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

Comparing IO-AIO/AIO.pm (file contents):
Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC vs.
Revision 1.117 by root, Sat Oct 6 14:05:19 2007 UTC

…		…
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use IO::AIO;	7	use IO::AIO;
8		8
9	aio_open "/etc/passwd", O_RDONLY, 0, sub {	9	aio_open "/etc/passwd", O_RDONLY, 0, sub {
10	my ($fh) = @_;	10	my $fh = shift
		11	or die "/etc/passwd: $!";
11	...	12	...
12	};	13	};
13		14
14	aio_unlink "/tmp/file", sub { };	15	aio_unlink "/tmp/file", sub { };
15		16
…		…
50		51
51	=head1 DESCRIPTION	52	=head1 DESCRIPTION
52		53
53	This module implements asynchronous I/O using whatever means your	54	This module implements asynchronous I/O using whatever means your
54	operating system supports.	55	operating system supports.
		56
		57	Asynchronous means that operations that can normally block your program
		58	(e.g. reading from disk) will be done asynchronously: the operation
		59	will still block, but you can do something else in the meantime. This
		60	is extremely useful for programs that need to stay interactive even
		61	when doing heavy I/O (GUI programs, high performance network servers
		62	etc.), but can also be used to easily do operations in parallel that are
		63	normally done sequentially, e.g. stat'ing many files, which is much faster
		64	on a RAID volume or over NFS when you do a number of stat operations
		65	concurrently.
		66
		67	While most of this works on all types of file descriptors (for
		68	example sockets), using these functions on file descriptors that
		69	support nonblocking operation (again, sockets, pipes etc.) is very
		70	inefficient. Use an event loop for that (such as the L<Event\|Event>
		71	module): IO::AIO will naturally fit into such an event loop itself.
55		72
56	In this version, a number of threads are started that execute your	73	In this version, a number of threads are started that execute your
57	requests and signal their completion. You don't need thread support	74	requests and signal their completion. You don't need thread support
58	in perl, and the threads created by this module will not be visible	75	in perl, and the threads created by this module will not be visible
59	to perl. In the future, this module might make use of the native aio	76	to perl. In the future, this module might make use of the native aio
60	functions available on many operating systems. However, they are often	77	functions available on many operating systems. However, they are often
61	not well-supported or restricted (Linux doesn't allow them on normal	78	not well-supported or restricted (GNU/Linux doesn't allow them on normal
62	files currently, for example), and they would only support aio_read and	79	files currently, for example), and they would only support aio_read and
63	aio_write, so the remaining functionality would have to be implemented	80	aio_write, so the remaining functionality would have to be implemented
64	using threads anyway.	81	using threads anyway.
65		82
66	Although the module will work with in the presence of other (Perl-)	83	Although the module will work in the presence of other (Perl-) threads,
67	threads, it is currently not reentrant in any way, so use appropriate	84	it is currently not reentrant in any way, so use appropriate locking
68	locking yourself, always call C<poll_cb> from within the same thread, or	85	yourself, always call C<poll_cb> from within the same thread, or never
69	never call C<poll_cb> (or other C<aio_> functions) recursively.	86	call C<poll_cb> (or other C<aio_> functions) recursively.
		87
		88	=head2 EXAMPLE
		89
		90	This is a simple example that uses the Event module and loads
		91	F</etc/passwd> asynchronously:
		92
		93	use Fcntl;
		94	use Event;
		95	use IO::AIO;
		96
		97	# register the IO::AIO callback with Event
		98	Event->io (fd => IO::AIO::poll_fileno,
		99	poll => 'r',
		100	cb => \&IO::AIO::poll_cb);
		101
		102	# queue the request to open /etc/passwd
		103	aio_open "/etc/passwd", O_RDONLY, 0, sub {
		104	my $fh = shift
		105	or die "error while opening: $!";
		106
		107	# stat'ing filehandles is generally non-blocking
		108	my $size = -s $fh;
		109
		110	# queue a request to read the file
		111	my $contents;
		112	aio_read $fh, 0, $size, $contents, 0, sub {
		113	$_[0] == $size
		114	or die "short read: $!";
		115
		116	close $fh;
		117
		118	# file contents now in $contents
		119	print $contents;
		120
		121	# exit event loop and program
		122	Event::unloop;
		123	};
		124	};
		125
		126	# possibly queue up other requests, or open GUI windows,
		127	# check for sockets etc. etc.
		128
		129	# process events as long as there are some:
		130	Event::loop;
70		131
71	=head1 REQUEST ANATOMY AND LIFETIME	132	=head1 REQUEST ANATOMY AND LIFETIME
72		133
73	Every C<aio_*> function creates a request. which is a C data structure not	134	Every C<aio_*> function creates a request. which is a C data structure not
74	directly visible to Perl.	135	directly visible to Perl.
…		…
116	Request has reached the end of its lifetime and holds no resources anymore	177	Request has reached the end of its lifetime and holds no resources anymore
117	(except possibly for the Perl object, but its connection to the actual	178	(except possibly for the Perl object, but its connection to the actual
118	aio request is severed and calling its methods will either do nothing or	179	aio request is severed and calling its methods will either do nothing or
119	result in a runtime error).	180	result in a runtime error).
