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io.cfa @ 95b3a9c

ADTarm-ehast-experimentalenumforall-pointer-decayjacob/cs343-translationnew-ast-unique-exprpthread-emulationqualifiedEnum

Last change on this file since 95b3a9c was 2fab24e3, checked in by Thierry Delisle <tdelisle@…>, 3 years ago
Fixed some warnings and printing.
Property mode set to `100644`
File size: 21.4 KB

Rev	Line
[ecf6b46]	1	//
	2	// Cforall Version 1.0.0 Copyright (C) 2020 University of Waterloo
	3	//
	4	// The contents of this file are covered under the licence agreement in the
	5	// file "LICENCE" distributed with Cforall.
	6	//
	7	// io.cfa --
	8	//
	9	// Author : Thierry Delisle
	10	// Created On : Thu Apr 23 17:31:00 2020
	11	// Last Modified By :
	12	// Last Modified On :
	13	// Update Count :
	14	//
	15
[3e2b9c9]	16	#define __cforall_thread__
	17
[20ab637]	18	#if defined(__CFA_DEBUG__)
	19	// #define __CFA_DEBUG_PRINT_IO__
[e660761]	20	// #define __CFA_DEBUG_PRINT_IO_CORE__
[20ab637]	21	#endif
[4069faad]	22
[f6660520]	23
[3e2b9c9]	24	#if defined(CFA_HAVE_LINUX_IO_URING_H)
[31bb2e1]	25	#define _GNU_SOURCE /* See feature_test_macros(7) */
	26	#include <errno.h>
[3e2b9c9]	27	#include <signal.h>
[31bb2e1]	28	#include <stdint.h>
	29	#include <string.h>
	30	#include <unistd.h>
	31
[92976d9]	32	extern "C" {
	33	#include <sys/syscall.h>
	34
	35	#include <linux/io_uring.h>
	36	}
	37
[3e2b9c9]	38	#include "stats.hfa"
	39	#include "kernel.hfa"
	40	#include "kernel/fwd.hfa"
	41	#include "io/types.hfa"
[185efe6]	42
[2fab24e3]	43	__attribute__((unused)) static const char * opcodes[] = {
[426f60c]	44	"OP_NOP",
	45	"OP_READV",
	46	"OP_WRITEV",
	47	"OP_FSYNC",
	48	"OP_READ_FIXED",
	49	"OP_WRITE_FIXED",
	50	"OP_POLL_ADD",
	51	"OP_POLL_REMOVE",
	52	"OP_SYNC_FILE_RANGE",
	53	"OP_SENDMSG",
	54	"OP_RECVMSG",
	55	"OP_TIMEOUT",
	56	"OP_TIMEOUT_REMOVE",
	57	"OP_ACCEPT",
	58	"OP_ASYNC_CANCEL",
	59	"OP_LINK_TIMEOUT",
	60	"OP_CONNECT",
	61	"OP_FALLOCATE",
	62	"OP_OPENAT",
	63	"OP_CLOSE",
	64	"OP_FILES_UPDATE",
	65	"OP_STATX",
	66	"OP_READ",
	67	"OP_WRITE",
	68	"OP_FADVISE",
	69	"OP_MADVISE",
	70	"OP_SEND",
	71	"OP_RECV",
	72	"OP_OPENAT2",
	73	"OP_EPOLL_CTL",
	74	"OP_SPLICE",
	75	"OP_PROVIDE_BUFFERS",
	76	"OP_REMOVE_BUFFERS",
	77	"OP_TEE",
	78	"INVALID_OP"
	79	};
	80
[2fafe7e]	81	// returns true of acquired as leader or second leader
	82	static inline bool try_lock( __leaderlock_t & this ) {
	83	const uintptr_t thrd = 1z \| (uintptr_t)active_thread();
	84	bool block;
	85	disable_interrupts();
	86	for() {
	87	struct $thread * expected = this.value;
	88	if( 1p != expected && 0p != expected ) {
	89	/* paranoid */ verify( thrd != (uintptr_t)expected ); // We better not already be the next leader
	90	enable_interrupts( __cfaabi_dbg_ctx );
	91	return false;
	92	}
	93	struct $thread * desired;
	94	if( 0p == expected ) {
	95	// If the lock isn't locked acquire it, no need to block
	96	desired = 1p;
	97	block = false;
	98	}
	99	else {
	100	// If the lock is already locked try becomming the next leader
	101	desired = (struct $thread *)thrd;
	102	block = true;
	103	}
	104	if( __atomic_compare_exchange_n(&this.value, &expected, desired, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ) break;
	105	}
	106	if( block ) {
	107	enable_interrupts( __cfaabi_dbg_ctx );
[e235429]	108	park();
[2fafe7e]	109	disable_interrupts();
	110	}
	111	return true;
	112	}
	113
	114	static inline bool next( __leaderlock_t & this ) {
