350for an explanation. 370for an explanation.
351 371
352The 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
… …
395Or 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
396free for reuse until the perl filehandle is closed. 416free for reuse until the perl filehandle is closed.
397 417
398=cut 418=cut
399 419
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".
439
400=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
401 441
402=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
403 443
404Reads or writes C<$length> bytes from or to the specified C<$fh> and 444Reads or writes C<$length> bytes from or to the specified C<$fh> and
… …
436 476
437Tries 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
438reading 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
439file 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
440than 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
441other. 481other. The same C<$in_fh> works fine though, as this function does not
482move or use the file offset of C<$in_fh>.
442 483
443Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than 484Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
444are written, and there is no way to find out how many bytes have been read 485are written, and there is no way to find out how many more bytes have been
445from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of 486read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
446bytes written to C<$out_fh>. Only if the result value equals C<$length> 487number of bytes written to C<$out_fh>. Only if the result value equals
447one can assume that C<$length> bytes have been read. 488C<$length> one can assume that C<$length> bytes have been read.
448 489
449Unlike with other C<aio_> functions, it makes a lot of sense to use 490Unlike with other C<aio_> functions, it makes a lot of sense to use
450C<aio_sendfile> on non-blocking sockets, as long as one end (typically 491C<aio_sendfile> on non-blocking sockets, as long as one end (typically
451the C<$in_fh>) is a file - the file I/O will then be asynchronous, while 492the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
452the socket I/O will be non-blocking. Note, however, that you can run into 493the socket I/O will be non-blocking. Note, however, that you can run
453a trap where C<aio_sendfile> reads some data with readahead, then fails 494into a trap where C<aio_sendfile> reads some data with readahead, then
454to write all data, and when the socket is ready the next time, the data 495fails to write all data, and when the socket is ready the next time, the
455in the cache is already lost, forcing C<aio_sendfile> to again hit the 496data in the cache is already lost, forcing C<aio_sendfile> to again hit
456disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage 497the disk. Explicit C<aio_read> + C<aio_write> let's you better control
457much better. 498resource usage.
458 499
459This 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
460zero-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
461socket, and C<$in_fh> should refer to an mmap'able file. 502a socket, and C<$in_fh> should refer to an mmap'able file.
462 503
463If 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>,
464C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>, 505C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
465it 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
466filehandle regardless of the limitations of the operating system. 507type of filehandle regardless of the limitations of the operating system.
508
509As native sendfile syscalls (as practically any non-POSIX interface hacked
510together in a hurry to improve benchmark numbers) tend to be rather buggy
511on many systems, this implementation tries to work around some known bugs
512in Linux and FreeBSD kernels (probably others, too), but that might fail,
513so you really really should check the return value of C<aio_sendfile> -
514fewre bytes than expected might have been transferred.
467 515
468 516
469=item aio_readahead $fh,$offset,$length, $callback->($retval) 517=item aio_readahead $fh,$offset,$length, $callback->($retval)
470 518
471C<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
… …
555 namemax => 255, 603 namemax => 255,
556 frsize => 1024, 604 frsize => 1024,
557 fsid => 1810 605 fsid => 1810
558 } 606 }
559 607
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
560 689
561=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status) 690=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
562 691
563Works 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
564and $mtime being undef). Fractional times are supported if the underlying 693and $mtime being undef). Fractional times are supported if the underlying
… …
592=item aio_truncate $fh_or_path, $offset, $callback->($status) 721=item aio_truncate $fh_or_path, $offset, $callback->($status)
593 722
594Works like truncate(2) or ftruncate(2). 723Works like truncate(2) or ftruncate(2).
595 724
596 725
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
597=item aio_chmod $fh_or_path, $mode, $callback->($status) 742=item aio_chmod $fh_or_path, $mode, $callback->($status)
598 743
599Works like perl's C<chmod> function. 744Works like perl's C<chmod> function.