120		181
		182	=back
		183
121	=cut	184	=cut
122		185
123	package IO::AIO;	186	package IO::AIO;
		187
		188	use Carp ();
124		189
125	no warnings;	190	no warnings;
126	use strict 'vars';	191	use strict 'vars';
127		192
128	use base 'Exporter';	193	use base 'Exporter';
129		194
130	BEGIN {	195	BEGIN {
131	our $VERSION = '2.0';	196	our $VERSION = '2.51';
132		197
133	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat	198	our @AIO_REQ = qw(aio_sendfile aio_read aio_write aio_open aio_close aio_stat
134	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink	199	aio_lstat aio_unlink aio_rmdir aio_readdir aio_scandir aio_symlink
135	aio_fsync aio_fdatasync aio_readahead aio_rename aio_link aio_move	200	aio_readlink aio_fsync aio_fdatasync aio_readahead aio_rename aio_link
136	aio_copy aio_group aio_nop aio_mknod);	201	aio_move aio_copy aio_group aio_nop aio_mknod aio_load aio_rmtree aio_mkdir
		202	aio_chown aio_chmod aio_utime aio_truncate);
137	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice));	203	our @EXPORT = (@AIO_REQ, qw(aioreq_pri aioreq_nice aio_block));
138	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	204	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush
139	min_parallel max_parallel nreqs nready npending);	205	min_parallel max_parallel max_idle
		206	nreqs nready npending nthreads
		207	max_poll_time max_poll_reqs);
140		208
141	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';	209	@IO::AIO::GRP::ISA = 'IO::AIO::REQ';
142		210
143	require XSLoader;	211	require XSLoader;
144	XSLoader::load ("IO::AIO", $VERSION);	212	XSLoader::load ("IO::AIO", $VERSION);
145	}	213	}
146		214
147	=head1 FUNCTIONS	215	=head1 FUNCTIONS
148		216
149	=head2 AIO FUNCTIONS	217	=head2 AIO REQUEST FUNCTIONS
150		218
151	All the C<aio_*> calls are more or less thin wrappers around the syscall	219	All the C<aio_*> calls are more or less thin wrappers around the syscall
152	with the same name (sans C<aio_>). The arguments are similar or identical,	220	with the same name (sans C<aio_>). The arguments are similar or identical,
153	and they all accept an additional (and optional) C<$callback> argument	221	and they all accept an additional (and optional) C<$callback> argument
154	which must be a code reference. This code reference will get called with	222	which must be a code reference. This code reference will get called with
…		…
157	syscall has been executed asynchronously.	225	syscall has been executed asynchronously.
158		226
159	All functions expecting a filehandle keep a copy of the filehandle	227	All functions expecting a filehandle keep a copy of the filehandle
160	internally until the request has finished.	228	internally until the request has finished.
161		229
162	All requests return objects of type L<IO::AIO::REQ> that allow further	230	All functions return request objects of type L<IO::AIO::REQ> that allow
163	manipulation of those requests while they are in-flight.	231	further manipulation of those requests while they are in-flight.
164		232
165	The pathnames you pass to these routines I<must> be absolute and	233	The pathnames you pass to these routines I<must> be absolute and
166	encoded in byte form. The reason for the former is that at the time the	234	encoded as octets. The reason for the former is that at the time the
167	request is being executed, the current working directory could have	235	request is being executed, the current working directory could have
168	changed. Alternatively, you can make sure that you never change the	236	changed. Alternatively, you can make sure that you never change the
169	current working directory.	237	current working directory anywhere in the program and then use relative
		238	paths.
170		239
171	To encode pathnames to byte form, either make sure you either: a)	240	To encode pathnames as octets, either make sure you either: a) always pass
172	always pass in filenames you got from outside (command line, readdir	241	in filenames you got from outside (command line, readdir etc.) without
173	etc.), b) are ASCII or ISO 8859-1, c) use the Encode module and encode	242	tinkering, b) are ASCII or ISO 8859-1, c) use the Encode module and encode
174	your pathnames to the locale (or other) encoding in effect in the user	243	your pathnames to the locale (or other) encoding in effect in the user
175	environment, d) use Glib::filename_from_unicode on unicode filenames or e)	244	environment, d) use Glib::filename_from_unicode on unicode filenames or e)
176	use something else.	245	use something else to ensure your scalar has the correct contents.
		246
		247	This works, btw. independent of the internal UTF-8 bit, which IO::AIO
		248	handles correctly wether it is set or not.
177		249
178	=over 4	250	=over 4
179		251
180	=item $prev_pri = aioreq_pri [$pri]	252	=item $prev_pri = aioreq_pri [$pri]
181		253
…		…
201	aio_read $_[0], ..., sub {	273	aio_read $_[0], ..., sub {
202	...	274	...
203	};	275	};
204	};	276	};
205		277
		278
206	=item aioreq_nice $pri_adjust	279	=item aioreq_nice $pri_adjust
207		280
208	Similar to C<aioreq_pri>, but subtracts the given value from the current	281	Similar to C<aioreq_pri>, but subtracts the given value from the current
209	priority, so effects are cumulative.	282	priority, so the effect is cumulative.
		283
210		284
211	=item aio_open $pathname, $flags, $mode, $callback->($fh)	285	=item aio_open $pathname, $flags, $mode, $callback->($fh)
212		286
213	Asynchronously open or create a file and call the callback with a newly	287	Asynchronously open or create a file and call the callback with a newly
214	created filehandle for the file.	288	created filehandle for the file.
…		…
220	list. They are the same as used by C<sysopen>.	294	list. They are the same as used by C<sysopen>.
221		295
222	Likewise, C<$mode> specifies the mode of the newly created file, if it	296	Likewise, C<$mode> specifies the mode of the newly created file, if it
223	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,	297	didn't exist and C<O_CREAT> has been given, just like perl's C<sysopen>,
224	except that it is mandatory (i.e. use C<0> if you don't create new files,	298	except that it is mandatory (i.e. use C<0> if you don't create new files,
225	and C<0666> or C<0777> if you do).	299	and C<0666> or C<0777> if you do). Note that the C<$mode> will be modified
		300	by the umask in effect then the request is being executed, so better never
		301	change the umask.
226		302
227	Example:	303	Example:
228		304
229	aio_open "/etc/passwd", O_RDONLY, 0, sub {	305	aio_open "/etc/passwd", O_RDONLY, 0, sub {
230	if ($_[0]) {	306	if ($_[0]) {
…		…
233	} else {	309	} else {
234	die "open failed: $!\n";	310	die "open failed: $!\n";
235	}	311	}
236	};	312	};
237		313
		314
238	=item aio_close $fh, $callback->($status)	315	=item aio_close $fh, $callback->($status)
239		316
240	Asynchronously close a file and call the callback with the result	317	Asynchronously close a file and call the callback with the result
241	code. I<WARNING:> although accepted, you should not pass in a perl	318	code.