[8fc652e0]	115	/* paranoid */ verify( ! __preemption_enabled() );
[2fafe7e]	116	struct $thread * nextt;
	117	for() {
	118	struct $thread * expected = this.value;
	119	/* paranoid */ verify( (1 & (uintptr_t)expected) == 1 ); // The lock better be locked
	120
	121	struct $thread * desired;
	122	if( 1p == expected ) {
	123	// No next leader, just unlock
	124	desired = 0p;
	125	nextt = 0p;
	126	}
	127	else {
	128	// There is a next leader, remove but keep locked
	129	desired = 1p;
	130	nextt = (struct $thread *)(~1z & (uintptr_t)expected);
	131	}
	132	if( __atomic_compare_exchange_n(&this.value, &expected, desired, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST) ) break;
	133	}
	134
	135	if(nextt) {
[b4b63e8]	136	unpark( nextt );
[2fafe7e]	137	enable_interrupts( __cfaabi_dbg_ctx );
	138	return true;
	139	}
	140	enable_interrupts( __cfaabi_dbg_ctx );
	141	return false;
	142	}
	143
[92976d9]	144	//=============================================================================================
[3e2b9c9]	145	// I/O Syscall
[92976d9]	146	//=============================================================================================
[3e2b9c9]	147	static int __io_uring_enter( struct __io_data & ring, unsigned to_submit, bool get ) {
[20ab637]	148	bool need_sys_to_submit = false;
	149	bool need_sys_to_complete = false;
	150	unsigned flags = 0;
	151
	152	TO_SUBMIT:
	153	if( to_submit > 0 ) {
	154	if( !(ring.ring_flags & IORING_SETUP_SQPOLL) ) {
	155	need_sys_to_submit = true;
	156	break TO_SUBMIT;
	157	}
	158	if( (*ring.submit_q.flags) & IORING_SQ_NEED_WAKEUP ) {
	159	need_sys_to_submit = true;
	160	flags \|= IORING_ENTER_SQ_WAKEUP;
	161	}
	162	}
	163
	164	if( get && !(ring.ring_flags & IORING_SETUP_SQPOLL) ) {
	165	flags \|= IORING_ENTER_GETEVENTS;
	166	if( (ring.ring_flags & IORING_SETUP_IOPOLL) ) {
	167	need_sys_to_complete = true;
	168	}
	169	}
	170
	171	int ret = 0;
	172	if( need_sys_to_submit \|\| need_sys_to_complete ) {
[ece0e80]	173	__cfadbg_print_safe(io_core, "Kernel I/O : IO_URING enter %d %u %u\n", ring.fd, to_submit, flags);
[b982fb2]	174	ret = syscall( __NR_io_uring_enter, ring.fd, to_submit, 0, flags, (sigset_t *)0p, _NSIG / 8);
[2fab24e3]	175	__cfadbg_print_safe(io_core, "Kernel I/O : IO_URING %d returned %d\n", ring.fd, ret);
	176
[20ab637]	177	if( ret < 0 ) {
	178	switch((int)errno) {
	179	case EAGAIN:
	180	case EINTR:
[2fab24e3]	181	case EBUSY:
[20ab637]	182	ret = -1;
	183	break;
	184	default:
	185	abort( "KERNEL ERROR: IO_URING SYSCALL - (%d) %s\n", (int)errno, strerror(errno) );
	186	}
	187	}
	188	}
	189
	190	// Memory barrier
	191	__atomic_thread_fence( __ATOMIC_SEQ_CST );
	192	return ret;
	193	}
	194
[92976d9]	195	//=============================================================================================
	196	// I/O Polling
	197	//=============================================================================================
[1d5e4711]	198	static unsigned __collect_submitions( struct __io_data & ring );
[4998155]	199	static __u32 __release_consumed_submission( struct __io_data & ring );
[35285fd]	200	static inline void __clean( volatile struct io_uring_sqe * sqe );
[1d5e4711]	201
[426f60c]	202	// Process a single completion message from the io_uring
	203	// This is NOT thread-safe
	204	static inline void process( volatile struct io_uring_cqe & cqe ) {
[c402739f]	205	struct io_future_t * future = (struct io_future_t *)(uintptr_t)cqe.user_data;
