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Revision 1.240 by root, Mon Dec 17 06:18:39 2012 UTC vs.
Revision 1.275 by root, Fri Sep 22 05:20:39 2017 UTC

1=head1 NAME 1=head1 NAME
2 2
3IO::AIO - Asynchronous Input/Output 3IO::AIO - Asynchronous/Advanced Input/Output
4 4
5=head1 SYNOPSIS 5=head1 SYNOPSIS
6 6
7 use IO::AIO; 7 use IO::AIO;
8 8
… …
58not well-supported or restricted (GNU/Linux doesn't allow them on normal 58not well-supported or restricted (GNU/Linux doesn't allow them on normal
59files currently, for example), and they would only support aio_read and 59files currently, for example), and they would only support aio_read and
60aio_write, so the remaining functionality would have to be implemented 60aio_write, so the remaining functionality would have to be implemented
61using threads anyway. 61using threads anyway.
62 62
63In addition to asynchronous I/O, this module also exports some rather
64arcane interfaces, such as C<madvise> or linux's C<splice> system call,
65which is why the C<A> in C<AIO> can also mean I<advanced>.
66
63Although the module will work in the presence of other (Perl-) threads, 67Although the module will work in the presence of other (Perl-) threads,
64it is currently not reentrant in any way, so use appropriate locking 68it is currently not reentrant in any way, so use appropriate locking
65yourself, always call C<poll_cb> from within the same thread, or never 69yourself, always call C<poll_cb> from within the same thread, or never
66call C<poll_cb> (or other C<aio_> functions) recursively. 70call C<poll_cb> (or other C<aio_> functions) recursively.
67 71
68=head2 EXAMPLE 72=head2 EXAMPLE
69 73
70This is a simple example that uses the EV module and loads 74This is a simple example that uses the EV module and loads
71F</etc/passwd> asynchronously: 75F</etc/passwd> asynchronously:
72 76
73 use Fcntl;
74 use EV; 77 use EV;
75 use IO::AIO; 78 use IO::AIO;
76 79
77 # register the IO::AIO callback with EV 80 # register the IO::AIO callback with EV
78 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb; 81 my $aio_w = EV::io IO::AIO::poll_fileno, EV::READ, \&IO::AIO::poll_cb;
… …
95 98
96 # file contents now in $contents 99 # file contents now in $contents
97 print $contents; 100 print $contents;
98 101
99 # exit event loop and program 102 # exit event loop and program
100 EV::unloop; 103 EV::break;
101 }; 104 };
102 }; 105 };
103 106
104 # possibly queue up other requests, or open GUI windows, 107 # possibly queue up other requests, or open GUI windows,
105 # check for sockets etc. etc. 108 # check for sockets etc. etc.
106 109
107 # process events as long as there are some: 110 # process events as long as there are some:
108 EV::loop; 111 EV::run;
109 112
110=head1 REQUEST ANATOMY AND LIFETIME 113=head1 REQUEST ANATOMY AND LIFETIME
111 114
112Every C<aio_*> function creates a request. which is a C data structure not 115Every C<aio_*> function creates a request. which is a C data structure not
113directly visible to Perl. 116directly visible to Perl.
… …
168use common::sense; 171use common::sense;
169 172
170use base 'Exporter'; 173use base 'Exporter';
171 174
172BEGIN { 175BEGIN {
173 our $VERSION = '4.18'; 176 our $VERSION = 4.35;
174 177
175 our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close 178 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 179 aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177 aio_scandir aio_symlink aio_readlink aio_realpath aio_sync 180 aio_scandir aio_symlink aio_readlink aio_realpath aio_fcntl aio_ioctl
178 aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate 181 aio_sync aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range
179 aio_pathsync aio_readahead aio_fiemap 182 aio_pathsync aio_readahead aio_fiemap aio_allocate
180 aio_rename aio_link aio_move aio_copy aio_group 183 aio_rename aio_rename2 aio_link aio_move aio_copy aio_group
181 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown 184 aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
182 aio_chmod aio_utime aio_truncate 185 aio_chmod aio_utime aio_truncate
183 aio_msync aio_mtouch aio_mlock aio_mlockall 186 aio_msync aio_mtouch aio_mlock aio_mlockall
184 aio_statvfs 187 aio_statvfs
185 aio_wd); 188 aio_wd);
… …
228 aio_unlink $pathname, $callback->($status) 231 aio_unlink $pathname, $callback->($status)
229 aio_mknod $pathname, $mode, $dev, $callback->($status) 232 aio_mknod $pathname, $mode, $dev, $callback->($status)
230 aio_link $srcpath, $dstpath, $callback->($status) 233 aio_link $srcpath, $dstpath, $callback->($status)
231 aio_symlink $srcpath, $dstpath, $callback->($status) 234 aio_symlink $srcpath, $dstpath, $callback->($status)
232 aio_readlink $pathname, $callback->($link) 235 aio_readlink $pathname, $callback->($link)
233 aio_realpath $pathname, $callback->($link) 236 aio_realpath $pathname, $callback->($path)