242	filehandle here, as perl will likely close the file descriptor another
243	time when the filehandle is destroyed. Normally, you can safely call perls
244	C<close> or just let filehandles go out of scope.
245		319
246	This is supposed to be a bug in the API, so that might change. It's	320	Unfortunately, you can't do this to perl. Perl I<insists> very strongly on
247	therefore best to avoid this function.	321	closing the file descriptor associated with the filehandle itself. Here is
		322	what aio_close will try:
		323
		324	1. dup()licate the fd
		325	2. asynchronously close() the duplicated fd
		326	3. dup()licate the fd once more
		327	4. let perl close() the filehandle
		328	5. asynchronously close the duplicated fd
		329
		330	The idea is that the first close() flushes stuff to disk that closing an
		331	fd will flush, so when perl closes the fd, nothing much will need to be
		332	flushed. The second async. close() will then flush stuff to disk that
		333	closing the last fd to the file will flush.
		334
		335	Just FYI, SuSv3 has this to say on close:
		336
		337	All outstanding record locks owned by the process on the file
		338	associated with the file descriptor shall be removed.
		339
		340	If fildes refers to a socket, close() shall cause the socket to be
		341	destroyed. ... close() shall block for up to the current linger
		342	interval until all data is transmitted.
		343	[this actually sounds like a specification bug, but who knows]
		344
		345	And at least Linux additionally actually flushes stuff on every close,
		346	even when the file itself is still open.
		347
		348	Sounds enourmously inefficient and complicated? Yes... please show me how
		349	to nuke perl's fd out of existence...
		350
		351	=cut
		352
		353	sub aio_close($;$) {
		354	aio_block {
		355	my ($fh, $cb) = @_;
		356
		357	my $pri = aioreq_pri;
		358	my $grp = aio_group $cb;
		359
		360	my $fd = fileno $fh;
		361
		362	defined $fd or Carp::croak "aio_close called with fd-less filehandle";
		363
		364	# if the dups fail we will simply get EBADF
		365	my $fd2 = _dup $fd;
		366	aioreq_pri $pri;
		367	add $grp _aio_close $fd2, sub {
		368	my $fd2 = _dup $fd;
		369	close $fh;
		370	aioreq_pri $pri;
		371	add $grp _aio_close $fd2, sub {
		372	$grp->result ($_[0]);
		373	};
		374	};
		375
		376	$grp
		377	}
		378	}
		379
248		380
249	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	381	=item aio_read $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
250		382
251	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)	383	=item aio_write $fh,$offset,$length, $data,$dataoffset, $callback->($retval)
252		384
253	Reads or writes C<length> bytes from the specified C<fh> and C<offset>	385	Reads or writes C<$length> bytes from the specified C<$fh> and C<$offset>
254	into the scalar given by C<data> and offset C<dataoffset> and calls the	386	into the scalar given by C<$data> and offset C<$dataoffset> and calls the
255	callback without the actual number of bytes read (or -1 on error, just	387	callback without the actual number of bytes read (or -1 on error, just
256	like the syscall).	388	like the syscall).
257		389
		390	If C<$offset> is undefined, then the current file descriptor offset will
		391	be used (and updated), otherwise the file descriptor offset will not be
		392	changed by these calls.
		393
		394	If C<$length> is undefined in C<aio_write>, use the remaining length of C<$data>.
		395
		396	If C<$dataoffset> is less than zero, it will be counted from the end of
		397	C<$data>.
		398
258	The C<$data> scalar I<MUST NOT> be modified in any way while the request	399	The C<$data> scalar I<MUST NOT> be modified in any way while the request
259	is outstanding. Modifying it can result in segfaults or WW3 (if the	400	is outstanding. Modifying it can result in segfaults or World War III (if
260	necessary/optional hardware is installed).	401	the necessary/optional hardware is installed).
261		402
262	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at	403	Example: Read 15 bytes at offset 7 into scalar C<$buffer>, starting at
263	offset C<0> within the scalar:	404	offset C<0> within the scalar:
264		405
265	aio_read $fh, 7, 15, $buffer, 0, sub {	406	aio_read $fh, 7, 15, $buffer, 0, sub {
266	$_[0] > 0 or die "read error: $!";	407	$_[0] > 0 or die "read error: $!";
267	print "read $_[0] bytes: <$buffer>\n";	408	print "read $_[0] bytes: <$buffer>\n";
268	};	409	};
		410
269		411
270	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)	412	=item aio_sendfile $out_fh, $in_fh, $in_offset, $length, $callback->($retval)
271		413
272	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts	414	Tries to copy C<$length> bytes from C<$in_fh> to C<$out_fh>. It starts
273	reading at byte offset C<$in_offset>, and starts writing at the current	415	reading at byte offset C<$in_offset>, and starts writing at the current
…		…
287	C<$in_fh> than are written, and there is no way to find out how many	429	C<$in_fh> than are written, and there is no way to find out how many
288	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only	430	bytes have been read from C<aio_sendfile> alone, as C<aio_sendfile> only
289	provides the number of bytes written to C<$out_fh>. Only if the result	431	provides the number of bytes written to C<$out_fh>. Only if the result
290	value equals C<$length> one can assume that C<$length> bytes have been	432	value equals C<$length> one can assume that C<$length> bytes have been
291	read.	433	read.
		434
292		435
293	=item aio_readahead $fh,$offset,$length, $callback->($retval)	436	=item aio_readahead $fh,$offset,$length, $callback->($retval)
294		437
295	C<aio_readahead> populates the page cache with data from a file so that	438	C<aio_readahead> populates the page cache with data from a file so that
296	subsequent reads from that file will not block on disk I/O. The C<$offset>	439	subsequent reads from that file will not block on disk I/O. The C<$offset>
…		…
302	file. The current file offset of the file is left unchanged.	445	file. The current file offset of the file is left unchanged.
303		446
304	If that syscall doesn't exist (likely if your OS isn't Linux) it will be	447	If that syscall doesn't exist (likely if your OS isn't Linux) it will be
305	emulated by simply reading the data, which would have a similar effect.	448	emulated by simply reading the data, which would have a similar effect.
306		449
		450
307	=item aio_stat $fh_or_path, $callback->($status)	451	=item aio_stat $fh_or_path, $callback->($status)
308		452
309	=item aio_lstat $fh, $callback->($status)	453	=item aio_lstat $fh, $callback->($status)
310		454
311	Works like perl's C<stat> or C<lstat> in void context. The callback will	455	Works like perl's C<stat> or C<lstat> in void context. The callback will
…		…
324	aio_stat "/etc/passwd", sub {	468	aio_stat "/etc/passwd", sub {
325	$_[0] and die "stat failed: $!";	469	$_[0] and die "stat failed: $!";
326	print "size is ", -s _, "\n";	470	print "size is ", -s _, "\n";
327	};	471	};
328		472
		473
		474	=item aio_utime $fh_or_path, $atime, $mtime, $callback->($status)
		475
		476	Works like perl's C<utime> function (including the special case of $atime
		477	and $mtime being undef). Fractional times are supported if the underlying
		478	syscalls support them.