[fe9468e2]	206	__cfadbg_print_safe( io, "Kernel I/O : Syscall completed : cqe %p, result %d for %p\n", &cqe, cqe.res, future );
[5751a56]	207
[c402739f]	208	fulfil( *future, cqe.res );
[5751a56]	209	}
	210
[f00b26d4]	211	static [int, bool] __drain_io( & struct __io_data ring ) {
[8fc652e0]	212	/* paranoid */ verify( ! __preemption_enabled() );
[e46c753]	213
[5dadc9b]	214	unsigned to_submit = 0;
[f00b26d4]	215	if( ring.poller_submits ) {
[5dadc9b]	216	// If the poller thread also submits, then we need to aggregate the submissions which are ready
[e46c753]	217	to_submit = __collect_submitions( ring );
[5dadc9b]	218	}
	219
[f00b26d4]	220	int ret = __io_uring_enter(ring, to_submit, true);
[20ab637]	221	if( ret < 0 ) {
	222	return [0, true];
	223	}
[1d5e4711]	224
[20ab637]	225	// update statistics
	226	if (to_submit > 0) {
[1d5e4711]	227	__STATS__( true,
	228	if( to_submit > 0 ) {
	229	io.submit_q.submit_avg.rdy += to_submit;
	230	io.submit_q.submit_avg.csm += ret;
	231	io.submit_q.submit_avg.cnt += 1;
	232	}
	233	)
[6f121b8]	234	}
	235
[426f60c]	236	__atomic_thread_fence( __ATOMIC_SEQ_CST );
	237
[20ab637]	238	// Release the consumed SQEs
	239	__release_consumed_submission( ring );
[6f121b8]	240
[d384787]	241	// Drain the queue
[92976d9]	242	unsigned head = *ring.completion_q.head;
[6f121b8]	243	unsigned tail = *ring.completion_q.tail;
[4998155]	244	const __u32 mask = *ring.completion_q.mask;
[6f121b8]	245
[d384787]	246	// Nothing was new return 0
	247	if (head == tail) {
[e46c753]	248	return [0, to_submit > 0];
[d384787]	249	}
[92976d9]	250
[4998155]	251	__u32 count = tail - head;
[1d5e4711]	252	/* paranoid */ verify( count != 0 );
[d384787]	253	for(i; count) {
[6f121b8]	254	unsigned idx = (head + i) & mask;
[426f60c]	255	volatile struct io_uring_cqe & cqe = ring.completion_q.cqes[idx];
[92976d9]	256
[d384787]	257	/* paranoid */ verify(&cqe);
[92976d9]	258
[f00b26d4]	259	process( cqe );
[d384787]	260	}
[2d8f7b0]	261
[92976d9]	262	// Mark to the kernel that the cqe has been seen
	263	// Ensure that the kernel only sees the new value of the head index after the CQEs have been read.
[426f60c]	264	__atomic_fetch_add( ring.completion_q.head, count, __ATOMIC_SEQ_CST );
[92976d9]	265
[5dadc9b]	266	return [count, count > 0 \|\| to_submit > 0];
[92976d9]	267	}
	268
[f00b26d4]	269	void main( $io_ctx_thread & this ) {
[d48b174]	270	__ioctx_register( this );
[1539bbd]	271
[426f60c]	272	__cfadbg_print_safe(io_core, "Kernel I/O : IO poller %d (%p) ready\n", this.ring->fd, &this);
[1539bbd]	273
[ece0e80]	274	const int reset_cnt = 5;
	275	int reset = reset_cnt;
[61dd73d]	276	// Then loop until we need to start
[ece0e80]	277	LOOP:
[f00b26d4]	278	while(!__atomic_load_n(&this.done, __ATOMIC_SEQ_CST)) {
[61dd73d]	279	// Drain the io
[5dadc9b]	280	int count;
	281	bool again;
[13c5e19]	282	disable_interrupts();
[f00b26d4]	283	[count, again] = __drain_io( *this.ring );
[5dadc9b]	284
[ece0e80]	285	if(!again) reset--;
[3c039b0]	286
[13c5e19]	287	// Update statistics
[47746a2]	288	__STATS__( true,
	289	io.complete_q.completed_avg.val += count;
[dcb5f8d]	290	io.complete_q.completed_avg.cnt += 1;
[47746a2]	291	)
[13c5e19]	292	enable_interrupts( __cfaabi_dbg_ctx );
[3c039b0]	293
[5dadc9b]	294	// If we got something, just yield and check again
[ece0e80]	295	if(reset > 1) {
[61dd73d]	296	yield();
[ece0e80]	297	continue LOOP;
[61dd73d]	298	}
[ece0e80]	299
[426f60c]	300	// We alread failed to find completed entries a few time.