234 aio_rename $srcpath, $dstpath, $callback->($status) 237 aio_rename $srcpath, $dstpath, $callback->($status)
238 aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
235 aio_mkdir $pathname, $mode, $callback->($status) 239 aio_mkdir $pathname, $mode, $callback->($status)
236 aio_rmdir $pathname, $callback->($status) 240 aio_rmdir $pathname, $callback->($status)
237 aio_readdir $pathname, $callback->($entries) 241 aio_readdir $pathname, $callback->($entries)
238 aio_readdirx $pathname, $flags, $callback->($entries, $flags) 242 aio_readdirx $pathname, $flags, $callback->($entries, $flags)
239 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST 243 IO::AIO::READDIR_DENTS IO::AIO::READDIR_DIRS_FIRST
… …
241 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs) 245 aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
242 aio_load $pathname, $data, $callback->($status) 246 aio_load $pathname, $data, $callback->($status)
243 aio_copy $srcpath, $dstpath, $callback->($status) 247 aio_copy $srcpath, $dstpath, $callback->($status)
244 aio_move $srcpath, $dstpath, $callback->($status) 248 aio_move $srcpath, $dstpath, $callback->($status)
245 aio_rmtree $pathname, $callback->($status) 249 aio_rmtree $pathname, $callback->($status)
250 aio_fcntl $fh, $cmd, $arg, $callback->($status)
251 aio_ioctl $fh, $request, $buf, $callback->($status)
246 aio_sync $callback->($status) 252 aio_sync $callback->($status)
247 aio_syncfs $fh, $callback->($status) 253 aio_syncfs $fh, $callback->($status)
248 aio_fsync $fh, $callback->($status) 254 aio_fsync $fh, $callback->($status)
249 aio_fdatasync $fh, $callback->($status) 255 aio_fdatasync $fh, $callback->($status)
250 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status) 256 aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
251 aio_pathsync $pathname, $callback->($status) 257 aio_pathsync $pathname, $callback->($status)
252 aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 258 aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
253 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 259 aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
254 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status) 260 aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
255 aio_mlockall $flags, $callback->($status) 261 aio_mlockall $flags, $callback->($status)
256 aio_group $callback->(...) 262 aio_group $callback->(...)
257 aio_nop $callback->() 263 aio_nop $callback->()
… …
271 IO::AIO::idle_timeout $seconds 277 IO::AIO::idle_timeout $seconds
272 IO::AIO::max_outstanding $maxreqs 278 IO::AIO::max_outstanding $maxreqs
273 IO::AIO::nreqs 279 IO::AIO::nreqs
274 IO::AIO::nready 280 IO::AIO::nready
275 IO::AIO::npending 281 IO::AIO::npending
282 IO::AIO::min_fdlimit $nfd;
276 283
277 IO::AIO::sendfile $ofh, $ifh, $offset, $count 284 IO::AIO::sendfile $ofh, $ifh, $offset, $count
278 IO::AIO::fadvise $fh, $offset, $len, $advice 285 IO::AIO::fadvise $fh, $offset, $len, $advice
279 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]] 286 IO::AIO::mmap $scalar, $length, $prot, $flags[, $fh[, $offset]]
280 IO::AIO::munmap $scalar 287 IO::AIO::munmap $scalar
… …
395following POSIX and non-POSIX constants are available (missing ones on 402following POSIX and non-POSIX constants are available (missing ones on
396your system are, as usual, C<0>): 403your system are, as usual, C<0>):
397 404
398C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>, 405C<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>, 406C<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>. 407C<O_RSYNC>, C<O_SYNC>, C<O_PATH>, C<O_TMPFILE>, and C<O_TTY_INIT>.
401 408
402 409
403=item aio_close $fh, $callback->($status) 410=item aio_close $fh, $callback->($status)
404 411
405Asynchronously close a file and call the callback with the result 412Asynchronously close a file and call the callback with the result
… …
440=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 447=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
441 448
442=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval) 449=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
443 450
444Reads or writes C<$length> bytes from or to the specified C<$fh> and 451Reads or writes C<$length> bytes from or to the specified C<$fh> and
445C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> 452C<$offset> into the scalar given by C<$data> and offset C<$dataoffset> and
446and calls the callback without the actual number of bytes read (or -1 on 453calls the callback with the actual number of bytes transferred (or -1 on
447error, just like the syscall). 454error, just like the syscall).
448 455
449C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to 456C<aio_read> will, like C<sysread>, shrink or grow the C<$data> scalar to
450offset plus the actual number of bytes read. 457offset plus the actual number of bytes read.
