[ViewVC] Diff of: cvs/IO-AIO/AIO.pm

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.187 by root, Fri Feb 11 00:05:17 2011 UTC vs.
Revision 1.240 by root, Mon Dec 17 06:18:39 2012 UTC

…		…
168	use common::sense;	168	use common::sense;
169		169
170	use base 'Exporter';	170	use base 'Exporter';
171		171
172	BEGIN {	172	BEGIN {
173	our $VERSION = '3.72';	173	our $VERSION = '4.18';
174		174
175	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close	175	our @AIO_REQ = qw(aio_sendfile aio_seek aio_read aio_write aio_open aio_close
176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx	176	aio_stat aio_lstat aio_unlink aio_rmdir aio_readdir aio_readdirx
177	aio_scandir aio_symlink aio_readlink aio_sync aio_fsync	177	aio_scandir aio_symlink aio_readlink aio_realpath aio_sync
178	aio_fdatasync aio_sync_file_range aio_pathsync aio_readahead	178	aio_fsync aio_syncfs aio_fdatasync aio_sync_file_range aio_allocate
		179	aio_pathsync aio_readahead aio_fiemap
179	aio_rename aio_link aio_move aio_copy aio_group	180	aio_rename aio_link aio_move aio_copy aio_group
180	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown	181	aio_nop aio_mknod aio_load aio_rmtree aio_mkdir aio_chown
181	aio_chmod aio_utime aio_truncate	182	aio_chmod aio_utime aio_truncate
182	aio_msync aio_mtouch aio_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	189	min_parallel max_parallel max_idle idle_timeout
188	nreqs nready npending nthreads	190	nreqs nready npending nthreads
189	max_poll_time max_poll_reqs	191	max_poll_time max_poll_reqs
190	sendfile fadvise madvise	192	sendfile fadvise madvise
191	mmap munmap munlock munlockall);	193	mmap munmap munlock munlockall);
192		194
…		…
200		202
201	=head1 FUNCTIONS	203	=head1 FUNCTIONS
202		204
203	=head2 QUICK OVERVIEW	205	=head2 QUICK OVERVIEW
204		206
205	This section simply lists the prototypes of the most important functions	207	This section simply lists the prototypes most of the functions for
206	for quick reference. See the following sections for function-by-function	208	quick reference. See the following sections for function-by-function
207	documentation.	209	documentation.
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->(...)
…		…
258	IO::AIO::max_poll_reqs $nreqs	266	IO::AIO::max_poll_reqs $nreqs
259	IO::AIO::max_poll_time $seconds	267	IO::AIO::max_poll_time $seconds
260	IO::AIO::min_parallel $nthreads	268	IO::AIO::min_parallel $nthreads
261	IO::AIO::max_parallel $nthreads	269	IO::AIO::max_parallel $nthreads
262	IO::AIO::max_idle $nthreads	270	IO::AIO::max_idle $nthreads
		271	IO::AIO::idle_timeout $seconds
263	IO::AIO::max_outstanding $maxreqs	272	IO::AIO::max_outstanding $maxreqs
264	IO::AIO::nreqs	273	IO::AIO::nreqs
265	IO::AIO::nready	274	IO::AIO::nready
266	IO::AIO::npending	275	IO::AIO::npending
267		276
268	IO::AIO::sendfile $ofh, $ifh, $offset, $count	277	IO::AIO::sendfile $ofh, $ifh, $offset, $count
269	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
270	IO::AIO::madvise $scalar, $offset, $length, $advice	281	IO::AIO::madvise $scalar, $offset, $length, $advice
271	IO::AIO::mprotect $scalar, $offset, $length, $protect	282	IO::AIO::mprotect $scalar, $offset, $length, $protect
272	IO::AIO::munlock $scalar, $offset = 0, $length = undef	283	IO::AIO::munlock $scalar, $offset = 0, $length = undef
273	IO::AIO::munlockall	284	IO::AIO::munlockall
274		285
275	=head2 AIO REQUEST FUNCTIONS	286	=head2 API NOTES
276		287
277	All the C<aio_*> calls are more or less thin wrappers around the syscall	288	All the C<aio_*> calls are more or less thin wrappers around the syscall
278	with the same name (sans C<aio_>). The arguments are similar or identical,	289	with the same name (sans C<aio_>). The arguments are similar or identical,
279	and they all accept an additional (and optional) C<$callback> argument	290	and they all accept an additional (and optional) C<$callback> argument
280	which must be a code reference. This code reference will get called with	291	which must be a code reference. This code reference will be called after
281	the syscall return code (e.g. most syscalls return C<-1> on error, unlike	292	the syscall has been executed in an asynchronous fashion. The results
282	perl, which usually delivers "false") as its sole argument after the given	293	of the request will be passed as arguments to the callback (and, if an
283	syscall has been executed asynchronously.	294	error occured, in C<$!>) - for most requests the syscall return code (e.g.
		295	most syscalls return C<-1> on error, unlike perl, which usually delivers
		296	"false").
		297
		298	Some requests (such as C<aio_readdir>) pass the actual results and
		299	communicate failures by passing C<undef>.
284		300
285	All functions expecting a filehandle keep a copy of the filehandle	301	All functions expecting a filehandle keep a copy of the filehandle
286	internally until the request has finished.	302	internally until the request has finished.
287		303
288	All functions return request objects of type L<IO::AIO::REQ> that allow	304	All functions return request objects of type L<IO::AIO::REQ> that allow
289	further manipulation of those requests while they are in-flight.	305	further manipulation of those requests while they are in-flight.
290		306
291	The pathnames you pass to these routines I<must> be absolute and	307	The pathnames you pass to these routines I<should> be absolute. The
292	encoded as octets. The reason for the former is that at the time the	308	reason for this is that at the time the request is being executed, the
293	request is being executed, the current working directory could have	309	current working directory could have changed. Alternatively, you can
294	changed. Alternatively, you can make sure that you never change the	310	make sure that you never change the current working directory anywhere
295	current working directory anywhere in the program and then use relative	311	in the program and then use relative paths. You can also take advantage
296	paths.	312	of IO::AIOs working directory abstraction, that lets you specify paths
		313	relative to some previously-opened "working directory object" - see the
		314	description of the C<IO::AIO::WD> class later in this document.
297		315
298	To encode pathnames as octets, either make sure you either: a) always pass	316	To encode pathnames as octets, either make sure you either: a) always pass
299	in filenames you got from outside (command line, readdir etc.) without	317	in filenames you got from outside (command line, readdir etc.) without
300	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode	318	tinkering, b) are in your native filesystem encoding, c) use the Encode
301	your pathnames to the locale (or other) encoding in effect in the user	319	module and encode your pathnames to the locale (or other) encoding in
302	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	320	effect in the user environment, d) use Glib::filename_from_unicode on
303	use something else to ensure your scalar has the correct contents.	321	unicode filenames or e) use something else to ensure your scalar has the
		322	correct contents.
304		323
305	This works, btw. independent of the internal UTF-8 bit, which IO::AIO	324	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
306	handles correctly whether it is set or not.	325	handles correctly whether it is set or not.
		326
		327	=head2 AIO REQUEST FUNCTIONS
307		328
308	=over 4	329	=over 4
309		330
310	=item $prev_pri = aioreq_pri [$pri]	331	=item $prev_pri = aioreq_pri [$pri]
311		332
…		…
341		362
342		363
343	=item aio_open $pathname, $flags, $mode, $callback->($fh)	364	=item aio_open $pathname, $flags, $mode, $callback->($fh)
344		365
345	Asynchronously open or create a file and call the callback with a newly	366	Asynchronously open or create a file and call the callback with a newly
346	created filehandle for the file.	367	created filehandle for the file (or C<undef> in case of an error).