600 745
601 746
… …
603 748
604Asynchronously unlink (delete) a file and call the callback with the 749Asynchronously unlink (delete) a file and call the callback with the
605result code. 750result code.
606 751
607 752
608=item aio_mknod $path, $mode, $dev, $callback->($status) 753=item aio_mknod $pathname, $mode, $dev, $callback->($status)
609 754
610[EXPERIMENTAL] 755[EXPERIMENTAL]
611 756
612Asynchronously create a device node (or fifo). See mknod(2). 757Asynchronously create a device node (or fifo). See mknod(2).
613 758
614The only (POSIX-) portable way of calling this function is: 759The only (POSIX-) portable way of calling this function is:
615 760
616 aio_mknod $path, IO::AIO::S_IFIFO | $mode, 0, sub { ... 761 aio_mknod $pathname, IO::AIO::S_IFIFO | $mode, 0, sub { ...
617 762
618See C<aio_stat> for info about some potentially helpful extra constants 763See C<aio_stat> for info about some potentially helpful extra constants
619and functions. 764and functions.
620 765
621=item aio_link $srcpath, $dstpath, $callback->($status) 766=item aio_link $srcpath, $dstpath, $callback->($status)
… …
628 773
629Asynchronously 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
630the path C<$dstpath> and call the callback with the result code. 775the path C<$dstpath> and call the callback with the result code.
631 776
632 777
633=item aio_readlink $path, $callback->($link) 778=item aio_readlink $pathname, $callback->($link)
634 779
635Asynchronously read the symlink specified by C<$path> and pass it to 780Asynchronously read the symlink specified by C<$path> and pass it to
636the 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
637callback. 782callback.
638 783
639 784
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
640=item aio_rename $srcpath, $dstpath, $callback->($status) 795=item aio_rename $srcpath, $dstpath, $callback->($status)
641 796
642Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 797Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
643rename(2) and call the callback with the result code. 798rename(2) and call the callback with the result code.
644 799
… …
666array-ref with the filenames. 821array-ref with the filenames.
667 822
668 823
669=item aio_readdirx $pathname, $flags, $callback->($entries, $flags) 824=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
670 825
671Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune 826Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
672behaviour and output format. In case of an error, C<$entries> will be 827tune behaviour and output format. In case of an error, C<$entries> will be
673C<undef>. 828C<undef>.
674 829
675The flags are a combination of the following constants, ORed together (the 830The flags are a combination of the following constants, ORed together (the
676flags will also be passed to the callback, possibly modified): 831flags will also be passed to the callback, possibly modified):
677 832
… …
724 879
725=item IO::AIO::READDIR_FOUND_UNKNOWN 880=item IO::AIO::READDIR_FOUND_UNKNOWN
726 881
727This flag should not be set when calling C<aio_readdirx>. Instead, it 882This flag should not be set when calling C<aio_readdirx>. Instead, it
728is being set by C<aio_readdirx>, when any of the C<$type>'s found were 883is being set by C<aio_readdirx>, when any of the C<$type>'s found were
729C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all 884C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
730C<$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.
731 886
732=back 887=back
733 888
734 889
735=item aio_load $path, $data, $callback->($status) 890=item aio_load $pathname, $data, $callback->($status)
736 891
737This 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
738memory. Status is the same as with aio_read. 893memory. Status is the same as with aio_read.