451 458
… …
509As native sendfile syscalls (as practically any non-POSIX interface hacked 516As native sendfile syscalls (as practically any non-POSIX interface hacked
510together in a hurry to improve benchmark numbers) tend to be rather buggy 517together in a hurry to improve benchmark numbers) tend to be rather buggy
511on many systems, this implementation tries to work around some known bugs 518on many systems, this implementation tries to work around some known bugs
512in Linux and FreeBSD kernels (probably others, too), but that might fail, 519in Linux and FreeBSD kernels (probably others, too), but that might fail,
513so you really really should check the return value of C<aio_sendfile> - 520so you really really should check the return value of C<aio_sendfile> -
514fewre bytes than expected might have been transferred. 521fewer bytes than expected might have been transferred.
515 522
516 523
517=item aio_readahead $fh,$offset,$length, $callback->($retval) 524=item aio_readahead $fh,$offset,$length, $callback->($retval)
518 525
519C<aio_readahead> populates the page cache with data from a file so that 526C<aio_readahead> populates the page cache with data from a file so that
… …
523whole pages, so that offset is effectively rounded down to a page boundary 530whole pages, so that offset is effectively rounded down to a page boundary
524and bytes are read up to the next page boundary greater than or equal to 531and bytes are read up to the next page boundary greater than or equal to
525(off-set+length). C<aio_readahead> does not read beyond the end of the 532(off-set+length). C<aio_readahead> does not read beyond the end of the
526file. The current file offset of the file is left unchanged. 533file. The current file offset of the file is left unchanged.
527 534
528If that syscall doesn't exist (likely if your OS isn't Linux) it will be 535If that syscall doesn't exist (likely if your kernel isn't Linux) it will
529emulated by simply reading the data, which would have a similar effect. 536be emulated by simply reading the data, which would have a similar effect.
530 537
531 538
532=item aio_stat $fh_or_path, $callback->($status) 539=item aio_stat $fh_or_path, $callback->($status)
533 540
534=item aio_lstat $fh, $callback->($status) 541=item aio_lstat $fh, $callback->($status)
… …
603 namemax => 255, 610 namemax => 255,
604 frsize => 1024, 611 frsize => 1024,
605 fsid => 1810 612 fsid => 1810
606 } 613 }
607 614
608Here is a (likely partial) list of fsid values used by Linux - it is safe 615Here is a (likely partial - send me updates!) list of fsid values used by
609to hardcode these when the $^O is C<linux>: 616Linux - it is safe to hardcode these when C<$^O> is C<linux>:
610 617
611 0x0000adf5 adfs 618 0x0000adf5 adfs
612 0x0000adff affs 619 0x0000adff affs
613 0x5346414f afs 620 0x5346414f afs
614 0x09041934 anon-inode filesystem 621 0x09041934 anon-inode filesystem
… …
627 0x00001373 devfs 634 0x00001373 devfs
628 0x00001cd1 devpts 635 0x00001cd1 devpts
629 0x0000f15f ecryptfs 636 0x0000f15f ecryptfs
630 0x00414a53 efs 637 0x00414a53 efs
631 0x0000137d ext 638 0x0000137d ext
632 0x0000ef53 ext2/ext3 639 0x0000ef53 ext2/ext3/ext4
633 0x0000ef51 ext2 640 0x0000ef51 ext2
641 0xf2f52010 f2fs
634 0x00004006 fat 642 0x00004006 fat
635 0x65735546 fuseblk 643 0x65735546 fuseblk
636 0x65735543 fusectl 644 0x65735543 fusectl
637 0x0bad1dea futexfs 645 0x0bad1dea futexfs
638 0x01161970 gfs2 646 0x01161970 gfs2
639 0x47504653 gpfs 647 0x47504653 gpfs
640 0x00004244 hfs 648 0x00004244 hfs
641 0xf995e849 hpfs 649 0xf995e849 hpfs
650 0x00c0ffee hostfs
642 0x958458f6 hugetlbfs 651 0x958458f6 hugetlbfs
643 0x2bad1dea inotifyfs 652 0x2bad1dea inotifyfs
644 0x00009660 isofs 653 0x00009660 isofs
645 0x000072b6 jffs2 654 0x000072b6 jffs2
646 0x3153464a jfs 655 0x3153464a jfs
… …
661 0x00009fa1 openprom 670 0x00009fa1 openprom
662 0x7461636F ocfs2 671 0x7461636F ocfs2
663 0x00009fa0 proc 672 0x00009fa0 proc
664 0x6165676c pstorefs 673 0x6165676c pstorefs
665 0x0000002f qnx4 674 0x0000002f qnx4
675 0x68191122 qnx6
666 0x858458f6 ramfs 676 0x858458f6 ramfs
667 0x52654973 reiserfs 677 0x52654973 reiserfs
668 0x00007275 romfs 678 0x00007275 romfs
669 0x67596969 rpc_pipefs 679 0x67596969 rpc_pipefs
670 0x73636673 securityfs 680 0x73636673 securityfs
… …
723Works like truncate(2) or ftruncate(2). 733Works like truncate(2) or ftruncate(2).