347		368
348	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,	369	The pathname passed to C<aio_open> must be absolute. See API NOTES, above,
349	for an explanation.	370	for an explanation.
350		371
351	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a	372	The C<$flags> argument is a bitmask. See the C<Fcntl> module for a
…		…
367	} else {	388	} else {
368	die "open failed: $!\n";	389	die "open failed: $!\n";
369	}	390	}
370	};	391	};
371		392
		393	In addition to all the common open modes/flags (C<O_RDONLY>, C<O_WRONLY>,
		394	C<O_RDWR>, C<O_CREAT>, C<O_TRUNC>, C<O_EXCL> and C<O_APPEND>), the
		395	following POSIX and non-POSIX constants are available (missing ones on
		396	your system are, as usual, C<0>):
		397
		398	C<O_ASYNC>, C<O_DIRECT>, C<O_NOATIME>, C<O_CLOEXEC>, C<O_NOCTTY>, C<O_NOFOLLOW>,
		399	C<O_NONBLOCK>, C<O_EXEC>, C<O_SEARCH>, C<O_DIRECTORY>, C<O_DSYNC>,
		400	C<O_RSYNC>, C<O_SYNC> and C<O_TTY_INIT>.
		401
372		402
373	=item aio_close $fh, $callback->($status)	403	=item aio_close $fh, $callback->($status)
374		404
375	Asynchronously close a file and call the callback with the result	405	Asynchronously close a file and call the callback with the result
376	code.	406	code.
…		…
384		414
385	Or in other words: the file descriptor will be closed, but it will not be	415	Or in other words: the file descriptor will be closed, but it will not be
386	free for reuse until the perl filehandle is closed.	416	free for reuse until the perl filehandle is closed.
387		417
388	=cut	418	=cut
		419
		420	=item aio_seek $fh, $offset, $whence, $callback->($offs)
		421
		422	Seeks the filehandle to the new C<$offset>, similarly to perl's
		423	C<sysseek>. The C<$whence> can use the traditional values (C<0> for
		424	C<IO::AIO::SEEK_SET>, C<1> for C<IO::AIO::SEEK_CUR> or C<2> for
		425	C<IO::AIO::SEEK_END>).
		426
		427	The resulting absolute offset will be passed to the callback, or C<-1> in
		428	case of an error.
		429
		430	In theory, the C<$whence> constants could be different than the
		431	corresponding values from L<Fcntl>, but perl guarantees they are the same,
		432	so don't panic.
		433
		434	As a GNU/Linux (and maybe Solaris) extension, also the constants
		435	C<IO::AIO::SEEK_DATA> and C<IO::AIO::SEEK_HOLE> are available, if they
		436	could be found. No guarantees about suitability for use in C<aio_seek> or
		437	Perl's C<sysseek> can be made though, although I would naively assume they
		438	"just work".
389		439
390	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	440	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
391		441
392	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	442	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
393		443
…		…
426		476
427	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	477	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
428	reading at byte offset C<$in_offset>, and starts writing at the current	478	reading at byte offset C<$in_offset>, and starts writing at the current
429	file offset of C<$out_fh>. Because of that, it is not safe to issue more	479	file offset of C<$out_fh>. Because of that, it is not safe to issue more
430	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each	480	than one C<aio_sendfile> per C<$out_fh>, as they will interfere with each
431	other.	481	other. The same C<$in_fh> works fine though, as this function does not
		482	move or use the file offset of C<$in_fh>.
432		483
433	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than	484	Please note that C<aio_sendfile> can read more bytes from C<$in_fh> than
434	are written, and there is no way to find out how many bytes have been read	485	are written, and there is no way to find out how many more bytes have been
435	from C<aio_sendfile> alone, as C<aio_sendfile> only provides the number of	486	read from C<aio_sendfile> alone, as C<aio_sendfile> only provides the
436	bytes written to C<$out_fh>. Only if the result value equals C<$length>	487	number of bytes written to C<$out_fh>. Only if the result value equals
437	one can assume that C<$length> bytes have been read.	488	C<$length> one can assume that C<$length> bytes have been read.
438		489
439	Unlike with other C<aio_> functions, it makes a lot of sense to use	490	Unlike with other C<aio_> functions, it makes a lot of sense to use
440	C<aio_sendfile> on non-blocking sockets, as long as one end (typically	491	C<aio_sendfile> on non-blocking sockets, as long as one end (typically
441	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while	492	the C<$in_fh>) is a file - the file I/O will then be asynchronous, while
442	the socket I/O will be non-blocking. Note, however, that you can run into	493	the socket I/O will be non-blocking. Note, however, that you can run
443	a trap where C<aio_sendfile> reads some data with readahead, then fails	494	into a trap where C<aio_sendfile> reads some data with readahead, then
444	to write all data, and when the socket is ready the next time, the data	495	fails to write all data, and when the socket is ready the next time, the
445	in the cache is already lost, forcing C<aio_sendfile> to again hit the	496	data in the cache is already lost, forcing C<aio_sendfile> to again hit
446	disk. Explicit C<aio_read> + C<aio_write> let's you control resource usage	497	the disk. Explicit C<aio_read> + C<aio_write> let's you better control
447	much better.	498	resource usage.
448		499
449	This call tries to make use of a native C<sendfile> syscall to provide	500	This call tries to make use of a native C<sendfile>-like syscall to
450	zero-copy operation. For this to work, C<$out_fh> should refer to a	501	provide zero-copy operation. For this to work, C<$out_fh> should refer to
451	socket, and C<$in_fh> should refer to an mmap'able file.	502	a socket, and C<$in_fh> should refer to an mmap'able file.
452		503
453	If a native sendfile cannot be found or it fails with C<ENOSYS>,	504	If a native sendfile cannot be found or it fails with C<ENOSYS>,
454	C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or C<ENOTSOCK>,	505	C<EINVAL>, C<ENOTSUP>, C<EOPNOTSUPP>, C<EAFNOSUPPORT>, C<EPROTOTYPE> or
455	it will be emulated, so you can call C<aio_sendfile> on any type of	506	C<ENOTSOCK>, it will be emulated, so you can call C<aio_sendfile> on any
456	filehandle regardless of the limitations of the operating system.	507	type of filehandle regardless of the limitations of the operating system.
		508
		509	As native sendfile syscalls (as practically any non-POSIX interface hacked
		510	together in a hurry to improve benchmark numbers) tend to be rather buggy
		511	on many systems, this implementation tries to work around some known bugs
		512	in Linux and FreeBSD kernels (probably others, too), but that might fail,
		513	so you really really should check the return value of C<aio_sendfile> -
		514	fewre bytes than expected might have been transferred.