739 894
740=cut 895=cut
… …
862 if ($_[0] && $! == EXDEV) { 1017 if ($_[0] && $! == EXDEV) {
863 aioreq_pri $pri; 1018 aioreq_pri $pri;
864 add $grp aio_copy $src, $dst, sub { 1019 add $grp aio_copy $src, $dst, sub {
865 $grp->result ($_[0]); 1020 $grp->result ($_[0]);
866 1021
867 if (!$_[0]) { 1022 unless ($_[0]) {
868 aioreq_pri $pri; 1023 aioreq_pri $pri;
869 add $grp aio_unlink $src; 1024 add $grp aio_unlink $src;
870 } 1025 }
871 }; 1026 };
872 } else { 1027 } else {
… …
875 }; 1030 };
876 1031
877 $grp 1032 $grp
878} 1033}
879 1034
880=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs) 1035=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
881 1036
882Scans a directory (similar to C<aio_readdir>) but additionally tries to 1037Scans a directory (similar to C<aio_readdir>) but additionally tries to
883efficiently separate the entries of directory C<$path> into two sets of 1038efficiently separate the entries of directory C<$path> into two sets of
884names, directories you can recurse into (directories), and ones you cannot 1039names, directories you can recurse into (directories), and ones you cannot
885recurse into (everything else, including symlinks to directories). 1040recurse into (everything else, including symlinks to directories).
… …
916Then entries will be sorted into likely directories a non-initial dot 1071Then entries will be sorted into likely directories a non-initial dot
917currently) and likely non-directories (see C<aio_readdirx>). Then every 1072currently) and likely non-directories (see C<aio_readdirx>). Then every
918entry 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,
919in 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
920entry 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
921seperately). This is often faster than stat'ing the entry itself because 1076separately). This is often faster than stat'ing the entry itself because
922filesystems might detect the type of the entry without reading the inode 1077filesystems might detect the type of the entry without reading the inode
923data (e.g. ext2fs filetype feature), even on systems that cannot return 1078data (e.g. ext2fs filetype feature), even on systems that cannot return
924the filetype information on readdir. 1079the filetype information on readdir.
925 1080
926If 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
… …
942 1097
943 my $grp = aio_group $cb; 1098 my $grp = aio_group $cb;
944 1099
945 $maxreq = 4 if $maxreq <= 0; 1100 $maxreq = 4 if $maxreq <= 0;
946 1101
947 # stat once 1102 # get a wd object
948 aioreq_pri $pri; 1103 aioreq_pri $pri;
949 add $grp aio_stat $path, sub { 1104 add $grp aio_wd $path, sub {
1105 $_[0]
950 return $grp->result () if $_[0]; 1106 or return $grp->result ();
951 my $now = time;
952 my $hash1 = join ":", (stat _)[0,1,3,7,9];
953 1107
954 # read the directory entries 1108 my $wd = [shift, "."];
1109
1110 # stat once
955 aioreq_pri $pri; 1111 aioreq_pri $pri;
956 add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub { 1112 add $grp aio_stat $wd, sub {
957 my $entries = shift
958 or return $grp->result (); 1113 return $grp->result () if $_[0];
1114 my $now = time;
1115 my $hash1 = join ":", (stat _)[0,1,3,7,9];
959 1116
960 # stat the dir another time 1117 # read the directory entries
961 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;
962 add $grp aio_stat $path, sub { 1125 add $grp aio_stat $wd, sub {
963 my $hash2 = join ":", (stat _)[0,1,3,7,9]; 1126 my $hash2 = join ":", (stat _)[0,1,3,7,9];
964 1127
965 my $ndirs; 1128 my $ndirs;
966 1129
967 # take the slow route if anything looks fishy 1130 # take the slow route if anything looks fishy
968 if ($hash1 ne $hash2 or (stat _)[9] == $now) { 1131 if ($hash1 ne $hash2 or (stat _)[9] == $now) {
969 $ndirs = -1; 1132 $ndirs = -1;
970 } else { 1133 } else {
971 # if nlink == 2, we are finished 1134 # if nlink == 2, we are finished
972 # for non-posix-fs's, we rely on nlink < 2 1135 # for non-posix-fs's, we rely on nlink < 2
973 $ndirs = (stat _)[3] - 2 1136 $ndirs = (stat _)[3] - 2