724 734
725 735
726=item aio_allocate $fh, $mode, $offset, $len, $callback->($status) 736=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
727 737
728Allocates or freed disk space according to the C<$mode> argument. See the 738Allocates or frees disk space according to the C<$mode> argument. See the
729linux C<fallocate> docuemntation for details. 739linux C<fallocate> documentation for details.
730 740
731C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> 741C<$mode> is usually C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE> to allocate
732to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | 742space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE | IO::AIO::FALLOC_FL_KEEP_SIZE>,
733IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range. 743to deallocate a file range.
744
745IO::AIO also supports C<FALLOC_FL_COLLAPSE_RANGE>, to remove a range
746(without leaving a hole), C<FALLOC_FL_ZERO_RANGE>, to zero a range,
747C<FALLOC_FL_INSERT_RANGE> to insert a range and C<FALLOC_FL_UNSHARE_RANGE>
748to unshare shared blocks (see your L<fallocate(2)> manpage).
734 749
735The file system block size used by C<fallocate> is presumably the 750The file system block size used by C<fallocate> is presumably the
736C<f_bsize> returned by C<statvfs>. 751C<f_bsize> returned by C<statvfs>, but different filesystems and filetypes
752can dictate other limitations.
737 753
738If C<fallocate> isn't available or cannot be emulated (currently no 754If C<fallocate> isn't available or cannot be emulated (currently no
739emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>. 755emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
740 756
741 757
… …
795=item aio_rename $srcpath, $dstpath, $callback->($status) 811=item aio_rename $srcpath, $dstpath, $callback->($status)
796 812
797Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as 813Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
798rename(2) and call the callback with the result code. 814rename(2) and call the callback with the result code.
799 815
816On systems that support the AIO::WD working directory abstraction
817natively, the case C<[$wd, "."]> as C<$srcpath> is specialcased - instead
818of failing, C<rename> is called on the absolute path of C<$wd>.
819
820
821=item aio_rename2 $srcpath, $dstpath, $flags, $callback->($status)
822
823Basically a version of C<aio_rename> with an additional C<$flags>
824argument. Calling this with C<$flags=0> is the same as calling
825C<aio_rename>.
826
827Non-zero flags are currently only supported on GNU/Linux systems that
828support renameat2. Other systems fail with C<ENOSYS> in this case.
829
830The following constants are available (missing ones are, as usual C<0>),
831see renameat2(2) for details:
832
833C<IO::AIO::RENAME_NOREPLACE>, C<IO::AIO::RENAME_EXCHANGE>
834and C<IO::AIO::RENAME_WHITEOUT>.
835
800 836
801=item aio_mkdir $pathname, $mode, $callback->($status) 837=item aio_mkdir $pathname, $mode, $callback->($status)
802 838
803Asynchronously mkdir (create) a directory and call the callback with 839Asynchronously mkdir (create) a directory and call the callback with
804the result code. C<$mode> will be modified by the umask at the time the 840the result code. C<$mode> will be modified by the umask at the time the
… …
807 843
808=item aio_rmdir $pathname, $callback->($status) 844=item aio_rmdir $pathname, $callback->($status)
809 845
810Asynchronously rmdir (delete) a directory and call the callback with the 846Asynchronously rmdir (delete) a directory and call the callback with the
811result code. 847result code.
848
849On systems that support the AIO::WD working directory abstraction
850natively, the case C<[$wd, "."]> is specialcased - instead of failing,
851C<rmdir> is called on the absolute path of C<$wd>.
812 852
813 853
814=item aio_readdir $pathname, $callback->($entries) 854=item aio_readdir $pathname, $callback->($entries)
815 855
816Unlike the POSIX call of the same name, C<aio_readdir> reads an entire 856Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
… …
918=item aio_copy $srcpath, $dstpath, $callback->($status) 958=item aio_copy $srcpath, $dstpath, $callback->($status)
919 959
920Try to copy the I<file> (directories not supported as either source or 960Try to copy the I<file> (directories not supported as either source or
921destination) from C<$srcpath> to C<$dstpath> and call the callback with 961destination) from C<$srcpath> to C<$dstpath> and call the callback with
922a status of C<0> (ok) or C<-1> (error, see C<$!>). 962a status of C<0> (ok) or C<-1> (error, see C<$!>).
963
964Existing destination files will be truncated.