457		515
458		516
459	=item aio_readahead $fh,$offset,$length, $callback->($retval)	517	=item aio_readahead $fh,$offset,$length, $callback->($retval)
460		518
461	C<aio_readahead> populates the page cache with data from a file so that	519	C<aio_readahead> populates the page cache with data from a file so that
…		…
545	namemax => 255,	603	namemax => 255,
546	frsize => 1024,	604	frsize => 1024,
547	fsid => 1810	605	fsid => 1810
548	}	606	}
549		607
		608	Here is a (likely partial) list of fsid values used by Linux - it is safe
		609	to 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
550		689
551	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)	690	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
552		691
553	Works like perl's C<utime> function (including the special case of $atime	692	Works like perl's C<utime> function (including the special case of $atime
554	and $mtime being undef). Fractional times are supported if the underlying	693	and $mtime being undef). Fractional times are supported if the underlying
…		…
582	=item aio_truncate $fh_or_path, $offset, $callback->($status)	721	=item aio_truncate $fh_or_path, $offset, $callback->($status)
583		722
584	Works like truncate(2) or ftruncate(2).	723	Works like truncate(2) or ftruncate(2).
585		724
586		725
		726	=item aio_allocate $fh, $mode, $offset, $len, $callback->($status)
		727
		728	Allocates or freed disk space according to the C<$mode> argument. See the
		729	linux C<fallocate> docuemntation for details.
		730
		731	C<$mode> can currently be C<0> or C<IO::AIO::FALLOC_FL_KEEP_SIZE>
		732	to allocate space, or C<IO::AIO::FALLOC_FL_PUNCH_HOLE \|
		733	IO::AIO::FALLOC_FL_KEEP_SIZE>, to deallocate a file range.
		734
		735	The file system block size used by C<fallocate> is presumably the
		736	C<f_bsize> returned by C<statvfs>.
		737
		738	If C<fallocate> isn't available or cannot be emulated (currently no
		739	emulation will be attempted), passes C<-1> and sets C<$!> to C<ENOSYS>.
		740
		741
587	=item aio_chmod $fh_or_path, $mode, $callback->($status)	742	=item aio_chmod $fh_or_path, $mode, $callback->($status)
588		743
589	Works like perl's C<chmod> function.	744	Works like perl's C<chmod> function.
590		745
591		746
…		…
593		748
594	Asynchronously unlink (delete) a file and call the callback with the	749	Asynchronously unlink (delete) a file and call the callback with the
595	result code.	750	result code.
596		751
597		752
598	=item aio_mknod $path, $mode, $dev, $callback->($status)	753	=item aio_mknod $pathname, $mode, $dev, $callback->($status)
599		754
600	[EXPERIMENTAL]	755	[EXPERIMENTAL]
601		756
602	Asynchronously create a device node (or fifo). See mknod(2).	757	Asynchronously create a device node (or fifo). See mknod(2).
603		758
604	The only (POSIX-) portable way of calling this function is:	759	The only (POSIX-) portable way of calling this function is:
605		760
606	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...	761	aio_mknod $pathname, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
607		762
608	See C<aio_stat> for info about some potentially helpful extra constants	763	See C<aio_stat> for info about some potentially helpful extra constants
609	and functions.	764	and functions.
610		765
611	=item aio_link $srcpath, $dstpath, $callback->($status)	766	=item aio_link $srcpath, $dstpath, $callback->($status)
…		…
618		773
619	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	774	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
620	the path C<$dstpath> and call the callback with the result code.	775	the path C<$dstpath> and call the callback with the result code.
621		776
622		777
623	=item aio_readlink $path, $callback->($link)	778	=item aio_readlink $pathname, $callback->($link)
624		779
625	Asynchronously read the symlink specified by C<$path> and pass it to	780	Asynchronously read the symlink specified by C<$path> and pass it to
626	the callback. If an error occurs, nothing or undef gets passed to the	781	the callback. If an error occurs, nothing or undef gets passed to the
627	callback.	782	callback.
628		783
629		784
		785	=item aio_realpath $pathname, $callback->($path)
		786
		787	Asynchronously make the path absolute and resolve any symlinks in
		788	C<$path>. The resulting path only consists of directories (same as
		789	L<Cwd::realpath>).
		790
		791	This request can be used to get the absolute path of the current working
		792	directory by passing it a path of F<.> (a single dot).
		793
		794
630	=item aio_rename $srcpath, $dstpath, $callback->($status)	795	=item aio_rename $srcpath, $dstpath, $callback->($status)
631		796
632	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	797	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
633	rename(2) and call the callback with the result code.	798	rename(2) and call the callback with the result code.
634		799
…		…
656	array-ref with the filenames.	821	array-ref with the filenames.
657		822
658		823
659	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)	824	=item aio_readdirx $pathname, $flags, $callback->($entries, $flags)
660		825
661	Quite similar to C<aio_readdir>, but the C<$flags> argument allows to tune	826	Quite similar to C<aio_readdir>, but the C<$flags> argument allows one to
662	behaviour and output format. In case of an error, C<$entries> will be	827	tune behaviour and output format. In case of an error, C<$entries> will be
663	C<undef>.	828	C<undef>.
664		829
665	The flags are a combination of the following constants, ORed together (the	830	The flags are a combination of the following constants, ORed together (the
666	flags will also be passed to the callback, possibly modified):	831	flags will also be passed to the callback, possibly modified):
667		832
668	=over 4	833	=over 4
669		834
670	=item IO::AIO::READDIR_DENTS	835	=item IO::AIO::READDIR_DENTS
671		836
672	When this flag is off, then the callback gets an arrayref with of names	837	When this flag is off, then the callback gets an arrayref consisting of
673	only (as with C<aio_readdir>), otherwise it gets an arrayref with	838	names only (as with C<aio_readdir>), otherwise it gets an arrayref with
674	C<[$name, $type, $inode]> arrayrefs, each describing a single directory	839	C<[$name, $type, $inode]> arrayrefs, each describing a single directory
675	entry in more detail.	840	entry in more detail.
676		841
677	C<$name> is the name of the entry.	842	C<$name> is the name of the entry.
678		843
…		…
691	systems that do not deliver the inode information.	856	systems that do not deliver the inode information.
692		857
693	=item IO::AIO::READDIR_DIRS_FIRST	858	=item IO::AIO::READDIR_DIRS_FIRST
694		859
695	When this flag is set, then the names will be returned in an order where	860	When this flag is set, then the names will be returned in an order where
696	likely directories come first. This is useful when you need to quickly	861	likely directories come first, in optimal stat order. This is useful when
697	find directories, or you want to find all directories while avoiding to	862	you need to quickly find directories, or you want to find all directories
698	stat() each entry.	863	while avoiding to stat() each entry.
699		864
700	If the system returns type information in readdir, then this is used	865	If the system returns type information in readdir, then this is used
701	to find directories directly. Otherwise, likely directories are files	866	to find directories directly. Otherwise, likely directories are names
702	beginning with ".", or otherwise files with no dots, of which files with	867	beginning with ".", or otherwise names with no dots, of which names with
703	short names are tried first.	868	short names are tried first.
704		869
705	=item IO::AIO::READDIR_STAT_ORDER	870	=item IO::AIO::READDIR_STAT_ORDER
706		871
707	When this flag is set, then the names will be returned in an order	872	When this flag is set, then the names will be returned in an order
…		…
714		879
715	=item IO::AIO::READDIR_FOUND_UNKNOWN	880	=item IO::AIO::READDIR_FOUND_UNKNOWN
716		881
717	This flag should not be set when calling C<aio_readdirx>. Instead, it	882	This flag should not be set when calling C<aio_readdirx>. Instead, it
718	is being set by C<aio_readdirx>, when any of the C<$type>'s found were	883	is being set by C<aio_readdirx>, when any of the C<$type>'s found were
719	C<IO::AIO::DT_UNKNOWN>. The absense of this flag therefore indicates that all	884	C<IO::AIO::DT_UNKNOWN>. The absence of this flag therefore indicates that all
720	C<$type>'s are known, which can be used to speed up some algorithms.	885	C<$type>'s are known, which can be used to speed up some algorithms.