		479
		480	When called with a pathname, uses utimes(2) if available, otherwise
		481	utime(2). If called on a file descriptor, uses futimes(2) if available,
		482	otherwise returns ENOSYS, so this is not portable.
		483
		484	Examples:
		485
		486	# set atime and mtime to current time (basically touch(1)):
		487	aio_utime "path", undef, undef;
		488	# set atime to current time and mtime to beginning of the epoch:
		489	aio_utime "path", time, undef; # undef==0
		490
		491
		492	=item aio_chown $fh_or_path, $uid, $gid, $callback->($status)
		493
		494	Works like perl's C<chown> function, except that C<undef> for either $uid
		495	or $gid is being interpreted as "do not change" (but -1 can also be used).
		496
		497	Examples:
		498
		499	# same as "chown root path" in the shell:
		500	aio_chown "path", 0, -1;
		501	# same as above:
		502	aio_chown "path", 0, undef;
		503
		504
		505	=item aio_truncate $fh_or_path, $offset, $callback->($status)
		506
		507	Works like truncate(2) or ftruncate(2).
		508
		509
		510	=item aio_chmod $fh_or_path, $mode, $callback->($status)
		511
		512	Works like perl's C<chmod> function.
		513
		514
329	=item aio_unlink $pathname, $callback->($status)	515	=item aio_unlink $pathname, $callback->($status)
330		516
331	Asynchronously unlink (delete) a file and call the callback with the	517	Asynchronously unlink (delete) a file and call the callback with the
332	result code.	518	result code.
333		519
		520
334	=item aio_mknod $path, $mode, $dev, $callback->($status)	521	=item aio_mknod $path, $mode, $dev, $callback->($status)
335		522
		523	[EXPERIMENTAL]
		524
336	Asynchronously create a device node (or fifo). See mknod(2): the only	525	Asynchronously create a device node (or fifo). See mknod(2).
337	portable value for C<$mode> is C<S_IFIFO> ored with permissions, and C<0>	526
338	for C<$dev>.	527	The only (POSIX-) portable way of calling this function is:
		528
		529	aio_mknod $path, IO::AIO::S_IFIFO \| $mode, 0, sub { ...
		530
339		531
340	=item aio_link $srcpath, $dstpath, $callback->($status)	532	=item aio_link $srcpath, $dstpath, $callback->($status)
341		533
342	Asynchronously create a new link to the existing object at C<$srcpath> at	534	Asynchronously create a new link to the existing object at C<$srcpath> at
343	the path C<$dstpath> and call the callback with the result code.	535	the path C<$dstpath> and call the callback with the result code.
344		536
		537
345	=item aio_symlink $srcpath, $dstpath, $callback->($status)	538	=item aio_symlink $srcpath, $dstpath, $callback->($status)
346		539
347	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at	540	Asynchronously create a new symbolic link to the existing object at C<$srcpath> at
348	the path C<$dstpath> and call the callback with the result code.	541	the path C<$dstpath> and call the callback with the result code.
349		542
		543
		544	=item aio_readlink $path, $callback->($link)
		545
		546	Asynchronously read the symlink specified by C<$path> and pass it to
		547	the callback. If an error occurs, nothing or undef gets passed to the
		548	callback.
		549
		550
350	=item aio_rename $srcpath, $dstpath, $callback->($status)	551	=item aio_rename $srcpath, $dstpath, $callback->($status)
351		552
352	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as	553	Asynchronously rename the object at C<$srcpath> to C<$dstpath>, just as
353	rename(2) and call the callback with the result code.	554	rename(2) and call the callback with the result code.
354		555
		556
		557	=item aio_mkdir $pathname, $mode, $callback->($status)
		558
		559	Asynchronously mkdir (create) a directory and call the callback with
		560	the result code. C<$mode> will be modified by the umask at the time the
		561	request is executed, so do not change your umask.
		562
		563
355	=item aio_rmdir $pathname, $callback->($status)	564	=item aio_rmdir $pathname, $callback->($status)
356		565
357	Asynchronously rmdir (delete) a directory and call the callback with the	566	Asynchronously rmdir (delete) a directory and call the callback with the
358	result code.	567	result code.
		568
359		569
360	=item aio_readdir $pathname, $callback->($entries)	570	=item aio_readdir $pathname, $callback->($entries)
361		571
362	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire	572	Unlike the POSIX call of the same name, C<aio_readdir> reads an entire
363	directory (i.e. opendir + readdir + closedir). The entries will not be	573	directory (i.e. opendir + readdir + closedir). The entries will not be
364	sorted, and will B<NOT> include the C<.> and C<..> entries.	574	sorted, and will B<NOT> include the C<.> and C<..> entries.
365		575
366	The callback a single argument which is either C<undef> or an array-ref	576	The callback a single argument which is either C<undef> or an array-ref
367	with the filenames.	577	with the filenames.
		578
		579
		580	=item aio_load $path, $data, $callback->($status)
		581
		582	This is a composite request that tries to fully load the given file into
		583	memory. Status is the same as with aio_read.
		584
		585	=cut
		586
		587	sub aio_load($$;$) {
		588	aio_block {
		589	my ($path, undef, $cb) = @_;
		590	my $data = \$_[1];
		591
		592	my $pri = aioreq_pri;
		593	my $grp = aio_group $cb;
		594
		595	aioreq_pri $pri;
		596	add $grp aio_open $path, O_RDONLY, 0, sub {
		597	my $fh = shift
		598	or return $grp->result (-1);
		599
		600	aioreq_pri $pri;
		601	add $grp aio_read $fh, 0, (-s $fh), $$data, 0, sub {
		602	$grp->result ($_[0]);
		603	};
		604	};
		605
		606	$grp
		607	}
		608	}
368		609
369	=item aio_copy $srcpath, $dstpath, $callback->($status)	610	=item aio_copy $srcpath, $dstpath, $callback->($status)
370		611
371	Try to copy the I<file> (directories not supported as either source or	612	Try to copy the I<file> (directories not supported as either source or
372	destination) from C<$srcpath> to C<$dstpath> and call the callback with	613	destination) from C<$srcpath> to C<$dstpath> and call the callback with
…		…
382	errors are being ignored.	623	errors are being ignored.