923 965
924This is a composite request that creates the destination file with 966This is a composite request that creates the destination file with
925mode 0200 and copies the contents of the source file into it using 967mode 0200 and copies the contents of the source file into it using
926C<aio_sendfile>, followed by restoring atime, mtime, access mode and 968C<aio_sendfile>, followed by restoring atime, mtime, access mode and
927uid/gid, in that order. 969uid/gid, in that order.
… …
1213 }; 1255 };
1214 1256
1215 $grp 1257 $grp
1216} 1258}
1217 1259
1260=item aio_fcntl $fh, $cmd, $arg, $callback->($status)
1261
1262=item aio_ioctl $fh, $request, $buf, $callback->($status)
1263
1264These work just like the C<fcntl> and C<ioctl> built-in functions, except
1265they execute asynchronously and pass the return value to the callback.
1266
1267Both calls can be used for a lot of things, some of which make more sense
1268to run asynchronously in their own thread, while some others make less
1269sense. For example, calls that block waiting for external events, such
1270as locking, will also lock down an I/O thread while it is waiting, which
1271can deadlock the whole I/O system. At the same time, there might be no
1272alternative to using a thread to wait.
1273
1274So in general, you should only use these calls for things that do
1275(filesystem) I/O, not for things that wait for other events (network,
1276other processes), although if you are careful and know what you are doing,
1277you still can.
1278
1279The following constants are available (missing ones are, as usual C<0>):
1280
1281C<F_DUPFD_CLOEXEC>,
1282
1283C<F_OFD_GETLK>, C<F_OFD_SETLK>, C<F_OFD_GETLKW>,
1284
1285C<FIFREEZE>, C<FITHAW>, C<FITRIM>, C<FICLONE>, C<FICLONERANGE>, C<FIDEDUPERANGE>.
1286
1287C<FS_IOC_GETFLAGS>, C<FS_IOC_SETFLAGS>, C<FS_IOC_GETVERSION>, C<FS_IOC_SETVERSION>,
1288C<FS_IOC_FIEMAP>.
1289
1290C<FS_IOC_FSGETXATTR>, C<FS_IOC_FSSETXATTR>, C<FS_IOC_SET_ENCRYPTION_POLICY>,
1291C<FS_IOC_GET_ENCRYPTION_PWSALT>, C<FS_IOC_GET_ENCRYPTION_POLICY>, C<FS_KEY_DESCRIPTOR_SIZE>.
1292
1293C<FS_SECRM_FL>, C<FS_UNRM_FL>, C<FS_COMPR_FL>, C<FS_SYNC_FL>, C<FS_IMMUTABLE_FL>,
1294C<FS_APPEND_FL>, C<FS_NODUMP_FL>, C<FS_NOATIME_FL>, C<FS_DIRTY_FL>,
1295C<FS_COMPRBLK_FL>, C<FS_NOCOMP_FL>, C<FS_ENCRYPT_FL>, C<FS_BTREE_FL>,
1296C<FS_INDEX_FL>, C<FS_JOURNAL_DATA_FL>, C<FS_NOTAIL_FL>, C<FS_DIRSYNC_FL>, C<FS_TOPDIR_FL>,
1297C<FS_FL_USER_MODIFIABLE>.
1298
1299C<FS_XFLAG_REALTIME>, C<FS_XFLAG_PREALLOC>, C<FS_XFLAG_IMMUTABLE>, C<FS_XFLAG_APPEND>,
1300C<FS_XFLAG_SYNC>, C<FS_XFLAG_NOATIME>, C<FS_XFLAG_NODUMP>, C<FS_XFLAG_RTINHERIT>,
1301C<FS_XFLAG_PROJINHERIT>, C<FS_XFLAG_NOSYMLINKS>, C<FS_XFLAG_EXTSIZE>, C<FS_XFLAG_EXTSZINHERIT>,
1302C<FS_XFLAG_NODEFRAG>, C<FS_XFLAG_FILESTREAM>, C<FS_XFLAG_DAX>, C<FS_XFLAG_HASATTR>,
1303
1218=item aio_sync $callback->($status) 1304=item aio_sync $callback->($status)
1219 1305
1220Asynchronously call sync and call the callback when finished. 1306Asynchronously call sync and call the callback when finished.