721		886
722	=back	887	=back
723		888
724		889
725	=item aio_load $path, $data, $callback->($status)	890	=item aio_load $pathname, $data, $callback->($status)
726		891
727	This is a composite request that tries to fully load the given file into	892	This is a composite request that tries to fully load the given file into
728	memory. Status is the same as with aio_read.	893	memory. Status is the same as with aio_read.
729		894
730	=cut	895	=cut
…		…
852	if ($_[0] && $! == EXDEV) {	1017	if ($_[0] && $! == EXDEV) {
853	aioreq_pri $pri;	1018	aioreq_pri $pri;
854	add $grp aio_copy $src, $dst, sub {	1019	add $grp aio_copy $src, $dst, sub {
855	$grp->result ($_[0]);	1020	$grp->result ($_[0]);
856		1021
857	if (!$_[0]) {	1022	unless ($_[0]) {
858	aioreq_pri $pri;	1023	aioreq_pri $pri;
859	add $grp aio_unlink $src;	1024	add $grp aio_unlink $src;
860	}	1025	}
861	};	1026	};
862	} else {	1027	} else {
…		…
865	};	1030	};
866		1031
867	$grp	1032	$grp
868	}	1033	}
869		1034
870	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	1035	=item aio_scandir $pathname, $maxreq, $callback->($dirs, $nondirs)
871		1036
872	Scans a directory (similar to C<aio_readdir>) but additionally tries to	1037	Scans a directory (similar to C<aio_readdir>) but additionally tries to
873	efficiently separate the entries of directory C<$path> into two sets of	1038	efficiently separate the entries of directory C<$path> into two sets of
874	names, directories you can recurse into (directories), and ones you cannot	1039	names, directories you can recurse into (directories), and ones you cannot
875	recurse into (everything else, including symlinks to directories).	1040	recurse into (everything else, including symlinks to directories).
…		…
906	Then entries will be sorted into likely directories a non-initial dot	1071	Then entries will be sorted into likely directories a non-initial dot
907	currently) and likely non-directories (see C<aio_readdirx>). Then every	1072	currently) and likely non-directories (see C<aio_readdirx>). Then every
908	entry plus an appended C</.> will be C<stat>'ed, likely directories first,	1073	entry plus an appended C</.> will be C<stat>'ed, likely directories first,
909	in order of their inode numbers. If that succeeds, it assumes that the	1074	in order of their inode numbers. If that succeeds, it assumes that the
910	entry is a directory or a symlink to directory (which will be checked	1075	entry is a directory or a symlink to directory (which will be checked
911	seperately). This is often faster than stat'ing the entry itself because	1076	separately). This is often faster than stat'ing the entry itself because
912	filesystems might detect the type of the entry without reading the inode	1077	filesystems might detect the type of the entry without reading the inode
913	data (e.g. ext2fs filetype feature), even on systems that cannot return	1078	data (e.g. ext2fs filetype feature), even on systems that cannot return
914	the filetype information on readdir.	1079	the filetype information on readdir.
915		1080
916	If the known number of directories (link count - 2) has been reached, the	1081	If the known number of directories (link count - 2) has been reached, the
…		…
932		1097
933	my $grp = aio_group $cb;	1098	my $grp = aio_group $cb;
934		1099
935	$maxreq = 4 if $maxreq <= 0;	1100	$maxreq = 4 if $maxreq <= 0;
936		1101
937	# stat once	1102	# get a wd object
938	aioreq_pri $pri;	1103	aioreq_pri $pri;
939	add $grp aio_stat $path, sub {	1104	add $grp aio_wd $path, sub {
		1105	$_[0]
940	return $grp->result () if $_[0];	1106	or return $grp->result ();
941	my $now = time;
942	my $hash1 = join ":", (stat _)[0,1,3,7,9];
943		1107
944	# read the directory entries	1108	my $wd = [shift, "."];
		1109
		1110	# stat once
945	aioreq_pri $pri;	1111	aioreq_pri $pri;
946	add $grp aio_readdirx $path, READDIR_DIRS_FIRST, sub {	1112	add $grp aio_stat $wd, sub {
947	my $entries = shift
948	or return $grp->result ();	1113	return $grp->result () if $_[0];
		1114	my $now = time;
		1115	my $hash1 = join ":", (stat _)[0,1,3,7,9];
949		1116
950	# stat the dir another time	1117	# read the directory entries
951	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;
952	add $grp aio_stat $path, sub {	1125	add $grp aio_stat $wd, sub {
953	my $hash2 = join ":", (stat _)[0,1,3,7,9];	1126	my $hash2 = join ":", (stat _)[0,1,3,7,9];
954		1127
955	my $ndirs;	1128	my $ndirs;
956		1129
957	# take the slow route if anything looks fishy	1130	# take the slow route if anything looks fishy
958	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	1131	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
959	$ndirs = -1;	1132	$ndirs = -1;
960	} else {	1133	} else {
961	# if nlink == 2, we are finished	1134	# if nlink == 2, we are finished
962	# for non-posix-fs's, we rely on nlink < 2	1135	# for non-posix-fs's, we rely on nlink < 2
963	$ndirs = (stat _)[3] - 2	1136	$ndirs = (stat _)[3] - 2
964	or return $grp->result ([], $entries);	1137	or return $grp->result ([], $entries);
965	}	1138	}
966		1139
967	my (@dirs, @nondirs);	1140	my (@dirs, @nondirs);
968		1141
969	my $statgrp = add $grp aio_group sub {	1142	my $statgrp = add $grp aio_group sub {
970	$grp->result (\@dirs, \@nondirs);	1143	$grp->result (\@dirs, \@nondirs);
971	};	1144	};
972		1145
973	limit $statgrp $maxreq;	1146	limit $statgrp $maxreq;
974	feed $statgrp sub {	1147	feed $statgrp sub {
975	return unless @$entries;	1148	return unless @$entries;
976	my $entry = shift @$entries;	1149	my $entry = shift @$entries;
977		1150
978	aioreq_pri $pri;	1151	aioreq_pri $pri;
		1152	$wd->[1] = "$entry/.";
979	add $statgrp aio_stat "$path/$entry/.", sub {	1153	add $statgrp aio_stat $wd, sub {
980	if ($_[0] < 0) {	1154	if ($_[0] < 0) {
981	push @nondirs, $entry;	1155	push @nondirs, $entry;
982	} else {	1156	} else {
983	# need to check for real directory	1157	# need to check for real directory
984	aioreq_pri $pri;	1158	aioreq_pri $pri;
		1159	$wd->[1] = $entry;
985	add $statgrp aio_lstat "$path/$entry", sub {	1160	add $statgrp aio_lstat $wd, sub {
986	if (-d _) {	1161	if (-d _) {
987	push @dirs, $entry;	1162	push @dirs, $entry;
988		1163
989	unless (--$ndirs) {	1164	unless (--$ndirs) {
990	push @nondirs, @$entries;	1165	push @nondirs, @$entries;
991	feed $statgrp;	1166	feed $statgrp;
		1167	}
		1168	} else {
		1169	push @nondirs, $entry;
992	}	1170	}
993	} else {
994	push @nondirs, $entry;
995	}	1171	}
996	}	1172	}
997	}	1173	};
998	};	1174	};
999	};	1175	};
1000	};	1176	};
1001	};	1177	};
1002	};	1178	};
1003		1179
1004	$grp	1180	$grp
1005	}	1181	}
1006		1182
1007	=item aio_rmtree $path, $callback->($status)	1183	=item aio_rmtree $pathname, $callback->($status)
1008		1184
1009	Delete a directory tree starting (and including) C<$path>, return the	1185	Delete a directory tree starting (and including) C<$path>, return the
1010	status of the final C<rmdir> only. This is a composite request that	1186	status of the final C<rmdir> only. This is a composite request that
1011	uses C<aio_scandir> to recurse into and rmdir directories, and unlink	1187	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
1012	everything else.	1188	everything else.