[ece0e80]	301	if(reset == 1) {
	302	// Rearm the context so it can block
	303	// but don't block right away
	304	// we need to retry one last time in case
	305	// something completed just now
[d48b174]	306	__ioctx_prepare_block( this );
[ece0e80]	307	continue LOOP;
	308	}
	309
[93526ef]	310	__STATS__( false,
[dcb5f8d]	311	io.complete_q.blocks += 1;
	312	)
[426f60c]	313	__cfadbg_print_safe(io_core, "Kernel I/O : Parking io poller %d (%p)\n", this.ring->fd, &this);
[5dadc9b]	314
[3e2b9c9]	315	// block this thread
[f00b26d4]	316	wait( this.sem );
[ece0e80]	317
	318	// restore counter
	319	reset = reset_cnt;
[f6660520]	320	}
[61dd73d]	321
[426f60c]	322	__cfadbg_print_safe(io_core, "Kernel I/O : Fast poller %d (%p) stopping\n", this.ring->fd, &this);
[d611995]	323
	324	__ioctx_unregister( this );
[61dd73d]	325	}
[f6660520]	326
[92976d9]	327	//=============================================================================================
	328	// I/O Submissions
	329	//=============================================================================================
	330
[2d8f7b0]	331	// Submition steps :
[e46c753]	332	// 1 - Allocate a queue entry. The ring already has memory for all entries but only the ones
[2d8f7b0]	333	// listed in sq.array are visible by the kernel. For those not listed, the kernel does not
	334	// offer any assurance that an entry is not being filled by multiple flags. Therefore, we
	335	// need to write an allocator that allows allocating concurrently.
	336	//
[e46c753]	337	// 2 - Actually fill the submit entry, this is the only simple and straightforward step.
[2d8f7b0]	338	//
[e46c753]	339	// 3 - Append the entry index to the array and adjust the tail accordingly. This operation
[2d8f7b0]	340	// needs to arrive to two concensus at the same time:
	341	// A - The order in which entries are listed in the array: no two threads must pick the
	342	// same index for their entries
	343	// B - When can the tail be update for the kernel. EVERY entries in the array between
	344	// head and tail must be fully filled and shouldn't ever be touched again.
	345	//
	346
[426f60c]	347	// Allocate an submit queue entry.
	348	// The kernel cannot see these entries until they are submitted, but other threads must be
	349	// able to see which entries can be used and which are already un used by an other thread
	350	// for convenience, return both the index and the pointer to the sqe
	351	// sqe == &sqes[idx]
	352	[* volatile struct io_uring_sqe, __u32] __submit_alloc( struct __io_data & ring, __u64 data ) {
[e46c753]	353	/* paranoid */ verify( data != 0 );
[13c5e19]	354
[6f121b8]	355	// Prepare the data we need
	356	__attribute((unused)) int len = 0;
	357	__attribute((unused)) int block = 0;
[4998155]	358	__u32 cnt = *ring.submit_q.num;
	359	__u32 mask = *ring.submit_q.mask;
[8ae4165]	360
[fe9468e2]	361	__u32 off = thread_rand();
[6f121b8]	362
	363	// Loop around looking for an available spot
[13c5e19]	364	for() {
[6f121b8]	365	// Look through the list starting at some offset
	366	for(i; cnt) {
[426f60c]	367	__u64 expected = 3;
	368	__u32 idx = (i + off) & mask; // Get an index from a random
	369	volatile struct io_uring_sqe * sqe = &ring.submit_q.sqes[idx];
[4998155]	370	volatile __u64 * udata = &sqe->user_data;
[6f121b8]	371
[426f60c]	372	// Allocate the entry by CASing the user_data field from 0 to the future address