974 or return $grp->result ([], $entries); 1137 or return $grp->result ([], $entries);
975 } 1138 }
976 1139
977 my (@dirs, @nondirs); 1140 my (@dirs, @nondirs);
978 1141
979 my $statgrp = add $grp aio_group sub { 1142 my $statgrp = add $grp aio_group sub {
980 $grp->result (\@dirs, \@nondirs); 1143 $grp->result (\@dirs, \@nondirs);
981 }; 1144 };
982 1145
983 limit $statgrp $maxreq; 1146 limit $statgrp $maxreq;
984 feed $statgrp sub { 1147 feed $statgrp sub {
985 return unless @$entries; 1148 return unless @$entries;
986 my $entry = shift @$entries; 1149 my $entry = shift @$entries;
987 1150
988 aioreq_pri $pri; 1151 aioreq_pri $pri;
1152 $wd->[1] = "$entry/.";
989 add $statgrp aio_stat "$path/$entry/.", sub { 1153 add $statgrp aio_stat $wd, sub {
990 if ($_[0] < 0) { 1154 if ($_[0] < 0) {
991 push @nondirs, $entry; 1155 push @nondirs, $entry;
992 } else { 1156 } else {
993 # need to check for real directory 1157 # need to check for real directory
994 aioreq_pri $pri; 1158 aioreq_pri $pri;
1159 $wd->[1] = $entry;
995 add $statgrp aio_lstat "$path/$entry", sub { 1160 add $statgrp aio_lstat $wd, sub {
996 if (-d _) { 1161 if (-d _) {
997 push @dirs, $entry; 1162 push @dirs, $entry;
998 1163
999 unless (--$ndirs) { 1164 unless (--$ndirs) {
1000 push @nondirs, @$entries; 1165 push @nondirs, @$entries;
1001 feed $statgrp; 1166 feed $statgrp;
1167 }
1168 } else {
1169 push @nondirs, $entry;
1002 } 1170 }
1003 } else {
1004 push @nondirs, $entry;
1005 } 1171 }
1006 } 1172 }
1007 } 1173 };
1008 }; 1174 };
1009 }; 1175 };
1010 }; 1176 };
1011 }; 1177 };
1012 }; 1178 };
1013 1179
1014 $grp 1180 $grp
1015} 1181}
1016 1182
1017=item aio_rmtree $path, $callback->($status) 1183=item aio_rmtree $pathname, $callback->($status)
1018 1184
1019Delete a directory tree starting (and including) C<$path>, return the 1185Delete a directory tree starting (and including) C<$path>, return the
1020status 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
1021uses C<aio_scandir> to recurse into and rmdir directories, and unlink 1187uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1022everything else. 1188everything else.
… …
1064callback with the fdatasync result code. 1230callback with the fdatasync result code.
1065 1231
1066If 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
1067detected, it will be emulated by calling C<fsync> instead. 1233detected, it will be emulated by calling C<fsync> instead.
1068 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
1069=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 1242=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1070 1243
1071Sync 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>
1072to disk (but NOT the metadata), by calling the Linux-specific 1245to disk (but NOT the metadata), by calling the Linux-specific
1073sync_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
… …
1076C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>, 1249C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1077C<IO::AIO::SYNC_FILE_RANGE_WRITE> and 1250C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1078C<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
1079manpage for details. 1252manpage for details.
1080 1253
1081=item aio_pathsync $path, $callback->($status) 1254=item aio_pathsync $pathname, $callback->($status)
1082 1255
1083This 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
1084composite request intended to sync directories after directory operations 1257composite request intended to sync directories after directory operations
1085(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
1086specific effect, but usually it makes sure that directory changes get 1259specific effect, but usually it makes sure that directory changes get
… …
1183 1356
1184Example: asynchronously lock all current and future pages into memory. 1357Example: asynchronously lock all current and future pages into memory.
1185 1358
1186 aio_mlockall IO::AIO::MCL_FUTURE; 1359 aio_mlockall IO::AIO::MCL_FUTURE;
1187 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.