1013		1189
1014	=cut	1190	=cut
1015		1191
…		…
1054	callback with the fdatasync result code.	1230	callback with the fdatasync result code.
1055		1231
1056	If this call isn't available because your OS lacks it or it couldn't be	1232	If this call isn't available because your OS lacks it or it couldn't be
1057	detected, it will be emulated by calling C<fsync> instead.	1233	detected, it will be emulated by calling C<fsync> instead.
1058		1234
		1235	=item aio_syncfs $fh, $callback->($status)
		1236
		1237	Asynchronously call the syncfs syscall to sync the filesystem associated
		1238	to the given filehandle and call the callback with the syncfs result
		1239	code. If syncfs is not available, calls sync(), but returns C<-1> and sets
		1240	errno to C<ENOSYS> nevertheless.
		1241
1059	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)	1242	=item aio_sync_file_range $fh, $offset, $nbytes, $flags, $callback->($status)
1060		1243
1061	Sync the data portion of the file specified by C<$offset> and C<$length>	1244	Sync the data portion of the file specified by C<$offset> and C<$length>
1062	to disk (but NOT the metadata), by calling the Linux-specific	1245	to disk (but NOT the metadata), by calling the Linux-specific
1063	sync_file_range call. If sync_file_range is not available or it returns	1246	sync_file_range call. If sync_file_range is not available or it returns
…		…
1066	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,	1249	C<$flags> can be a combination of C<IO::AIO::SYNC_FILE_RANGE_WAIT_BEFORE>,
1067	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and	1250	C<IO::AIO::SYNC_FILE_RANGE_WRITE> and
1068	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range	1251	C<IO::AIO::SYNC_FILE_RANGE_WAIT_AFTER>: refer to the sync_file_range
1069	manpage for details.	1252	manpage for details.
1070		1253
1071	=item aio_pathsync $path, $callback->($status)	1254	=item aio_pathsync $pathname, $callback->($status)
1072		1255
1073	This request tries to open, fsync and close the given path. This is a	1256	This request tries to open, fsync and close the given path. This is a
1074	composite request intended to sync directories after directory operations	1257	composite request intended to sync directories after directory operations
1075	(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
1076	specific effect, but usually it makes sure that directory changes get	1259	specific effect, but usually it makes sure that directory changes get
…		…
1128		1311
1129	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1312	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
1130	scalars.	1313	scalars.
1131		1314
1132	It touches (reads or writes) all memory pages in the specified	1315	It touches (reads or writes) all memory pages in the specified
1133	range inside the scalar. All caveats and parameters are the same	1316	range inside the scalar. All caveats and parameters are the same
1134	as for C<aio_msync>, above, except for flags, which must be either	1317	as for C<aio_msync>, above, except for flags, which must be either
1135	C<0> (which reads all pages and ensures they are instantiated) or	1318	C<0> (which reads all pages and ensures they are instantiated) or
1136	C<IO::AIO::MT_MODIFY>, which modifies the memory page s(by reading and	1319	C<IO::AIO::MT_MODIFY>, which modifies the memory pages (by reading and
1137	writing an octet from it, which dirties the page).	1320	writing an octet from it, which dirties the page).
1138		1321
1139	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)	1322	=item aio_mlock $scalar, $offset = 0, $length = undef, $callback->($status)
1140		1323
1141	This is a rather advanced IO::AIO call, which works best on mmap(2)ed	1324	This is a rather advanced IO::AIO call, which works best on mmap(2)ed
…		…
1172	documented under L<MISCELLANEOUS FUNCTIONS>.	1355	documented under L<MISCELLANEOUS FUNCTIONS>.
1173		1356
1174	Example: asynchronously lock all current and future pages into memory.	1357	Example: asynchronously lock all current and future pages into memory.
1175		1358
1176	aio_mlockall IO::AIO::MCL_FUTURE;	1359	aio_mlockall IO::AIO::MCL_FUTURE;
		1360
		1361	=item aio_fiemap $fh, $start, $length, $flags, $count, $cb->(\@extents)
		1362
		1363	Queries the extents of the given file (by calling the Linux C<FIEMAP>
		1364	ioctl, see L<http://cvs.schmorp.de/IO-AIO/doc/fiemap.txt> for details). If
		1365	the ioctl is not available on your OS, then this request will fail with
		1366	C<ENOSYS>.
		1367
		1368	C<$start> is the starting offset to query extents for, C<$length> is the
		1369	size of the range to query - if it is C<undef>, then the whole file will
		1370	be queried.
		1371
		1372	C<$flags> is a combination of flags (C<IO::AIO::FIEMAP_FLAG_SYNC> or
		1373	C<IO::AIO::FIEMAP_FLAG_XATTR> - C<IO::AIO::FIEMAP_FLAGS_COMPAT> is also
		1374	exported), and is normally C<0> or C<IO::AIO::FIEMAP_FLAG_SYNC> to query
		1375	the data portion.
		1376
		1377	C<$count> is the maximum number of extent records to return. If it is
		1378	C<undef>, then IO::AIO queries all extents of the range. As a very special
		1379	case, if it is C<0>, then the callback receives the number of extents
		1380	instead of the extents themselves (which is unreliable, see below).
		1381
		1382	If an error occurs, the callback receives no arguments. The special
		1383	C<errno> value C<IO::AIO::EBADR> is available to test for flag errors.
		1384
		1385	Otherwise, the callback receives an array reference with extent
		1386	structures. Each extent structure is an array reference itself, with the
		1387	following members:
		1388
		1389	[$logical, $physical, $length, $flags]
		1390
		1391	Flags is any combination of the following flag values (typically either C<0>
		1392	or C<IO::AIO::FIEMAP_EXTENT_LAST> (1)):
		1393
		1394	C<IO::AIO::FIEMAP_EXTENT_LAST>, C<IO::AIO::FIEMAP_EXTENT_UNKNOWN>,
		1395	C<IO::AIO::FIEMAP_EXTENT_DELALLOC>, C<IO::AIO::FIEMAP_EXTENT_ENCODED>,
		1396	C<IO::AIO::FIEMAP_EXTENT_DATA_ENCRYPTED>, C<IO::AIO::FIEMAP_EXTENT_NOT_ALIGNED>,
		1397	C<IO::AIO::FIEMAP_EXTENT_DATA_INLINE>, C<IO::AIO::FIEMAP_EXTENT_DATA_TAIL>,
		1398	C<IO::AIO::FIEMAP_EXTENT_UNWRITTEN>, C<IO::AIO::FIEMAP_EXTENT_MERGED> or
		1399	C<IO::AIO::FIEMAP_EXTENT_SHARED>.
		1400
		1401	At the time of this writing (Linux 3.2), this requets is unreliable unless
		1402	C<$count> is C<undef>, as the kernel has all sorts of bugs preventing
		1403	it to return all extents of a range for files with large number of
		1404	extents. The code works around all these issues if C<$count> is undef.