383		624
384	=cut	625	=cut
385		626
386	sub aio_copy($$;$) {	627	sub aio_copy($$;$) {
		628	aio_block {
387	my ($src, $dst, $cb) = @_;	629	my ($src, $dst, $cb) = @_;
388		630
389	my $pri = aioreq_pri;	631	my $pri = aioreq_pri;
390	my $grp = aio_group $cb;	632	my $grp = aio_group $cb;
391		633
392	aioreq_pri $pri;	634	aioreq_pri $pri;
393	add $grp aio_open $src, O_RDONLY, 0, sub {	635	add $grp aio_open $src, O_RDONLY, 0, sub {
394	if (my $src_fh = $_[0]) {	636	if (my $src_fh = $_[0]) {
395	my @stat = stat $src_fh;	637	my @stat = stat $src_fh;
396		638
397	aioreq_pri $pri;	639	aioreq_pri $pri;
398	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {	640	add $grp aio_open $dst, O_CREAT \| O_WRONLY \| O_TRUNC, 0200, sub {
399	if (my $dst_fh = $_[0]) {	641	if (my $dst_fh = $_[0]) {
400	aioreq_pri $pri;	642	aioreq_pri $pri;
401	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {	643	add $grp aio_sendfile $dst_fh, $src_fh, 0, $stat[7], sub {
402	if ($_[0] == $stat[7]) {	644	if ($_[0] == $stat[7]) {
403	$grp->result (0);	645	$grp->result (0);
404	close $src_fh;	646	close $src_fh;
405		647
406	# those should not normally block. should. should.	648	# those should not normally block. should. should.
407	utime $stat[8], $stat[9], $dst;	649	utime $stat[8], $stat[9], $dst;
408	chmod $stat[2] & 07777, $dst_fh;	650	chmod $stat[2] & 07777, $dst_fh;
409	chown $stat[4], $stat[5], $dst_fh;	651	chown $stat[4], $stat[5], $dst_fh;
410	close $dst_fh;	652	close $dst_fh;
411	} else {	653	} else {
412	$grp->result (-1);	654	$grp->result (-1);
413	close $src_fh;	655	close $src_fh;
414	close $dst_fh;	656	close $dst_fh;
415		657
416	aioreq $pri;	658	aioreq $pri;
417	add $grp aio_unlink $dst;	659	add $grp aio_unlink $dst;
		660	}
418	}	661	};
		662	} else {
		663	$grp->result (-1);
419	};	664	}
420	} else {
421	$grp->result (-1);
422	}	665	},
		666
		667	} else {
		668	$grp->result (-1);
423	},	669	}
424
425	} else {
426	$grp->result (-1);
427	}	670	};
		671
		672	$grp
428	};	673	}
429
430	$grp
431	}	674	}
432		675
433	=item aio_move $srcpath, $dstpath, $callback->($status)	676	=item aio_move $srcpath, $dstpath, $callback->($status)
434		677
435	Try to move the I<file> (directories not supported as either source or	678	Try to move the I<file> (directories not supported as either source or
…		…
441	that is successful, unlinking the C<$srcpath>.	684	that is successful, unlinking the C<$srcpath>.
442		685
443	=cut	686	=cut
444		687
445	sub aio_move($$;$) {	688	sub aio_move($$;$) {
		689	aio_block {
446	my ($src, $dst, $cb) = @_;	690	my ($src, $dst, $cb) = @_;
447		691
448	my $pri = aioreq_pri;	692	my $pri = aioreq_pri;
449	my $grp = aio_group $cb;	693	my $grp = aio_group $cb;
450		694
451	aioreq_pri $pri;	695	aioreq_pri $pri;
452	add $grp aio_rename $src, $dst, sub {	696	add $grp aio_rename $src, $dst, sub {
453	if ($_[0] && $! == EXDEV) {	697	if ($_[0] && $! == EXDEV) {
454	aioreq_pri $pri;	698	aioreq_pri $pri;
455	add $grp aio_copy $src, $dst, sub {	699	add $grp aio_copy $src, $dst, sub {
		700	$grp->result ($_[0]);
		701
		702	if (!$_[0]) {
		703	aioreq_pri $pri;
		704	add $grp aio_unlink $src;
		705	}
		706	};
		707	} else {
456	$grp->result ($_[0]);	708	$grp->result ($_[0]);
457
458	if (!$_[0]) {
459	aioreq_pri $pri;
460	add $grp aio_unlink $src;
461	}
462	};	709	}
463	} else {
464	$grp->result ($_[0]);
465	}	710	};
		711
		712	$grp
466	};	713	}
467
468	$grp
469	}	714	}
470		715
471	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)	716	=item aio_scandir $path, $maxreq, $callback->($dirs, $nondirs)
472		717
473	Scans a directory (similar to C<aio_readdir>) but additionally tries to	718	Scans a directory (similar to C<aio_readdir>) but additionally tries to
…		…
520	as those tend to return 0 or 1 as link counts, which disables the	765	as those tend to return 0 or 1 as link counts, which disables the
521	directory counting heuristic.	766	directory counting heuristic.