1221 1307
1222=item aio_fsync $fh, $callback->($status) 1308=item aio_fsync $fh, $callback->($status)
… …
1290 }; 1376 };
1291 1377
1292 $grp 1378 $grp
1293} 1379}
1294 1380
1295=item aio_msync $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1381=item aio_msync $scalar, $offset = 0, $length = undef, flags = MS_SYNC, $callback->($status)
1296 1382
1297This is a rather advanced IO::AIO call, which only works on mmap(2)ed 1383This is a rather advanced IO::AIO call, which only works on mmap(2)ed
1298scalars (see the C<IO::AIO::mmap> function, although it also works on data 1384scalars (see the C<IO::AIO::mmap> function, although it also works on data
1299scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the 1385scalars managed by the L<Sys::Mmap> or L<Mmap> modules, note that the
1300scalar must only be modified in-place while an aio operation is pending on 1386scalar must only be modified in-place while an aio operation is pending on
… …
1302 1388
1303It calls the C<msync> function of your OS, if available, with the memory 1389It calls the C<msync> function of your OS, if available, with the memory
1304area starting at C<$offset> in the string and ending C<$length> bytes 1390area starting at C<$offset> in the string and ending C<$length> bytes
1305later. If C<$length> is negative, counts from the end, and if C<$length> 1391later. If C<$length> is negative, counts from the end, and if C<$length>
1306is C<undef>, then it goes till the end of the string. The flags can be 1392is C<undef>, then it goes till the end of the string. The flags can be
1307a combination of C<IO::AIO::MS_ASYNC>, C<IO::AIO::MS_INVALIDATE> and 1393either C<IO::AIO::MS_ASYNC> or C<IO::AIO::MS_SYNC>, plus an optional
1308C<IO::AIO::MS_SYNC>. 1394C<IO::AIO::MS_INVALIDATE>.
1309 1395
1310=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status) 1396=item aio_mtouch $scalar, $offset = 0, $length = undef, flags = 0, $callback->($status)
1311 1397
1312This is a rather advanced IO::AIO call, which works best on mmap(2)ed 1398This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1313scalars. 1399scalars.
… …
1493 aio_stat [$etcdir, "passwd"], sub { 1579 aio_stat [$etcdir, "passwd"], sub {
1494 # yay 1580 # yay
1495 }; 1581 };
1496 }; 1582 };
1497 1583
1498That C<aio_wd> is a request and not a normal function shows that creating 1584The fact that C<aio_wd> is a request and not a normal function shows that
1499an IO::AIO::WD object is itself a potentially blocking operation, which is 1585creating an IO::AIO::WD object is itself a potentially blocking operation,
1500why it is done asynchronously. 1586which is why it is done asynchronously.
1501 1587
1502To stat the directory obtained with C<aio_wd> above, one could write 1588To stat the directory obtained with C<aio_wd> above, one could write
1503either of the following three request calls: 1589either of the following three request calls:
1504 1590
1505 aio_lstat "/etc" , sub { ... # pathname as normal string 1591 aio_lstat "/etc" , sub { ... # pathname as normal string
… …
1548passing C<undef> as working directory component of a pathname fails the 1634passing 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 1635request 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 1636C<aio_wd> callback, as future requests using the value will fail in the
1551expected way. 1637expected way.
1552 1638
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 1639=item IO::AIO::CWD
1557 1640
1558This is a compiletime constant (object) that represents the process 1641This is a compiletime constant (object) that represents the process
1559current working directory. 1642current working directory.
1560 1643
… …
1572 1655
1573 aio_realpath $wd, sub { 1656 aio_realpath $wd, sub {
1574 warn "path is $_[0]\n"; 1657 warn "path is $_[0]\n";
1575 }; 1658 };
1576 1659
1660Currently, C<aio_statvfs> always, and C<aio_rename> and C<aio_rmdir>
1661sometimes, fall back to using an absolue path.
1577 1662
1578=head2 IO::AIO::REQ CLASS 1663=head2 IO::AIO::REQ CLASS
1579 1664
1580All non-aggregate C<aio_*> functions return an object of this class when 1665All non-aggregate C<aio_*> functions return an object of this class when
1581called in non-void context. 1666called in non-void context.
… …
1925 2010
1926This is a very bad function to use in interactive programs because it 2011This is a very bad function to use in interactive programs because it
1927blocks, and a bad way to reduce concurrency because it is inexact: Better 2012blocks, and a bad way to reduce concurrency because it is inexact: Better
1928use an C<aio_group> together with a feed callback. 2013use an C<aio_group> together with a feed callback.
1929 2014
1930It's main use is in scripts without an event loop - when you want to stat 2015Its main use is in scripts without an event loop - when you want to stat
1931a lot of files, you can write somehting like this: 2016a lot of files, you can write something like this:
1932 2017
1933 IO::AIO::max_outstanding 32; 2018 IO::AIO::max_outstanding 32;
1934 2019
1935 for my $path (...) { 2020 for my $path (...) {
1936 aio_stat $path , ...; 2021 aio_stat $path , ...;
… …
1975 2060
1976=back 2061=back
1977 2062
1978=head3 MISCELLANEOUS FUNCTIONS 2063=head3 MISCELLANEOUS FUNCTIONS
1979 2064
1980IO::AIO implements some functions that might be useful, but are not 2065IO::AIO implements some functions that are useful when you want to use
1981asynchronous. 2066some "Advanced I/O" function not available to in Perl, without going the
2067"Asynchronous I/O" route. Many of these have an asynchronous C<aio_*>
2068counterpart.