1177		1405
1178	=item aio_group $callback->(...)	1406	=item aio_group $callback->(...)
1179		1407
1180	This is a very special aio request: Instead of doing something, it is a	1408	This is a very special aio request: Instead of doing something, it is a
1181	container for other aio requests, which is useful if you want to bundle	1409	container for other aio requests, which is useful if you want to bundle
…		…
1218	like sleep and file handle readable/writable, the overhead this creates is	1446	like sleep and file handle readable/writable, the overhead this creates is
1219	immense (it blocks a thread for a long time) so do not use this function	1447	immense (it blocks a thread for a long time) so do not use this function
1220	except to put your application under artificial I/O pressure.	1448	except to put your application under artificial I/O pressure.
1221		1449
1222	=back	1450	=back
		1451
		1452
		1453	=head2 IO::AIO::WD - multiple working directories
		1454
		1455	Your process only has one current working directory, which is used by all
		1456	threads. This makes it hard to use relative paths (some other component
		1457	could call C<chdir> at any time, and it is hard to control when the path
		1458	will be used by IO::AIO).
		1459
		1460	One solution for this is to always use absolute paths. This usually works,
		1461	but can be quite slow (the kernel has to walk the whole path on every
		1462	access), and can also be a hassle to implement.
		1463
		1464	Newer POSIX systems have a number of functions (openat, fdopendir,
		1465	futimensat and so on) that make it possible to specify working directories
		1466	per operation.
		1467
		1468	For portability, and because the clowns who "designed", or shall I write,
		1469	perpetrated this new interface were obviously half-drunk, this abstraction
		1470	cannot be perfect, though.
		1471
		1472	IO::AIO allows you to convert directory paths into a so-called IO::AIO::WD
		1473	object. This object stores the canonicalised, absolute version of the
		1474	path, and on systems that allow it, also a directory file descriptor.
		1475
		1476	Everywhere where a pathname is accepted by IO::AIO (e.g. in C<aio_stat>
		1477	or C<aio_unlink>), one can specify an array reference with an IO::AIO::WD
		1478	object and a pathname instead (or the IO::AIO::WD object alone, which
		1479	gets interpreted as C<[$wd, "."]>). If the pathname is absolute, the
		1480	IO::AIO::WD object is ignored, otherwise the pathname is resolved relative
		1481	to that IO::AIO::WD object.
		1482
		1483	For example, to get a wd object for F</etc> and then stat F<passwd>
		1484	inside, 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
		1498	That C<aio_wd> is a request and not a normal function shows that creating
		1499	an IO::AIO::WD object is itself a potentially blocking operation, which is
		1500	why it is done asynchronously.
		1501
		1502	To stat the directory obtained with C<aio_wd> above, one could write
		1503	either 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 $wd , sub { ... # shorthand for the previous
		1508
		1509	As with normal pathnames, IO::AIO keeps a copy of the working directory
		1510	object and the pathname string, so you could write the following without
		1511	causing any issues due to C<$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
		1522	There are some caveats: when directories get renamed (or deleted), the
		1523	pathname string doesn't change, so will point to the new directory (or
		1524	nowhere at all), while the directory fd, if available on the system,
		1525	will still point to the original directory. Most functions accepting a
		1526	pathname will use the directory fd on newer systems, and the string on
		1527	older systems. Some functions (such as realpath) will always rely on the
		1528	string form of the pathname.
		1529
		1530	So this functionality is mainly useful to get some protection against
		1531	C<chdir>, to easily get an absolute path out of a relative path for future
		1532	reference, and to speed up doing many operations in the same directory
		1533	(e.g. when stat'ing all files in a directory).
		1534
		1535	The following functions implement this working directory abstraction:
		1536
		1537	=over 4
		1538
		1539	=item aio_wd $pathname, $callback->($wd)
		1540
		1541	Asynchonously canonicalise the given pathname and convert it to an
		1542	IO::AIO::WD object representing it. If possible and supported on the
		1543	system, also open a directory fd to speed up pathname resolution relative
		1544	to this working directory.
		1545
		1546	If something goes wrong, then C<undef> is passwd to the callback instead
		1547	of a working directory object and C<$!> is set appropriately. Since
		1548	passing C<undef> as working directory component of a pathname fails the
		1549	request with C<ENOENT>, there is often no need for error checking in the
		1550	C<aio_wd> callback, as future requests using the value will fail in the
		1551	expected way.
		1552
		1553	If this call isn't available because your OS lacks it or it couldn't be
		1554	detected, it will be emulated by calling C<fsync> instead.
		1555
		1556	=item IO::AIO::CWD
		1557
		1558	This is a compiletime constant (object) that represents the process
		1559	current working directory.
		1560
		1561	Specifying this object as working directory object for a pathname is as if
		1562	the pathname would be specified directly, without a directory object. For
		1563	example, these calls are functionally identical:
		1564
		1565	aio_stat "somefile", sub { ... };
		1566	aio_stat [IO::AIO::CWD, "somefile"], sub { ... };
		1567
		1568	=back
		1569
		1570	To recover the path associated with an IO::AIO::WD object, you can use
		1571	C<aio_realpath>:
		1572
		1573	aio_realpath $wd, sub {
		1574	warn "path is $_[0]\n";
		1575	};
		1576
1223		1577
1224	=head2 IO::AIO::REQ CLASS	1578	=head2 IO::AIO::REQ CLASS
1225		1579
1226	All non-aggregate C<aio_*> functions return an object of this class when	1580	All non-aggregate C<aio_*> functions return an object of this class when
1227	called in non-void context.	1581	called in non-void context.
…		…
1345		1699
1346	Sets a feeder/generator on this group: every group can have an attached	1700	Sets a feeder/generator on this group: every group can have an attached
1347	generator that generates requests if idle. The idea behind this is that,	1701	generator that generates requests if idle. The idea behind this is that,
1348	although you could just queue as many requests as you want in a group,	1702	although you could just queue as many requests as you want in a group,
1349	this might starve other requests for a potentially long time. For example,	1703	this might starve other requests for a potentially long time. For example,
1350	C<aio_scandir> might generate hundreds of thousands C<aio_stat> requests,	1704	C<aio_scandir> might generate hundreds of thousands of C<aio_stat>
1351	delaying any later requests for a long time.	1705	requests, delaying any later requests for a long time.
1352		1706
1353	To avoid this, and allow incremental generation of requests, you can	1707	To avoid this, and allow incremental generation of requests, you can
1354	instead a group and set a feeder on it that generates those requests. The	1708	instead a group and set a feeder on it that generates those requests. The
1355	feed callback will be called whenever there are few enough (see C<limit>,	1709	feed callback will be called whenever there are few enough (see C<limit>,
1356	below) requests active in the group itself and is expected to queue more	1710	below) requests active in the group itself and is expected to queue more
…		…
1405		1759
1406	See C<poll_cb> for an example.	1760	See C<poll_cb> for an example.
1407		1761
1408	=item IO::AIO::poll_cb	1762	=item IO::AIO::poll_cb
1409		1763
1410	Process some outstanding events on the result pipe. You have to call this	1764	Process some requests that have reached the result phase (i.e. they have
1411	regularly. Returns C<0> if all events could be processed, or C<-1> if it	1765	been executed but the results are not yet reported). You have to call
1412	returned earlier for whatever reason. Returns immediately when no events	1766	this "regularly" to finish outstanding requests.
