X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=io_uring_engine.cpp;h=03160b12a4abb1f04e83a84acfcf84d7589ad1f1;hb=99a0a43a777176583f3525e11ef62185dd2be740;hp=cadc6c33a79abeb12d2f63387b2f1fa6037b25f2;hpb=48be942bea5a1fabb09e9a0333c6dfb0ac7f2ebc;p=plocate

diff --git a/io_uring_engine.cpp b/io_uring_engine.cpp
index cadc6c3..03160b1 100644
--- a/io_uring_engine.cpp
+++ b/io_uring_engine.cpp
@@ -1,34 +1,44 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
 #include <string.h>
 #ifndef WITHOUT_URING
 #include <liburing.h>
 #endif
+#include "dprintf.h"
 #include "io_uring_engine.h"
 
 #include <functional>
-#include <memory>
-#include <stdint.h>
+#include <iosfwd>
+#include <string>
 #include <unistd.h>
+#include <utility>
 
 using namespace std;
 
-IOUringEngine::IOUringEngine()
+IOUringEngine::IOUringEngine(size_t slop_bytes)
+	: slop_bytes(slop_bytes)
 {
 #ifdef WITHOUT_URING
 	int ret = -1;
+	dprintf("Compiled without liburing support; not using io_uring.\n");
 #else
 	int ret = io_uring_queue_init(queue_depth, &ring, 0);
+	if (ret < 0) {
+		dprintf("io_uring_queue_init() failed; not using io_uring.\n");
+	}
 #endif
 	using_uring = (ret >= 0);
 }
 
-void IOUringEngine::submit_read(int fd, size_t len, off_t offset, function<void(string)> cb)
+void IOUringEngine::submit_read(int fd, size_t len, off_t offset, function<void(string_view)> cb)
 {
 	if (!using_uring) {
 		// Synchronous read.
 		string s;
-		s.resize(len);
+		s.resize(len + slop_bytes);
 		complete_pread(fd, &s[0], len, offset);
-		cb(move(s));
+		cb(string_view(s.data(), len));
 		return;
 	}
 
@@ -47,10 +57,10 @@ void IOUringEngine::submit_read(int fd, size_t len, off_t offset, function<void(
 }
 
 #ifndef WITHOUT_URING
-void IOUringEngine::submit_read_internal(io_uring_sqe *sqe, int fd, size_t len, off_t offset, function<void(string)> cb)
+void IOUringEngine::submit_read_internal(io_uring_sqe *sqe, int fd, size_t len, off_t offset, function<void(string_view)> cb)
 {
 	void *buf;
-	if (posix_memalign(&buf, /*alignment=*/4096, len)) {
+	if (posix_memalign(&buf, /*alignment=*/4096, len + slop_bytes)) {
 		fprintf(stderr, "Couldn't allocate %zu bytes: %s\n", len, strerror(errno));
 		exit(1);
 	}
@@ -71,28 +81,28 @@ void IOUringEngine::finish()
 #ifndef WITHOUT_URING
 	bool anything_to_submit = true;
 	while (pending_reads > 0) {
-		io_uring_cqe *cqes[queue_depth];
-		int num_sqes = io_uring_peek_batch_cqe(&ring, cqes, queue_depth);
-		if (num_sqes == 0) {
+		io_uring_cqe *cqe;
+		if (io_uring_peek_cqe(&ring, &cqe) != 0) {
 			if (anything_to_submit) {
 				// Nothing ready, so submit whatever is pending and then do a blocking wait.
-				int ret = io_uring_submit(&ring);
+				int ret = io_uring_submit_and_wait(&ring, 1);
 				if (ret < 0) {
 					fprintf(stderr, "io_uring_submit(queued): %s\n", strerror(-ret));
 					exit(1);
 				}
 				anything_to_submit = false;
+			} else {
+				int ret = io_uring_wait_cqe(&ring, &cqe);
+				if (ret < 0) {
+					fprintf(stderr, "io_uring_wait_cqe: %s\n", strerror(-ret));
+					exit(1);
+				}
 			}
-			int ret = io_uring_wait_cqe(&ring, &cqes[0]);
-			if (ret < 0) {
-				fprintf(stderr, "io_uring_wait_cqe: %s\n", strerror(-ret));
-				exit(1);
-			}
-			num_sqes = 1;
 		}
 
-		for (int sqe_idx = 0; sqe_idx < num_sqes; ++sqe_idx) {
-			io_uring_cqe *cqe = cqes[sqe_idx];
+		unsigned head;
+		io_uring_for_each_cqe(&ring, head, cqe)
+		{
 			PendingRead *pending = reinterpret_cast<PendingRead *>(cqe->user_data);
 			if (cqe->res <= 0) {
 				fprintf(stderr, "async read failed: %s\n", strerror(-cqe->res));
@@ -119,7 +129,7 @@ void IOUringEngine::finish()
 				--pending_reads;
 
 				size_t old_pending_reads = pending_reads;
-				pending->cb(string(reinterpret_cast<char *>(pending->buf), pending->len));
+				pending->cb(string_view(reinterpret_cast<char *>(pending->buf), pending->len));
 				free(pending->buf);
 				delete pending;
 
@@ -129,19 +139,19 @@ void IOUringEngine::finish()
 					anything_to_submit = true;
 				}
 			}
+		}
 
-			// See if there are any queued reads we can submit now.
-			while (!queued_reads.empty() && pending_reads < queue_depth) {
-				io_uring_sqe *sqe = io_uring_get_sqe(&ring);
-				if (sqe == nullptr) {
-					fprintf(stderr, "io_uring_get_sqe: %s\n", strerror(errno));
-					exit(1);
-				}
-				QueuedRead &qr = queued_reads.front();
-				submit_read_internal(sqe, qr.fd, qr.len, qr.offset, move(qr.cb));
-				queued_reads.pop();
-				anything_to_submit = true;
+		// See if there are any queued reads we can submit now.
+		while (!queued_reads.empty() && pending_reads < queue_depth) {
+			io_uring_sqe *sqe = io_uring_get_sqe(&ring);
+			if (sqe == nullptr) {
+				fprintf(stderr, "io_uring_get_sqe: %s\n", strerror(errno));
+				exit(1);
 			}
+			QueuedRead &qr = queued_reads.front();
+			submit_read_internal(sqe, qr.fd, qr.len, qr.offset, move(qr.cb));
+			queued_reads.pop();
+			anything_to_submit = true;
 		}
 	}
 #endif