[6f121b8]	373	if( *udata == expected &&
	374	__atomic_compare_exchange_n( udata, &expected, data, true, __ATOMIC_SEQ_CST, __ATOMIC_RELAXED ) )
	375	{
	376	// update statistics
[47746a2]	377	__STATS__( false,
	378	io.submit_q.alloc_avg.val += len;
	379	io.submit_q.alloc_avg.block += block;
	380	io.submit_q.alloc_avg.cnt += 1;
	381	)
[6f121b8]	382
[426f60c]	383	// debug log
[ece0e80]	384	__cfadbg_print_safe( io, "Kernel I/O : allocated [%p, %u] for %p (%p)\n", sqe, idx, active_thread(), (void*)data );
[13c5e19]	385
[6f121b8]	386	// Success return the data
	387	return [sqe, idx];
	388	}
	389	verify(expected != data);
[2489d31]	390
[426f60c]	391	// This one was used
[6f121b8]	392	len ++;
	393	}
[2489d31]	394
[6f121b8]	395	block++;
[426f60c]	396
[6f121b8]	397	yield();
	398	}
[2489d31]	399	}
	400
[4998155]	401	static inline __u32 __submit_to_ready_array( struct __io_data & ring, __u32 idx, const __u32 mask ) {
[df40a56]	402	/* paranoid */ verify( idx <= mask );
	403	/* paranoid */ verify( idx != -1ul32 );
	404
	405	// We need to find a spot in the ready array
	406	__attribute((unused)) int len = 0;
	407	__attribute((unused)) int block = 0;
[4998155]	408	__u32 ready_mask = ring.submit_q.ready_cnt - 1;
[df40a56]	409
[fe9468e2]	410	__u32 off = thread_rand();
[df40a56]	411
[4998155]	412	__u32 picked;
[df40a56]	413	LOOKING: for() {
	414	for(i; ring.submit_q.ready_cnt) {
	415	picked = (i + off) & ready_mask;
[4998155]	416	__u32 expected = -1ul32;
[df40a56]	417	if( __atomic_compare_exchange_n( &ring.submit_q.ready[picked], &expected, idx, true, __ATOMIC_SEQ_CST, __ATOMIC_RELAXED ) ) {
	418	break LOOKING;
	419	}
	420	verify(expected != idx);
	421
	422	len ++;
	423	}
	424
	425	block++;
[2fafe7e]	426
	427	__u32 released = __release_consumed_submission( ring );
	428	if( released == 0 ) {
[34b61882]	429	yield();
	430	}
[df40a56]	431	}
	432
	433	// update statistics
[47746a2]	434	__STATS__( false,
	435	io.submit_q.look_avg.val += len;
	436	io.submit_q.look_avg.block += block;
	437	io.submit_q.look_avg.cnt += 1;
	438	)
[df40a56]	439
	440	return picked;
	441	}
	442
[4998155]	443	void __submit( struct io_context * ctx, __u32 idx ) __attribute__((nonnull (1))) {
[f00b26d4]	444	__io_data & ring = *ctx->thrd.ring;
[426f60c]	445
	446	{
	447	__attribute__((unused)) volatile struct io_uring_sqe * sqe = &ring.submit_q.sqes[idx];
	448	__cfadbg_print_safe( io,
	449	"Kernel I/O : submitting %u (%p) for %p\n"
	450	" data: %p\n"
	451	" opcode: %s\n"
	452	" fd: %d\n"
	453	" flags: %d\n"
	454	" prio: %d\n"
	455	" off: %p\n"
	456	" addr: %p\n"
	457	" len: %d\n"
	458	" other flags: %d\n"
	459	" splice fd: %d\n"
	460	" pad[0]: %llu\n"
	461	" pad[1]: %llu\n"
	462	" pad[2]: %llu\n",
	463	idx, sqe,
	464	active_thread(),
	465	(void*)sqe->user_data,
	466	opcodes[sqe->opcode],
	467	sqe->fd,
	468	sqe->flags,
	469	sqe->ioprio,
[2fab24e3]	470	(void*)sqe->off,
	471	(void*)sqe->addr,
[426f60c]	472	sqe->len,
	473	sqe->accept_flags,
	474	sqe->splice_fd_in,
	475	sqe->__pad2[0],
	476	sqe->__pad2[1],
	477	sqe->__pad2[2]
	478	);
	479	}
	480
	481
[5dadc9b]	482	// Get now the data we definetely need
[4998155]	483	volatile __u32 * const tail = ring.submit_q.tail;
	484	const __u32 mask = *ring.submit_q.mask;
[2489d31]	485
[5dadc9b]	486	// There are 2 submission schemes, check which one we are using
[f00b26d4]	487	if( ring.poller_submits ) {