522		767
523	=cut	768	=cut
524		769
525	sub aio_scandir($$$) {	770	sub aio_scandir($$;$) {
		771	aio_block {
526	my ($path, $maxreq, $cb) = @_;	772	my ($path, $maxreq, $cb) = @_;
527		773
528	my $pri = aioreq_pri;	774	my $pri = aioreq_pri;
529		775
530	my $grp = aio_group $cb;	776	my $grp = aio_group $cb;
531		777
532	$maxreq = 4 if $maxreq <= 0;	778	$maxreq = 4 if $maxreq <= 0;
533		779
534	# stat once	780	# stat once
535	aioreq_pri $pri;
536	add $grp aio_stat $path, sub {
537	return $grp->result () if $_[0];
538	my $now = time;
539	my $hash1 = join ":", (stat _)[0,1,3,7,9];
540
541	# read the directory entries
542	aioreq_pri $pri;	781	aioreq_pri $pri;
543	add $grp aio_readdir $path, sub {	782	add $grp aio_stat $path, sub {
544	my $entries = shift
545	or return $grp->result ();	783	return $grp->result () if $_[0];
		784	my $now = time;
		785	my $hash1 = join ":", (stat _)[0,1,3,7,9];
546		786
547	# stat the dir another time	787	# read the directory entries
548	aioreq_pri $pri;	788	aioreq_pri $pri;
		789	add $grp aio_readdir $path, sub {
		790	my $entries = shift
		791	or return $grp->result ();
		792
		793	# stat the dir another time
		794	aioreq_pri $pri;
549	add $grp aio_stat $path, sub {	795	add $grp aio_stat $path, sub {
550	my $hash2 = join ":", (stat _)[0,1,3,7,9];	796	my $hash2 = join ":", (stat _)[0,1,3,7,9];
551		797
552	my $ndirs;	798	my $ndirs;
553		799
554	# take the slow route if anything looks fishy	800	# take the slow route if anything looks fishy
555	if ($hash1 ne $hash2 or (stat _)[9] == $now) {	801	if ($hash1 ne $hash2 or (stat _)[9] == $now) {
556	$ndirs = -1;	802	$ndirs = -1;
557	} else {	803	} else {
558	# if nlink == 2, we are finished	804	# if nlink == 2, we are finished
559	# on non-posix-fs's, we rely on nlink < 2	805	# on non-posix-fs's, we rely on nlink < 2
560	$ndirs = (stat _)[3] - 2	806	$ndirs = (stat _)[3] - 2
561	or return $grp->result ([], $entries);	807	or return $grp->result ([], $entries);
562	}	808	}
563		809
564	# sort into likely dirs and likely nondirs	810	# sort into likely dirs and likely nondirs
565	# dirs == files without ".", short entries first	811	# dirs == files without ".", short entries first
566	$entries = [map $_->[0],	812	$entries = [map $_->[0],
567	sort { $b->[1] cmp $a->[1] }	813	sort { $b->[1] cmp $a->[1] }
568	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],	814	map [$_, sprintf "%s%04d", (/.\./ ? "1" : "0"), length],
569	@$entries];	815	@$entries];
570		816
571	my (@dirs, @nondirs);	817	my (@dirs, @nondirs);
572		818
573	my $statgrp = add $grp aio_group sub {	819	my $statgrp = add $grp aio_group sub {
574	$grp->result (\@dirs, \@nondirs);	820	$grp->result (\@dirs, \@nondirs);
575	};	821	};
576		822
577	limit $statgrp $maxreq;	823	limit $statgrp $maxreq;
578	feed $statgrp sub {	824	feed $statgrp sub {
579	return unless @$entries;	825	return unless @$entries;
580	my $entry = pop @$entries;	826	my $entry = pop @$entries;
581		827
582	aioreq_pri $pri;	828	aioreq_pri $pri;
583	add $statgrp aio_stat "$path/$entry/.", sub {	829	add $statgrp aio_stat "$path/$entry/.", sub {
584	if ($_[0] < 0) {	830	if ($_[0] < 0) {
585	push @nondirs, $entry;	831	push @nondirs, $entry;
586	} else {	832	} else {
587	# need to check for real directory	833	# need to check for real directory
588	aioreq_pri $pri;	834	aioreq_pri $pri;
589	add $statgrp aio_lstat "$path/$entry", sub {	835	add $statgrp aio_lstat "$path/$entry", sub {
590	if (-d _) {	836	if (-d _) {
591	push @dirs, $entry;	837	push @dirs, $entry;
592		838
593	unless (--$ndirs) {	839	unless (--$ndirs) {
594	push @nondirs, @$entries;	840	push @nondirs, @$entries;
595	feed $statgrp;	841	feed $statgrp;
		842	}
		843	} else {
		844	push @nondirs, $entry;
596	}	845	}
597	} else {
598	push @nondirs, $entry;
599	}	846	}
600	}	847	}
601	}	848	};
602	};	849	};
603	};	850	};
604	};	851	};
605	};	852	};
		853
		854	$grp
606	};	855	}
		856	}
607		857
		858	=item aio_rmtree $path, $callback->($status)
		859
		860	Delete a directory tree starting (and including) C<$path>, return the
		861	status of the final C<rmdir> only. This is a composite request that
		862	uses C<aio_scandir> to recurse into and rmdir directories, and unlink
		863	everything else.
		864
		865	=cut
		866
		867	sub aio_rmtree;
		868	sub aio_rmtree($;$) {
		869	aio_block {
		870	my ($path, $cb) = @_;
		871
		872	my $pri = aioreq_pri;
		873	my $grp = aio_group $cb;
		874
		875	aioreq_pri $pri;
		876	add $grp aio_scandir $path, 0, sub {
		877	my ($dirs, $nondirs) = @_;
		878
		879	my $dirgrp = aio_group sub {
		880	add $grp aio_rmdir $path, sub {
		881	$grp->result ($_[0]);
		882	};
		883	};
		884
		885	(aioreq_pri $pri), add $dirgrp aio_rmtree "$path/$_" for @$dirs;
		886	(aioreq_pri $pri), add $dirgrp aio_unlink "$path/$_" for @$nondirs;
		887
		888	add $grp $dirgrp;
		889	};
		890
608	$grp	891	$grp
		892	}
609	}	893	}
610		894
611	=item aio_fsync $fh, $callback->($status)	895	=item aio_fsync $fh, $callback->($status)
612		896
613	Asynchronously call fsync on the given filehandle and call the callback	897	Asynchronously call fsync on the given filehandle and call the callback
…		…
827		1111
828	=back	1112	=back
829		1113
830	=head2 SUPPORT FUNCTIONS	1114	=head2 SUPPORT FUNCTIONS
831		1115
		1116	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
		1117
832	=over 4	1118	=over 4
833		1119
834	=item $fileno = IO::AIO::poll_fileno	1120	=item $fileno = IO::AIO::poll_fileno
835		1121
836	Return the I<request result pipe file descriptor>. This filehandle must be	1122	Return the I<request result pipe file descriptor>. This filehandle must be
…		…
840		1126
841	See C<poll_cb> for an example.	1127	See C<poll_cb> for an example.
842		1128
843	=item IO::AIO::poll_cb	1129	=item IO::AIO::poll_cb
844		1130
845	Process all outstanding events on the result pipe. You have to call this	1131	Process some outstanding events on the result pipe. You have to call this
846	regularly. Returns the number of events processed. Returns immediately	1132	regularly. Returns the number of events processed. Returns immediately
847	when no events are outstanding.	1133	when no events are outstanding. The amount of events processed depends on
		1134	the settings of C<IO::AIO::max_poll_req> and C<IO::AIO::max_poll_time>.