1413	are outstanding. The amount of events processed depends on the settings of
1414	C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
1415		1767
		1768	Returns C<0> if all events could be processed (or there were no
		1769	events to process), or C<-1> if it returned earlier for whatever
		1770	reason. Returns immediately when no events are outstanding. The amount
		1771	of events processed depends on the settings of C<IO::AIO::max_poll_req>,
		1772	C<IO::AIO::max_poll_time> and C<IO::AIO::max_outstanding>.
		1773
1416	If not all requests were processed for whatever reason, the filehandle	1774	If not all requests were processed for whatever reason, the poll file
1417	will still be ready when C<poll_cb> returns, so normally you don't have to	1775	descriptor will still be ready when C<poll_cb> returns, so normally you
1418	do anything special to have it called later.	1776	don't have to do anything special to have it called later.
		1777
		1778	Apart from calling C<IO::AIO::poll_cb> when the event filehandle becomes
		1779	ready, it can be beneficial to call this function from loops which submit
		1780	a lot of requests, to make sure the results get processed when they become
		1781	available and not just when the loop is finished and the event loop takes
		1782	over again. This function returns very fast when there are no outstanding
		1783	requests.
1419		1784
1420	Example: Install an Event watcher that automatically calls	1785	Example: Install an Event watcher that automatically calls
1421	IO::AIO::poll_cb with high priority (more examples can be found in the	1786	IO::AIO::poll_cb with high priority (more examples can be found in the
1422	SYNOPSIS section, at the top of this document):	1787	SYNOPSIS section, at the top of this document):
1423		1788
…		…
1425	poll => 'r', async => 1,	1790	poll => 'r', async => 1,
1426	cb => \&IO::AIO::poll_cb);	1791	cb => \&IO::AIO::poll_cb);
1427		1792
1428	=item IO::AIO::poll_wait	1793	=item IO::AIO::poll_wait
1429		1794
1430	If there are any outstanding requests and none of them in the result	1795	Wait until either at least one request is in the result phase or no
1431	phase, wait till the result filehandle becomes ready for reading (simply	1796	requests are outstanding anymore.
1432	does a C<select> on the filehandle. This is useful if you want to	1797
1433	synchronously wait for some requests to finish).	1798	This is useful if you want to synchronously wait for some requests to
		1799	become ready, without actually handling them.
1434		1800
1435	See C<nreqs> for an example.	1801	See C<nreqs> for an example.
1436		1802
1437	=item IO::AIO::poll	1803	=item IO::AIO::poll
1438		1804
…		…
1525		1891
1526	Under normal circumstances you don't need to call this function.	1892	Under normal circumstances you don't need to call this function.
1527		1893
1528	=item IO::AIO::max_idle $nthreads	1894	=item IO::AIO::max_idle $nthreads
1529		1895
1530	Limit the number of threads (default: 4) that are allowed to idle (i.e.,	1896	Limit the number of threads (default: 4) that are allowed to idle
1531	threads that did not get a request to process within 10 seconds). That	1897	(i.e., threads that did not get a request to process within the idle
1532	means if a thread becomes idle while C<$nthreads> other threads are also	1898	timeout (default: 10 seconds). That means if a thread becomes idle while
1533	idle, it will free its resources and exit.	1899	C<$nthreads> other threads are also idle, it will free its resources and
		1900	exit.
1534		1901
1535	This is useful when you allow a large number of threads (e.g. 100 or 1000)	1902	This is useful when you allow a large number of threads (e.g. 100 or 1000)
1536	to allow for extremely high load situations, but want to free resources	1903	to allow for extremely high load situations, but want to free resources
1537	under normal circumstances (1000 threads can easily consume 30MB of RAM).	1904	under normal circumstances (1000 threads can easily consume 30MB of RAM).
1538		1905
1539	The default is probably ok in most situations, especially if thread	1906	The default is probably ok in most situations, especially if thread
1540	creation is fast. If thread creation is very slow on your system you might	1907	creation is fast. If thread creation is very slow on your system you might
1541	want to use larger values.	1908	want to use larger values.
1542		1909
		1910	=item IO::AIO::idle_timeout $seconds
		1911
		1912	Sets the minimum idle timeout (default 10) after which worker threads are
		1913	allowed to exit. SEe C<IO::AIO::max_idle>.
		1914
1543	=item IO::AIO::max_outstanding $maxreqs	1915	=item IO::AIO::max_outstanding $maxreqs
		1916
		1917	Sets the maximum number of outstanding requests to C<$nreqs>. If
		1918	you do queue up more than this number of requests, the next call to
		1919	C<IO::AIO::poll_cb> (and other functions calling C<poll_cb>, such as
		1920	C<IO::AIO::flush> or C<IO::AIO::poll>) will block until the limit is no
		1921	longer exceeded.
		1922
		1923	In other words, this setting does not enforce a queue limit, but can be
		1924	used to make poll functions block if the limit is exceeded.
1544		1925
1545	This is a very bad function to use in interactive programs because it	1926	This is a very bad function to use in interactive programs because it
1546	blocks, and a bad way to reduce concurrency because it is inexact: Better	1927	blocks, and a bad way to reduce concurrency because it is inexact: Better
1547	use an C<aio_group> together with a feed callback.	1928	use an C<aio_group> together with a feed callback.
1548		1929
1549	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1930	It's main use is in scripts without an event loop - when you want to stat
1550	do queue up more than this number of requests, the next call to the	1931	a lot of files, you can write somehting like this:
1551	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
1552	function will block until the limit is no longer exceeded.
1553		1932
1554	The default value is very large, so there is no practical limit on the	1933	IO::AIO::max_outstanding 32;
1555	number of outstanding requests.
1556		1934
1557	You can still queue as many requests as you want. Therefore,	1935	for my $path (...) {
1558	C<max_outstanding> is mainly useful in simple scripts (with low values) or	1936	aio_stat $path , ...;
1559	as a stop gap to shield against fatal memory overflow (with large values).	1937	IO::AIO::poll_cb;
		1938	}
		1939
		1940	IO::AIO::flush;
		1941
		1942	The call to C<poll_cb> inside the loop will normally return instantly, but
		1943	as soon as more thna C<32> reqeusts are in-flight, it will block until
		1944	some requests have been handled. This keeps the loop from pushing a large
		1945	number of C<aio_stat> requests onto the queue.
		1946
		1947	The default value for C<max_outstanding> is very large, so there is no
		1948	practical limit on the number of outstanding requests.
1560		1949
1561	=back	1950	=back
1562		1951
1563	=head3 STATISTICAL INFORMATION	1952	=head3 STATISTICAL INFORMATION
1564		1953
…		…
1604		1993
1605	=item IO::AIO::fadvise $fh, $offset, $len, $advice	1994	=item IO::AIO::fadvise $fh, $offset, $len, $advice
1606		1995
1607	Simply calls the C<posix_fadvise> function (see its	1996	Simply calls the C<posix_fadvise> function (see its
1608	manpage for details). The following advice constants are	1997	manpage for details). The following advice constants are
1609	avaiable: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,	1998	available: C<IO::AIO::FADV_NORMAL>, C<IO::AIO::FADV_SEQUENTIAL>,
1610	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,	1999	C<IO::AIO::FADV_RANDOM>, C<IO::AIO::FADV_NOREUSE>,
1611	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.	2000	C<IO::AIO::FADV_WILLNEED>, C<IO::AIO::FADV_DONTNEED>.