1405
1188=item aio_group $callback->(...) 1406=item aio_group $callback->(...)
1189 1407
1190This 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
1191container 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
1192many requests into a single, composite, request with a definite callback 1410many requests into a single, composite, request with a definite callback
… …
1228like sleep and file handle readable/writable, the overhead this creates is 1446like sleep and file handle readable/writable, the overhead this creates is
1229immense (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
1230except to put your application under artificial I/O pressure. 1448except to put your application under artificial I/O pressure.
1231 1449
1232=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 fucntionality 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
1562if the pathname would be specified directly, without a directory object,
1563e.g., these calls are functionally identical:
1564
1565 aio_stat "somefile", sub { ... };
1566 aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
1567
1568=back
1569
1233 1570
1234=head2 IO::AIO::REQ CLASS 1571=head2 IO::AIO::REQ CLASS
1235 1572
1236All non-aggregate C<aio_*> functions return an object of this class when 1573All non-aggregate C<aio_*> functions return an object of this class when
1237called in non-void context. 1574called in non-void context.
… …
1355 1692
1356Sets a feeder/generator on this group: every group can have an attached 1693Sets a feeder/generator on this group: every group can have an attached
1357generator that generates requests if idle. The idea behind this is that, 1694generator that generates requests if idle. The idea behind this is that,
1358although you could just queue as many requests as you want in a group, 1695although you could just queue as many requests as you want in a group,
1359this might starve other requests for a potentially long time. For example, 1696this might starve other requests for a potentially long time. For example,
1360C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests, 1697C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1361delaying any later requests for a long time. 1698requests, delaying any later requests for a long time.
1362 1699
1363To avoid this, and allow incremental generation of requests, you can 1700To avoid this, and allow incremental generation of requests, you can
1364instead a group and set a feeder on it that generates those requests. The 1701instead a group and set a feeder on it that generates those requests. The
1365feed callback will be called whenever there are few enough (see C<limit>, 1702feed callback will be called whenever there are few enough (see C<limit>,
1366below) requests active in the group itself and is expected to queue more 1703below) requests active in the group itself and is expected to queue more
… …
1645 1982
1646=item IO::AIO::fadvise $fh, $offset, $len, $advice 1983=item IO::AIO::fadvise $fh, $offset, $len, $advice
1647 1984
1648Simply calls the C<posix_fadvise> function (see its 1985Simply calls the C<posix_fadvise> function (see its
1649manpage for details). The following advice constants are 1986manpage for details). The following advice constants are
1650avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>, 1987available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1651C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>, 1988C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1652C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>. 1989C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1653 1990
1654On systems that do not implement C<posix_fadvise>, this function returns 1991On systems that do not implement C<posix_fadvise>, this function returns
1655ENOSYS, otherwise the return value of C<posix_fadvise>. 1992ENOSYS, otherwise the return value of C<posix_fadvise>.
1656 1993
1657=item IO::AIO::madvise $scalar, $offset, $len, $advice 1994=item IO::AIO::madvise $scalar, $offset, $len, $advice
1658 1995
1659Simply calls the C<posix_madvise> function (see its 1996Simply calls the C<posix_madvise> function (see its
1660manpage for details). The following advice constants are 1997manpage for details). The following advice constants are
1661avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 1998available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1662C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 1999C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1663 2000
1664On systems that do not implement C<posix_madvise>, this function returns 2001On systems that do not implement C<posix_madvise>, this function returns
1665ENOSYS, otherwise the return value of C<posix_madvise>. 2002ENOSYS, otherwise the return value of C<posix_madvise>.
1666 2003
1667=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2004=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1668 2005
1669Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2006Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1670$scalar (see its manpage for details). The following protect 2007$scalar (see its manpage for details). The following protect
1671constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2008constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1672C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2009C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1673 2010
1674On systems that do not implement C<mprotect>, this function returns 2011On systems that do not implement C<mprotect>, this function returns
1675ENOSYS, otherwise the return value of C<mprotect>. 2012ENOSYS, otherwise the return value of C<mprotect>.