848		1135
849	If not all requests were processed for whatever reason, the filehandle	1136	If not all requests were processed for whatever reason, the filehandle
850	will still be ready when C<poll_cb> returns.	1137	will still be ready when C<poll_cb> returns.
851		1138
852	Example: Install an Event watcher that automatically calls	1139	Example: Install an Event watcher that automatically calls
…		…
854		1141
855	Event->io (fd => IO::AIO::poll_fileno,	1142	Event->io (fd => IO::AIO::poll_fileno,
856	poll => 'r', async => 1,	1143	poll => 'r', async => 1,
857	cb => \&IO::AIO::poll_cb);	1144	cb => \&IO::AIO::poll_cb);
858		1145
859	=item IO::AIO::poll_some $max_requests	1146	=item IO::AIO::max_poll_reqs $nreqs
860		1147
861	Similar to C<poll_cb>, but only processes up to C<$max_requests> requests	1148	=item IO::AIO::max_poll_time $seconds
862	at a time.
863		1149
864	Useful if you want to ensure some level of interactiveness when perl is	1150	These set the maximum number of requests (default C<0>, meaning infinity)
865	not fast enough to process all requests in time.	1151	that are being processed by C<IO::AIO::poll_cb> in one call, respectively
		1152	the maximum amount of time (default C<0>, meaning infinity) spent in
		1153	C<IO::AIO::poll_cb> to process requests (more correctly the mininum amount
		1154	of time C<poll_cb> is allowed to use).
		1155
		1156	Setting C<max_poll_time> to a non-zero value creates an overhead of one
		1157	syscall per request processed, which is not normally a problem unless your
		1158	callbacks are really really fast or your OS is really really slow (I am
		1159	not mentioning Solaris here). Using C<max_poll_reqs> incurs no overhead.
		1160
		1161	Setting these is useful if you want to ensure some level of
		1162	interactiveness when perl is not fast enough to process all requests in
		1163	time.
		1164
		1165	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
866		1166
867	Example: Install an Event watcher that automatically calls	1167	Example: Install an Event watcher that automatically calls
868	IO::AIO::poll_some with low priority, to ensure that other parts of the	1168	IO::AIO::poll_cb with low priority, to ensure that other parts of the
869	program get the CPU sometimes even under high AIO load.	1169	program get the CPU sometimes even under high AIO load.
870		1170
		1171	# try not to spend much more than 0.1s in poll_cb
		1172	IO::AIO::max_poll_time 0.1;
		1173
		1174	# use a low priority so other tasks have priority
871	Event->io (fd => IO::AIO::poll_fileno,	1175	Event->io (fd => IO::AIO::poll_fileno,
872	poll => 'r', nice => 1,	1176	poll => 'r', nice => 1,
873	cb => sub { IO::AIO::poll_some 256 });	1177	cb => &IO::AIO::poll_cb);
874		1178
875	=item IO::AIO::poll_wait	1179	=item IO::AIO::poll_wait
876		1180
		1181	If there are any outstanding requests and none of them in the result
877	Wait till the result filehandle becomes ready for reading (simply does a	1182	phase, wait till the result filehandle becomes ready for reading (simply
878	C<select> on the filehandle. This is useful if you want to synchronously wait	1183	does a C<select> on the filehandle. This is useful if you want to
879	for some requests to finish).	1184	synchronously wait for some requests to finish).
880		1185
881	See C<nreqs> for an example.	1186	See C<nreqs> for an example.
882		1187
		1188	=item IO::AIO::poll
		1189
		1190	Waits until some requests have been handled.
		1191
		1192	Returns the number of requests processed, but is otherwise strictly
		1193	equivalent to:
		1194
		1195	IO::AIO::poll_wait, IO::AIO::poll_cb
		1196
883	=item IO::AIO::nreqs	1197	=item IO::AIO::flush
884		1198
885	Returns the number of requests currently in the ready, execute or pending	1199	Wait till all outstanding AIO requests have been handled.
886	states (i.e. for which their callback has not been invoked yet).
887		1200
888	Example: wait till there are no outstanding requests anymore:	1201	Strictly equivalent to:
889		1202
890	IO::AIO::poll_wait, IO::AIO::poll_cb	1203	IO::AIO::poll_wait, IO::AIO::poll_cb
891	while IO::AIO::nreqs;	1204	while IO::AIO::nreqs;
892		1205
893	=item IO::AIO::nready	1206	=back
894		1207
895	Returns the number of requests currently in the ready state (not yet	1208	=head3 CONTROLLING THE NUMBER OF THREADS
896	executed).
897		1209
898	=item IO::AIO::npending	1210	=over
899
900	Returns the number of requests currently in the pending state (executed,
901	but not yet processed by poll_cb).
902
903	=item IO::AIO::flush
904
905	Wait till all outstanding AIO requests have been handled.
906
907	Strictly equivalent to:
908
909	IO::AIO::poll_wait, IO::AIO::poll_cb
910	while IO::AIO::nreqs;
911
912	=item IO::AIO::poll
913
914	Waits until some requests have been handled.
915
916	Strictly equivalent to:
917
918	IO::AIO::poll_wait, IO::AIO::poll_cb
919	if IO::AIO::nreqs;
920		1211
921	=item IO::AIO::min_parallel $nthreads	1212	=item IO::AIO::min_parallel $nthreads
922		1213
923	Set the minimum number of AIO threads to C<$nthreads>. The current	1214	Set the minimum number of AIO threads to C<$nthreads>. The current
924	default is C<8>, which means eight asynchronous operations can execute	1215	default is C<8>, which means eight asynchronous operations can execute
925	concurrently at any one time (the number of outstanding requests,	1216	concurrently at any one time (the number of outstanding requests,
926	however, is unlimited).	1217	however, is unlimited).