1612		2001
1613	On systems that do not implement C<posix_fadvise>, this function returns	2002	On systems that do not implement C<posix_fadvise>, this function returns
1614	ENOSYS, otherwise the return value of C<posix_fadvise>.	2003	ENOSYS, otherwise the return value of C<posix_fadvise>.
1615		2004
1616	=item IO::AIO::madvise $scalar, $offset, $len, $advice	2005	=item IO::AIO::madvise $scalar, $offset, $len, $advice
1617		2006
1618	Simply calls the C<posix_madvise> function (see its	2007	Simply calls the C<posix_madvise> function (see its
1619	manpage for details). The following advice constants are	2008	manpage for details). The following advice constants are
1620	avaiable: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,	2009	available: C<IO::AIO::MADV_NORMAL>, C<IO::AIO::MADV_SEQUENTIAL>,
1621	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.	2010	C<IO::AIO::MADV_RANDOM>, C<IO::AIO::MADV_WILLNEED>, C<IO::AIO::MADV_DONTNEED>.
1622		2011
1623	On systems that do not implement C<posix_madvise>, this function returns	2012	On systems that do not implement C<posix_madvise>, this function returns
1624	ENOSYS, otherwise the return value of C<posix_madvise>.	2013	ENOSYS, otherwise the return value of C<posix_madvise>.
1625		2014
1626	=item IO::AIO::mprotect $scalar, $offset, $len, $protect	2015	=item IO::AIO::mprotect $scalar, $offset, $len, $protect
1627		2016
1628	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed	2017	Simply calls the C<mprotect> function on the preferably AIO::mmap'ed
1629	$scalar (see its manpage for details). The following protect	2018	$scalar (see its manpage for details). The following protect
1630	constants are avaiable: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,	2019	constants are available: C<IO::AIO::PROT_NONE>, C<IO::AIO::PROT_READ>,
1631	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.	2020	C<IO::AIO::PROT_WRITE>, C<IO::AIO::PROT_EXEC>.
1632		2021
1633	On systems that do not implement C<mprotect>, this function returns	2022	On systems that do not implement C<mprotect>, this function returns
1634	ENOSYS, otherwise the return value of C<mprotect>.	2023	ENOSYS, otherwise the return value of C<mprotect>.
1635		2024
1636	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]	2025	=item IO::AIO::mmap $scalar, $length, $prot, $flags, $fh[, $offset]
1637		2026
1638	Memory-maps a file (or anonymous memory range) and attaches it to the	2027	Memory-maps a file (or anonymous memory range) and attaches it to the
1639	given C<$scalar>, which will act like a string scalar.	2028	given C<$scalar>, which will act like a string scalar. Returns true on
		2029	success, and false otherwise.
1640		2030
1641	The only operations allowed on the scalar are C<substr>/C<vec> that don't	2031	The only operations allowed on the scalar are C<substr>/C<vec> that don't
1642	change the string length, and most read-only operations such as copying it	2032	change the string length, and most read-only operations such as copying it
1643	or searching it with regexes and so on.	2033	or searching it with regexes and so on.
1644		2034
…		…
1697	Calls the C<munlockall> function.	2087	Calls the C<munlockall> function.
1698		2088
1699	On systems that do not implement C<munlockall>, this function returns	2089	On systems that do not implement C<munlockall>, this function returns
1700	ENOSYS, otherwise the return value of C<munlockall>.	2090	ENOSYS, otherwise the return value of C<munlockall>.
1701		2091
		2092	=item IO::AIO::splice $r_fh, $r_off, $w_fh, $w_off, $length, $flags
		2093
		2094	Calls the GNU/Linux C<splice(2)> syscall, if available. If C<$r_off> or
		2095	C<$w_off> are C<undef>, then C<NULL> is passed for these, otherwise they
		2096	should be the file offset.
		2097
		2098	C<$r_fh> and C<$w_fh> should not refer to the same file, as splice might
		2099	silently corrupt the data in this case.
		2100
		2101	The following symbol flag values are available: C<IO::AIO::SPLICE_F_MOVE>,
		2102	C<IO::AIO::SPLICE_F_NONBLOCK>, C<IO::AIO::SPLICE_F_MORE> and
		2103	C<IO::AIO::SPLICE_F_GIFT>.
		2104
		2105	See the C<splice(2)> manpage for details.
		2106
		2107	=item IO::AIO::tee $r_fh, $w_fh, $length, $flags
		2108
		2109	Calls the GNU/Linux C<tee(2)> syscall, see it's manpage and the
		2110	description for C<IO::AIO::splice> above for details.
		2111
1702	=back	2112	=back
1703		2113
1704	=cut	2114	=cut
1705		2115
1706	min_parallel 8;	2116	min_parallel 8;
…		…
1740	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>	2150	Danga::Socket->AddOtherFds (IO::AIO::poll_fileno =>
1741	\&IO::AIO::poll_cb);	2151	\&IO::AIO::poll_cb);
1742		2152
1743	=head2 FORK BEHAVIOUR	2153	=head2 FORK BEHAVIOUR
1744		2154
1745	This module should do "the right thing" when the process using it forks:	2155	Usage of pthreads in a program changes the semantics of fork
		2156	considerably. Specifically, only async-safe functions can be called after
		2157	fork. Perl doesn't know about this, so in general, you cannot call fork
		2158	with defined behaviour in perl if pthreads are involved. IO::AIO uses
		2159	pthreads, so this applies, but many other extensions and (for inexplicable
		2160	reasons) perl itself often is linked against pthreads, so this limitation
		2161	applies to quite a lot of perls.
1746		2162
1747	Before the fork, IO::AIO enters a quiescent state where no requests	2163	This module no longer tries to fight your OS, or POSIX. That means IO::AIO
1748	can be added in other threads and no results will be processed. After	2164	only works in the process that loaded it. Forking is fully supported, but
1749	the fork the parent simply leaves the quiescent state and continues	2165	using IO::AIO in the child is not.
1750	request/result processing, while the child frees the request/result queue
1751	(so that the requests started before the fork will only be handled in the
1752	parent). Threads will be started on demand until the limit set in the
1753	parent process has been reached again.
1754		2166
1755	In short: the parent will, after a short pause, continue as if fork had	2167	You might get around by not I<using> IO::AIO before (or after)
1756	not been called, while the child will act as if IO::AIO has not been used	2168	forking. You could also try to call the L<IO::AIO::reinit> function in the
1757	yet.	2169	child:
		2170
		2171	=over 4
		2172
		2173	=item IO::AIO::reinit
		2174
		2175	Abandons all current requests and I/O threads and simply reinitialises all
		2176	data structures. This is not an operation supported by any standards, but
		2177	happens to work on GNU/Linux and some newer BSD systems.
		2178
		2179	The only reasonable use for this function is to call it after forking, if
		2180	C<IO::AIO> was used in the parent. Calling it while IO::AIO is active in
		2181	the process will result in undefined behaviour. Calling it at any time
		2182	will also result in any undefined (by POSIX) behaviour.
		2183
		2184	=back
1758		2185
1759	=head2 MEMORY USAGE	2186	=head2 MEMORY USAGE
1760		2187
1761	Per-request usage:	2188	Per-request usage:
1762		2189

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.187 by root, Fri Feb 11 00:05:17 2011 UTC vs. Revision 1.240 by root, Mon Dec 17 06:18:39 2012 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.187 by root, Fri Feb 11 00:05:17 2011 UTC vs.
Revision 1.240 by root, Mon Dec 17 06:18:39 2012 UTC