[5dadc9b]	488	// If the poller thread submits, then we just need to add this to the ready array
[df40a56]	489	__submit_to_ready_array( ring, idx, mask );
[5dadc9b]	490
[f00b26d4]	491	post( ctx->thrd.sem );
[5dadc9b]	492
[dd4e2d7]	493	__cfadbg_print_safe( io, "Kernel I/O : Added %u to ready for %p\n", idx, active_thread() );
[2d8f7b0]	494	}
[f00b26d4]	495	else if( ring.eager_submits ) {
[2fab24e3]	496	__attribute__((unused)) __u32 picked = __submit_to_ready_array( ring, idx, mask );
[e46c753]	497
[2fafe7e]	498	#if defined(LEADER_LOCK)
	499	if( !try_lock(ring.submit_q.submit_lock) ) {
[47746a2]	500	__STATS__( false,
	501	io.submit_q.helped += 1;
	502	)
[e46c753]	503	return;
	504	}
[8fc652e0]	505	/* paranoid */ verify( ! __preemption_enabled() );
[2fafe7e]	506	__STATS__( true,
	507	io.submit_q.leader += 1;
	508	)
	509	#else
	510	for() {
	511	yield();
	512
	513	if( try_lock(ring.submit_q.submit_lock __cfaabi_dbg_ctx2) ) {
	514	__STATS__( false,
	515	io.submit_q.leader += 1;
	516	)
	517	break;
	518	}
	519
	520	// If some one else collected our index, we are done
	521	#warning ABA problem
	522	if( ring.submit_q.ready[picked] != idx ) {
	523	__STATS__( false,
	524	io.submit_q.helped += 1;
	525	)
	526	return;
	527	}
[e46c753]	528
[47746a2]	529	__STATS__( false,
[2fafe7e]	530	io.submit_q.busy += 1;
[47746a2]	531	)
[e46c753]	532	}
[2fafe7e]	533	#endif
[e46c753]	534
	535	// We got the lock
[be36ec3]	536	// Collect the submissions
[e46c753]	537	unsigned to_submit = __collect_submitions( ring );
	538
[be36ec3]	539	// Actually submit
	540	int ret = __io_uring_enter( ring, to_submit, false );
[309d814]	541
[2fafe7e]	542	#if defined(LEADER_LOCK)
[8fc652e0]	543	/* paranoid */ verify( ! __preemption_enabled() );
[2fafe7e]	544	next(ring.submit_q.submit_lock);
	545	#else
	546	unlock(ring.submit_q.submit_lock);
	547	#endif
[ece0e80]	548	if( ret < 0 ) {
	549	return;
	550	}
[e46c753]	551
	552	// Release the consumed SQEs
[34b61882]	553	__release_consumed_submission( ring );
[e46c753]	554
	555	// update statistics
[be36ec3]	556	__STATS__( false,
[47746a2]	557	io.submit_q.submit_avg.rdy += to_submit;
	558	io.submit_q.submit_avg.csm += ret;
	559	io.submit_q.submit_avg.cnt += 1;
	560	)
[ece0e80]	561
	562	__cfadbg_print_safe( io, "Kernel I/O : submitted %u (among %u) for %p\n", idx, ret, active_thread() );
[e46c753]	563	}
[426f60c]	564	else
	565	{
[5dadc9b]	566	// get mutual exclusion
[2fafe7e]	567	#if defined(LEADER_LOCK)
	568	while(!try_lock(ring.submit_q.submit_lock));
	569	#else
	570	lock(ring.submit_q.submit_lock __cfaabi_dbg_ctx2);
	571	#endif
[2489d31]	572
[426f60c]	573	/* paranoid */ verifyf( ring.submit_q.sqes[ idx ].user_data != 3ul64,
[20ab637]	574	/* paranoid */ "index %u already reclaimed\n"
	575	/* paranoid */ "head %u, prev %u, tail %u\n"
	576	/* paranoid */ "[-0: %u,-1: %u,-2: %u,-3: %u]\n",
	577	/* paranoid */ idx,
	578	/* paranoid / ring.submit_q.head, ring.submit_q.prev_head, *tail
	579	/* paranoid / ,ring.submit_q.array[ ((ring.submit_q.head) - 0) & (*ring.submit_q.mask) ]
	580	/* paranoid / ,ring.submit_q.array[ ((ring.submit_q.head) - 1) & (*ring.submit_q.mask) ]
	581	/* paranoid / ,ring.submit_q.array[ ((ring.submit_q.head) - 2) & (*ring.submit_q.mask) ]
	582	/* paranoid / ,ring.submit_q.array[ ((ring.submit_q.head) - 3) & (*ring.submit_q.mask) ]
	583	/* paranoid */ );
	584
[5dadc9b]	585	// Append to the list of ready entries