927		1218
928	IO::AIO starts threads only on demand, when an AIO request is queued and	1219	IO::AIO starts threads only on demand, when an AIO request is queued and
929	no free thread exists.	1220	no free thread exists. Please note that queueing up a hundred requests can
		1221	create demand for a hundred threads, even if it turns out that everything
		1222	is in the cache and could have been processed faster by a single thread.
930		1223
931	It is recommended to keep the number of threads relatively low, as some	1224	It is recommended to keep the number of threads relatively low, as some
932	Linux kernel versions will scale negatively with the number of threads	1225	Linux kernel versions will scale negatively with the number of threads
933	(higher parallelity => MUCH higher latency). With current Linux 2.6	1226	(higher parallelity => MUCH higher latency). With current Linux 2.6
934	versions, 4-32 threads should be fine.	1227	versions, 4-32 threads should be fine.
…		…
948	This module automatically runs C<max_parallel 0> at program end, to ensure	1241	This module automatically runs C<max_parallel 0> at program end, to ensure
949	that all threads are killed and that there are no outstanding requests.	1242	that all threads are killed and that there are no outstanding requests.
950		1243
951	Under normal circumstances you don't need to call this function.	1244	Under normal circumstances you don't need to call this function.
952		1245
		1246	=item IO::AIO::max_idle $nthreads
		1247
		1248	Limit the number of threads (default: 4) that are allowed to idle (i.e.,
		1249	threads that did not get a request to process within 10 seconds). That
		1250	means if a thread becomes idle while C<$nthreads> other threads are also
		1251	idle, it will free its resources and exit.
		1252
		1253	This is useful when you allow a large number of threads (e.g. 100 or 1000)
		1254	to allow for extremely high load situations, but want to free resources
		1255	under normal circumstances (1000 threads can easily consume 30MB of RAM).
		1256
		1257	The default is probably ok in most situations, especially if thread
		1258	creation is fast. If thread creation is very slow on your system you might
		1259	want to use larger values.
		1260
953	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs	1261	=item $oldmaxreqs = IO::AIO::max_outstanding $maxreqs
954		1262
955	This is a very bad function to use in interactive programs because it	1263	This is a very bad function to use in interactive programs because it
956	blocks, and a bad way to reduce concurrency because it is inexact: Better	1264	blocks, and a bad way to reduce concurrency because it is inexact: Better
957	use an C<aio_group> together with a feed callback.	1265	use an C<aio_group> together with a feed callback.
958		1266
959	Sets the maximum number of outstanding requests to C<$nreqs>. If you	1267	Sets the maximum number of outstanding requests to C<$nreqs>. If you
960	to queue up more than this number of requests, the next call to the	1268	do queue up more than this number of requests, the next call to the
961	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)	1269	C<poll_cb> (and C<poll_some> and other functions calling C<poll_cb>)
962	function will block until the limit is no longer exceeded.	1270	function will block until the limit is no longer exceeded.
963		1271
964	The default value is very large, so there is no practical limit on the	1272	The default value is very large, so there is no practical limit on the
965	number of outstanding requests.	1273	number of outstanding requests.
…		…
968	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	1276	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
969	as a stop gap to shield against fatal memory overflow (with large values).	1277	as a stop gap to shield against fatal memory overflow (with large values).
970		1278
971	=back	1279	=back
972		1280
		1281	=head3 STATISTICAL INFORMATION
		1282
		1283	=over
		1284
		1285	=item IO::AIO::nreqs
		1286
		1287	Returns the number of requests currently in the ready, execute or pending
		1288	states (i.e. for which their callback has not been invoked yet).
		1289
		1290	Example: wait till there are no outstanding requests anymore:
		1291
		1292	IO::AIO::poll_wait, IO::AIO::poll_cb
		1293	while IO::AIO::nreqs;
		1294
		1295	=item IO::AIO::nready
		1296
		1297	Returns the number of requests currently in the ready state (not yet
		1298	executed).
		1299
		1300	=item IO::AIO::npending
		1301
		1302	Returns the number of requests currently in the pending state (executed,
		1303	but not yet processed by poll_cb).
		1304
		1305	=back
		1306
973	=cut	1307	=cut
974		1308
975	# support function to convert a fd into a perl filehandle
976	sub _fd2fh {
977	return undef if $_[0] < 0;
978
979	# try to generate nice filehandles
980	my $sym = "IO::AIO::fd#$_[0]";
981	local *$sym;
982
983	open *$sym, "+<&=$_[0]" # usually works under any unix
984	or open *$sym, "<&=$_[0]" # cygwin needs this
985	or open *$sym, ">&=$_[0]" # or this
986	or return undef;
987
988	*$sym
989	}
990
991	min_parallel 8;	1309	min_parallel 8;
992		1310
993	END {	1311	END { flush }
994	flush;
995	};
996		1312
997	1;	1313	1;
998		1314
999	=head2 FORK BEHAVIOUR	1315	=head2 FORK BEHAVIOUR
1000		1316
…		…
1020	bytes of memory. In addition, stat requests need a stat buffer (possibly	1336	bytes of memory. In addition, stat requests need a stat buffer (possibly
1021	a few hundred bytes), readdir requires a result buffer and so on. Perl	1337	a few hundred bytes), readdir requires a result buffer and so on. Perl
1022	scalars and other data passed into aio requests will also be locked and	1338	scalars and other data passed into aio requests will also be locked and
1023	will consume memory till the request has entered the done state.	1339	will consume memory till the request has entered the done state.
1024		1340
1025	This is now awfully much, so queuing lots of requests is not usually a	1341	This is not awfully much, so queuing lots of requests is not usually a
1026	problem.	1342	problem.
1027		1343
1028	Per-thread usage:	1344	Per-thread usage:
1029		1345
1030	In the execution phase, some aio requests require more memory for	1346	In the execution phase, some aio requests require more memory for

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Comparing IO-AIO/AIO.pm (file contents): Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC vs. Revision 1.117 by root, Sat Oct 6 14:05:19 2007 UTC

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Comparing IO-AIO/AIO.pm (file contents):
Revision 1.82 by root, Fri Oct 27 20:10:06 2006 UTC vs.
Revision 1.117 by root, Sat Oct 6 14:05:19 2007 UTC