1982 2069
1983=over 4 2070=over 4
2071
2072=item $numfd = IO::AIO::get_fdlimit
2073
2074Tries to find the current file descriptor limit and returns it, or
2075C<undef> and sets C<$!> in case of an error. The limit is one larger than
2076the highest valid file descriptor number.
2077
2078=item IO::AIO::min_fdlimit [$numfd]
2079
2080Try to increase the current file descriptor limit(s) to at least C<$numfd>
2081by changing the soft or hard file descriptor resource limit. If C<$numfd>
2082is missing, it will try to set a very high limit, although this is not
2083recommended when you know the actual minimum that you require.
2084
2085If the limit cannot be raised enough, the function makes a best-effort
2086attempt to increase the limit as much as possible, using various
2087tricks, while still failing. You can query the resulting limit using
2088C<IO::AIO::get_fdlimit>.
2089
2090If an error occurs, returns C<undef> and sets C<$!>.
1984 2091
1985=item IO::AIO::sendfile $ofh, $ifh, $offset, $count 2092=item IO::AIO::sendfile $ofh, $ifh, $offset, $count
1986 2093
1987Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>, 2094Calls the C<eio_sendfile_sync> function, which is like C<aio_sendfile>,
1988but is blocking (this makes most sense if you know the input data is 2095but is blocking (this makes most sense if you know the input data is
… …
2005=item IO::AIO::madvise $scalar, $offset, $len, $advice 2112=item IO::AIO::madvise $scalar, $offset, $len, $advice
2006 2113
2007Simply calls the C<posix_madvise> function (see its 2114Simply calls the C<posix_madvise> function (see its
2008manpage for details). The following advice constants are 2115manpage for details). The following advice constants are
2009available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>, 2116available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
2010C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>. 2117C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>,
2118C<IO::AIO::MADV_DONTNEED>.
2119
2120If C<$offset> is negative, counts from the end. If C<$length> is negative,
2121the remaining length of the C<$scalar> is used. If possible, C<$length>
2122will be reduced to fit into the C<$scalar>.
2011 2123
2012On systems that do not implement C<posix_madvise>, this function returns 2124On systems that do not implement C<posix_madvise>, this function returns
2013ENOSYS, otherwise the return value of C<posix_madvise>. 2125ENOSYS, otherwise the return value of C<posix_madvise>.
2014 2126
2015=item IO::AIO::mprotect $scalar, $offset, $len, $protect 2127=item IO::AIO::mprotect $scalar, $offset, $len, $protect
… …
2017Simply calls the C<mprotect> function on the preferably AIO::mmap'ed 2129Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
2018$scalar (see its manpage for details). The following protect 2130$scalar (see its manpage for details). The following protect
2019constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>, 2131constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
2020C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>. 2132C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
2021 2133
2134If C<$offset> is negative, counts from the end. If C<$length> is negative,
2135the remaining length of the C<$scalar> is used. If possible, C<$length>
2136will be reduced to fit into the C<$scalar>.
2137
2022On systems that do not implement C<mprotect>, this function returns 2138On systems that do not implement C<mprotect>, this function returns
2023ENOSYS, otherwise the return value of C<mprotect>. 2139ENOSYS, otherwise the return value of C<mprotect>.
2024 2140
2025=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset] 2141=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
2026 2142
2027Memory-maps a file (or anonymous memory range) and attaches it to the 2143Memory-maps a file (or anonymous memory range) and attaches it to the
2028given C<$scalar>, which will act like a string scalar. Returns true on 2144given C<$scalar>, which will act like a string scalar. Returns true on
2029success, and false otherwise. 2145success, and false otherwise.
2030 2146
2147The scalar must exist, but its contents do not matter - this means you
2148cannot use a nonexistant array or hash element. When in doubt, C<undef>
2149the scalar first.
2150
2031The only operations allowed on the scalar are C<substr>/C<vec> that don't 2151The only operations allowed on the mmapped scalar are C<substr>/C<vec>,
2032change the string length, and most read-only operations such as copying it 2152which don't change the string length, and most read-only operations such
2033or searching it with regexes and so on. 2153as copying it or searching it with regexes and so on.
2034 2154
2035Anything else is unsafe and will, at best, result in memory leaks. 2155Anything else is unsafe and will, at best, result in memory leaks.
2036 2156
2037The memory map associated with the C<$scalar> is automatically removed 2157The memory map associated with the C<$scalar> is automatically removed
2038when the C<$scalar> is destroyed, or when the C<IO::AIO::mmap> or 2158when the C<$scalar> is undef'd or destroyed, or when the C<IO::AIO::mmap>
2039C<IO::AIO::munmap> functions are called. 2159or C<IO::AIO::munmap> functions are called on it.