1676 2013
1677=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2014=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1678 2015
1679Memory-maps a file (or anonymous memory range) and attaches it to the 2016Memory-maps a file (or anonymous memory range) and attaches it to the
1680given C<$scalar>, which will act like a string scalar. 2017given C<$scalar>, which will act like a string scalar. Returns true on
2018success, and false otherwise.
1681 2019
1682The only operations allowed on the scalar are C<substr>/C<vec> that don't 2020The only operations allowed on the scalar are C<substr>/C<vec> that don't
1683change the string length, and most read-only operations such as copying it 2021change the string length, and most read-only operations such as copying it
1684or searching it with regexes and so on. 2022or searching it with regexes and so on.
1685 2023
… …
1738Calls the C<munlockall> function. 2076Calls the C<munlockall> function.
1739 2077
1740On systems that do not implement C<munlockall>, this function returns 2078On systems that do not implement C<munlockall>, this function returns
1741ENOSYS, otherwise the return value of C<munlockall>. 2079ENOSYS, otherwise the return value of C<munlockall>.
1742 2080
2081=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
2082
2083Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
2084C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
2085should be the file offset.
2086
2087C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
2088silently corrupt the data in this case.
2089
2090The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
2091C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
2092C<IO::AIO::SPLICE_F_GIFT>.
2093
2094See the C<splice(2)> manpage for details.
2095
2096=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2097
2098Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
2099description for C<IO::AIO::splice> above for details.
2100
1743=back 2101=back
1744 2102
1745=cut 2103=cut
1746 2104
1747min_parallel 8; 2105min_parallel 8;
… …
1781 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno => 2139 Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1782 \&IO::AIO::poll_cb); 2140 \&IO::AIO::poll_cb);
1783 2141
1784=head2 FORK BEHAVIOUR 2142=head2 FORK BEHAVIOUR
1785 2143
1786This module should do "the right thing" when the process using it forks: 2144Usage of pthreads in a program changes the semantics of fork
2145considerably. Specifically, only async-safe functions can be called after
2146fork. Perl doesn't know about this, so in general, you cannot call fork
2147with defined behaviour in perl if pthreads are involved. IO::AIO uses
2148pthreads, so this applies, but many other extensions and (for inexplicable
2149reasons) perl itself often is linked against pthreads, so this limitation
2150applies to quite a lot of perls.
1787 2151
1788Before the fork, IO::AIO enters a quiescent state where no requests 2152This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1789can be added in other threads and no results will be processed. After 2153only works in the process that loaded it. Forking is fully supported, but
1790the fork the parent simply leaves the quiescent state and continues 2154using IO::AIO in the child is not.
1791request/result processing, while the child frees the request/result queue
1792(so that the requests started before the fork will only be handled in the
1793parent). Threads will be started on demand until the limit set in the
1794parent process has been reached again.
1795 2155
1796In short: the parent will, after a short pause, continue as if fork had 2156You might get around by not I<using> IO::AIO before (or after)
1797not been called, while the child will act as if IO::AIO has not been used 2157forking. You could also try to call the L<IO::AIO::reinit> function in the
1798yet. 2158child:
2159
2160=over 4
2161
2162=item IO::AIO::reinit
2163
2164Abandons all current requests and I/O threads and simply reinitialises all
2165data structures. This is not an operation supported by any standards, but
2166happens to work on GNU/Linux and some newer BSD systems.
2167
2168The only reasonable use for this function is to call it after forking, if
2169C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
2170the process will result in undefined behaviour. Calling it at any time
2171will also result in any undefined (by POSIX) behaviour.
2172
2173=back
1799 2174
1800=head2 MEMORY USAGE 2175=head2 MEMORY USAGE
1801 2176
1802Per-request usage: 2177Per-request usage:
1803 2178

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