	586
	587	/* paranoid */ verify( idx <= mask );
[20ab637]	588	ring.submit_q.array[ (*tail) & mask ] = idx;
[5dadc9b]	589	__atomic_fetch_add(tail, 1ul32, __ATOMIC_SEQ_CST);
[d384787]	590
[5dadc9b]	591	// Submit however, many entries need to be submitted
[f00b26d4]	592	int ret = __io_uring_enter( ring, 1, false );
[5dadc9b]	593	if( ret < 0 ) {
	594	switch((int)errno) {
	595	default:
	596	abort( "KERNEL ERROR: IO_URING SUBMIT - %s\n", strerror(errno) );
	597	}
	598	}
[d384787]	599
[426f60c]	600	/* paranoid */ verify(ret == 1);
	601
[5dadc9b]	602	// update statistics
[47746a2]	603	__STATS__( false,
	604	io.submit_q.submit_avg.csm += 1;
	605	io.submit_q.submit_avg.cnt += 1;
	606	)
[5dadc9b]	607
[426f60c]	608	{
	609	__attribute__((unused)) volatile __u32 * const head = ring.submit_q.head;
	610	__attribute__((unused)) __u32 last_idx = ring.submit_q.array[ ((*head) - 1) & mask ];
	611	__attribute__((unused)) volatile struct io_uring_sqe * sqe = &ring.submit_q.sqes[last_idx];
	612
	613	__cfadbg_print_safe( io,
	614	"Kernel I/O : last submitted is %u (%p)\n"
	615	" data: %p\n"
	616	" opcode: %s\n"
	617	" fd: %d\n"
	618	" flags: %d\n"
	619	" prio: %d\n"
	620	" off: %p\n"
	621	" addr: %p\n"
	622	" len: %d\n"
	623	" other flags: %d\n"
	624	" splice fd: %d\n"
	625	" pad[0]: %llu\n"
	626	" pad[1]: %llu\n"
	627	" pad[2]: %llu\n",
	628	last_idx, sqe,
	629	(void*)sqe->user_data,
	630	opcodes[sqe->opcode],
	631	sqe->fd,
	632	sqe->flags,
	633	sqe->ioprio,
[2fab24e3]	634	(void*)sqe->off,
	635	(void*)sqe->addr,
[426f60c]	636	sqe->len,
	637	sqe->accept_flags,
	638	sqe->splice_fd_in,
	639	sqe->__pad2[0],
	640	sqe->__pad2[1],
	641	sqe->__pad2[2]
	642	);
	643	}
	644
	645	__atomic_thread_fence( __ATOMIC_SEQ_CST );
[34b61882]	646	// Release the consumed SQEs
[2fab24e3]	647
[34b61882]	648	__release_consumed_submission( ring );
[426f60c]	649	// ring.submit_q.sqes[idx].user_data = 3ul64;
[7bfc849]	650
[2fafe7e]	651	#if defined(LEADER_LOCK)
	652	next(ring.submit_q.submit_lock);
	653	#else
	654	unlock(ring.submit_q.submit_lock);
	655	#endif
[dd4e2d7]	656
[426f60c]	657	__cfadbg_print_safe( io, "Kernel I/O : submitted %u for %p\n", idx, active_thread() );
[5dadc9b]	658	}
[2489d31]	659	}
[e46c753]	660
[d2b5d2d]	661	// #define PARTIAL_SUBMIT 32
[426f60c]	662
	663	// go through the list of submissions in the ready array and moved them into
	664	// the ring's submit queue
[e46c753]	665	static unsigned __collect_submitions( struct __io_data & ring ) {
	666	/* paranoid */ verify( ring.submit_q.ready != 0p );
	667	/* paranoid */ verify( ring.submit_q.ready_cnt > 0 );
	668
	669	unsigned to_submit = 0;
[4998155]	670	__u32 tail = *ring.submit_q.tail;
	671	const __u32 mask = *ring.submit_q.mask;
[1095ccd]	672	#if defined(PARTIAL_SUBMIT)
	673	#if defined(LEADER_LOCK)
	674	#error PARTIAL_SUBMIT and LEADER_LOCK cannot co-exist
	675	#endif
	676	const __u32 cnt = ring.submit_q.ready_cnt > PARTIAL_SUBMIT ? PARTIAL_SUBMIT : ring.submit_q.ready_cnt;
	677	const __u32 offset = ring.submit_q.prev_ready;
	678	ring.submit_q.prev_ready += cnt;
	679	#else
	680	const __u32 cnt = ring.submit_q.ready_cnt;
	681	const __u32 offset = 0;
	682	#endif
[e46c753]	683
	684	// Go through the list of ready submissions
[1095ccd]	685	for( c; cnt ) {
	686	__u32 i = (offset + c) % ring.submit_q.ready_cnt;
	687
[e46c753]	688	// replace any submission with the sentinel, to consume it.