2040 2160
2041This calls the C<mmap>(2) function internally. See your system's manual 2161This calls the C<mmap>(2) function internally. See your system's manual
2042page for details on the C<$length>, C<$prot> and C<$flags> parameters. 2162page for details on the C<$length>, C<$prot> and C<$flags> parameters.
2043 2163
2044The C<$length> must be larger than zero and smaller than the actual 2164The C<$length> must be larger than zero and smaller than the actual
2045filesize. 2165filesize.
2046 2166
2047C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>, 2167C<$prot> is a combination of C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_EXEC>,
2048C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>, 2168C<IO::AIO::PROT_READ> and/or C<IO::AIO::PROT_WRITE>,
2049 2169
2050C<$flags> can be a combination of C<IO::AIO::MAP_SHARED> or 2170C<$flags> can be a combination of
2051C<IO::AIO::MAP_PRIVATE>, or a number of system-specific flags (when 2171C<IO::AIO::MAP_SHARED> or
2052not available, the are defined as 0): C<IO::AIO::MAP_ANONYMOUS> 2172C<IO::AIO::MAP_PRIVATE>,
2173or a number of system-specific flags (when not available, the are C<0>):
2053(which is set to C<MAP_ANON> if your system only provides this 2174C<IO::AIO::MAP_ANONYMOUS> (which is set to C<MAP_ANON> if your system only provides this constant),
2054constant), C<IO::AIO::MAP_HUGETLB>, C<IO::AIO::MAP_LOCKED>, 2175C<IO::AIO::MAP_LOCKED>,
2055C<IO::AIO::MAP_NORESERVE>, C<IO::AIO::MAP_POPULATE> or 2176C<IO::AIO::MAP_NORESERVE>,
2177C<IO::AIO::MAP_POPULATE>,
2056C<IO::AIO::MAP_NONBLOCK> 2178C<IO::AIO::MAP_NONBLOCK>,
2179C<IO::AIO::MAP_FIXED>,
2180C<IO::AIO::MAP_GROWSDOWN>,
2181C<IO::AIO::MAP_32BIT>,
2182C<IO::AIO::MAP_HUGETLB> or
2183C<IO::AIO::MAP_STACK>.
2057 2184
2058If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed. 2185If C<$fh> is C<undef>, then a file descriptor of C<-1> is passed.
2059 2186
2060C<$offset> is the offset from the start of the file - it generally must be 2187C<$offset> is the offset from the start of the file - it generally must be
2061a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>. 2188a multiple of C<IO::AIO::PAGESIZE> and defaults to C<0>.
… …
2104 2231
2105See the C<splice(2)> manpage for details. 2232See the C<splice(2)> manpage for details.
2106 2233
2107=item IO::AIO::tee $r_fh, $w_fh, $length, $flags 2234=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
2108 2235
2109Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the 2236Calls the GNU/Linux C<tee(2)> syscall, see its manpage and the
2110description for C<IO::AIO::splice> above for details. 2237description for C<IO::AIO::splice> above for details.
2238
2239=item $actual_size = IO::AIO::pipesize $r_fh[, $new_size]
2240
2241Attempts to query or change the pipe buffer size. Obviously works only
2242on pipes, and currently works only on GNU/Linux systems, and fails with
2243C<-1>/C<ENOSYS> everywhere else. If anybody knows how to influence pipe buffer
2244size on other systems, drop me a note.
2245
2246=item ($rfh, $wfh) = IO::AIO::pipe2 [$flags]
2247
2248This is a direct interface to the Linux L<pipe2(2)> system call. If
2249C<$flags> is missing or C<0>, then this should be the same as a call to
2250perl's built-in C<pipe> function and create a new pipe, and works on
2251systems that lack the pipe2 syscall. On win32, this case invokes C<_pipe
2252(..., 4096, O_BINARY)>.
2253
2254If C<$flags> is non-zero, it tries to invoke the pipe2 system call with
2255the given flags (Linux 2.6.27, glibc 2.9).
2256
2257On success, the read and write file handles are returned.
2258
2259On error, nothing will be returned. If the pipe2 syscall is missing and
2260C<$flags> is non-zero, fails with C<ENOSYS>.
2261
2262Please refer to L<pipe2(2)> for more info on the C<$flags>, but at the
2263time of this writing, C<IO::AIO::O_CLOEXEC>, C<IO::AIO::O_NONBLOCK> and
2264C<IO::AIO::O_DIRECT> (Linux 3.4, for packet-based pipes) were supported.
2111 2265
2112=back 2266=back
2113 2267
2114=cut 2268=cut
2115 2269

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