[4998155]	689	__u32 idx = __atomic_exchange_n( &ring.submit_q.ready[i], -1ul32, __ATOMIC_RELAXED);
[e46c753]	690
	691	// If it was already the sentinel, then we are done
	692	if( idx == -1ul32 ) continue;
	693
	694	// If we got a real submission, append it to the list
	695	ring.submit_q.array[ (tail + to_submit) & mask ] = idx & mask;
	696	to_submit++;
	697	}
	698
	699	// Increment the tail based on how many we are ready to submit
	700	__atomic_fetch_add(ring.submit_q.tail, to_submit, __ATOMIC_SEQ_CST);
	701
	702	return to_submit;
	703	}
[34b61882]	704
[426f60c]	705	// Go through the ring's submit queue and release everything that has already been consumed
	706	// by io_uring
[4998155]	707	static __u32 __release_consumed_submission( struct __io_data & ring ) {
	708	const __u32 smask = *ring.submit_q.mask;
[732b406]	709
[426f60c]	710	// We need to get the lock to copy the old head and new head
[732b406]	711	if( !try_lock(ring.submit_q.release_lock __cfaabi_dbg_ctx2) ) return 0;
[426f60c]	712	__attribute__((unused))
	713	__u32 ctail = *ring.submit_q.tail; // get the current tail of the queue
	714	__u32 chead = *ring.submit_q.head; // get the current head of the queue
	715	__u32 phead = ring.submit_q.prev_head; // get the head the last time we were here
	716	ring.submit_q.prev_head = chead; // note up to were we processed
[732b406]	717	unlock(ring.submit_q.release_lock);
	718
[426f60c]	719	// the 3 fields are organized like this diagram
	720	// except it's are ring
	721	// ---+--------+--------+----
	722	// ---+--------+--------+----
	723	// ^ ^ ^
	724	// phead chead ctail
	725
	726	// make sure ctail doesn't wrap around and reach phead
	727	/* paranoid */ verify(
	728	(ctail >= chead && chead >= phead)
	729	\|\| (chead >= phead && phead >= ctail)
	730	\|\| (phead >= ctail && ctail >= chead)
	731	);
	732
	733	// find the range we need to clear
[4998155]	734	__u32 count = chead - phead;
[426f60c]	735
	736	// We acquired an previous-head/current-head range
	737	// go through the range and release the sqes
[34b61882]	738	for( i; count ) {
[4998155]	739	__u32 idx = ring.submit_q.array[ (phead + i) & smask ];
[426f60c]	740
	741	/* paranoid */ verify( 0 != ring.submit_q.sqes[ idx ].user_data );
[35285fd]	742	__clean( &ring.submit_q.sqes[ idx ] );
[34b61882]	743	}
	744	return count;
	745	}
[35285fd]	746
	747	void __sqe_clean( volatile struct io_uring_sqe * sqe ) {
	748	__clean( sqe );
	749	}
	750
	751	static inline void __clean( volatile struct io_uring_sqe * sqe ) {
	752	// If we are in debug mode, thrash the fields to make sure we catch reclamation errors
	753	__cfaabi_dbg_debug_do(
	754	memset(sqe, 0xde, sizeof(*sqe));
[ec19b21]	755	sqe->opcode = (sizeof(opcodes) / sizeof(const char *)) - 1;
[35285fd]	756	);
	757
	758	// Mark the entry as unused
	759	__atomic_store_n(&sqe->user_data, 3ul64, __ATOMIC_SEQ_CST);
	760	}
[47746a2]	761	#endif

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