[Dovecot] Patch: ioloop using kqueue/kevent for FreeBSD

Vaclav Haisman V.Haisman at sh.cvut.cz
Wed Dec 14 18:42:45 EET 2005


Only after posting the first patch I realised it is not good enough wrt/ 
IO_ERROR handling. The attached patch should be better.

Vaclav Haisman
-------------- next part --------------
diff -rN -u old-dovecot-cvs/configure.in new-dovecot-cvs/configure.in
--- old-dovecot-cvs/configure.in	2005-12-14 17:33:23.680977636 +0100
+++ new-dovecot-cvs/configure.in	2005-12-14 17:33:29.313807864 +0100
@@ -1,6 +1,10 @@
 AC_INIT(dovecot, 1.0.alpha5, [dovecot at dovecot.org])
 AC_CONFIG_SRCDIR([src])
 
+AC_CANONICAL_BUILD
+AC_CANONICAL_HOST
+AC_CANONICAL_TARGET
+
 AC_CONFIG_HEADERS([config.h])
 AM_INIT_AUTOMAKE
 
@@ -327,6 +331,15 @@
   ])
 fi
 
+if test "$ioloop" = "kqueue"; then
+  AC_CHECK_FUNC(kqueue, [
+    AC_DEFINE(IOLOOP_KQUEUE,, [Implement I/O loop with FreeBSD kqueue()])
+    have_ioloop=yes
+  ], [
+    ioloop=""
+  ])
+fi
+
 if test "$ioloop" = "" || test "$ioloop" = "poll"; then
   AC_CHECK_FUNC(poll, [
     AC_DEFINE(IOLOOP_POLL,, Implement I/O loop with poll())
diff -rN -u old-dovecot-cvs/src/lib/Makefile.am new-dovecot-cvs/src/lib/Makefile.am
--- old-dovecot-cvs/src/lib/Makefile.am	2005-12-14 17:33:23.678298456 +0100
+++ new-dovecot-cvs/src/lib/Makefile.am	2005-12-14 17:33:24.907951306 +0100
@@ -35,6 +35,7 @@
 	ioloop-poll.c \
 	ioloop-select.c \
 	ioloop-epoll.c \
+	ioloop-kqueue.c \
 	lib.c \
 	lib-signals.c \
 	md4.c \
diff -rN -u old-dovecot-cvs/src/lib/ioloop-kqueue.c new-dovecot-cvs/src/lib/ioloop-kqueue.c
--- old-dovecot-cvs/src/lib/ioloop-kqueue.c	1970-01-01 01:00:00.000000000 +0100
+++ new-dovecot-cvs/src/lib/ioloop-kqueue.c	2005-12-14 17:33:26.384132530 +0100
@@ -0,0 +1,210 @@
+/*
+ * FreeBSD kqueue() based ioloop handler.
+ *
+ * Copyright (c) 2005 Vaclav Haisman <v.haisman at sh.cvut.cz>
+ *
+ * This library is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+/* @UNSAFE: whole file */
+
+#include "lib.h"
+#include "ioloop-internal.h"
+
+#ifdef IOLOOP_KQUEUE
+
+#include <sys/types.h>
+#include <sys/event.h>
+#include <sys/time.h>
+
+#ifndef INITIAL_BUF_SIZE
+#  define INITIAL_BUF_SIZE 128
+#endif
+
+
+struct ioloop_handler_context {
+        int kq;
+        size_t evbuf_size;
+        struct kevent *evbuf;
+
+        size_t fds_size;
+        struct fdrecord *fds;
+};
+
+struct fdrecord {
+        struct io *errio;
+        /* IO_READ | IO_WRITE | IO_ERROR */
+        unsigned char mode : 3;
+};
+
+
+void io_loop_handler_init(struct ioloop *ioloop)
+{
+        struct ioloop_handler_context *ctx;
+
+        ioloop->handler_context = ctx =
+                p_new(ioloop->pool, struct ioloop_handler_context, 1);
+        ctx->evbuf_size = INITIAL_BUF_SIZE;
+        ctx->evbuf = p_new(ioloop->pool, struct kevent, ctx->evbuf_size);
+        memset(ctx->evbuf, 0, sizeof(struct kevent) * ctx->evbuf_size);
+        ctx->kq = kqueue ();
+        if (ctx->kq < 0)
+                i_fatal("kqueue(): %m");
+
+        ctx->fds_size = INITIAL_BUF_SIZE;
+        ctx->fds = p_new(ioloop->pool, struct fdrecord, ctx->fds_size);
+        memset(ctx->fds, 0, sizeof(struct fdrecord) * ctx->fds_size);
+}
+
+
+void io_loop_handler_deinit(struct ioloop *ioloop)
+{
+        p_free(ioloop->pool, ioloop->handler_context->evbuf);
+        p_free(ioloop->pool, ioloop->handler_context->fds);
+        p_free(ioloop->pool, ioloop->handler_context);
+}
+
+
+void io_loop_handle_add(struct ioloop *ioloop, struct io *io)
+{
+        struct ioloop_handler_context *ctx = ioloop->handler_context;
+        const int fd = io->fd;
+        struct kevent ev = {fd, 0, EV_ADD | EV_CLEAR | EV_EOF, 0, 0, NULL};
+        enum io_condition condition = io->condition;
+
+        /* grow ctx->fds array if necessary */
+        if ((size_t)fd >= ctx->fds_size)
+        {
+                size_t old_size = ctx->fds_size;
+
+                ctx->fds_size = nearest_power((unsigned int)fd+1);
+                i_assert(ctx->fds_size < (size_t)-1 / sizeof(int));
+
+                ctx->fds = p_realloc(ioloop->pool, ctx->fds,
+                                     sizeof(struct fdrecord) * old_size,
+                                     sizeof(struct fdrecord) * ctx->fds_size);
+                memset(ctx->fds + old_size, 0,
+                       sizeof(struct fdrecord) * (ctx->fds_size - old_size));
+        }
+
+        if (condition & (IO_READ | IO_WRITE))
+                ev.udata = io;
+        if (condition & IO_ERROR)
+                ctx->fds[fd].errio = io;
+
+        if (condition & (IO_READ | IO_ERROR))
+        {
+                ctx->fds[fd].mode |= condition;
+                ev.filter = EVFILT_READ;
+                kevent(ctx->kq, &ev, 1, NULL, 0, NULL);
+        }
+        if (condition & (IO_WRITE | IO_ERROR))
+        {
+                ctx->fds[fd].mode |= condition;
+                ev.filter = EVFILT_WRITE;
+                kevent(ctx->kq, &ev, 1, NULL, 0, NULL);
+        }
+}
+
+
+void io_loop_handle_remove(struct ioloop *ioloop,  struct io *io)
+{
+        struct ioloop_handler_context *ctx = ioloop->handler_context;
+        struct fdrecord * const fds = ctx->fds;
+        const int fd = io->fd;
+        struct kevent ev = {fd, 0, EV_DELETE, 0, 0, NULL};
+        enum io_condition condition = io->condition;
+
+
+        i_assert((size_t)fd < ctx->fds_size);
+        i_assert(fds[fd].mode != 0);
+
+        if (condition & IO_ERROR)
+                fds[fd].errio = NULL;
+        if (condition & (IO_READ | IO_ERROR))
+        {
+                ev.filter = EVFILT_READ;
+                fds[fd].mode &= ~condition;
+                if ((fds[fd].mode & (IO_READ | IO_ERROR)) == 0)
+                        kevent(ctx->kq, &ev, 1, NULL, 0, NULL);
+        }
+        if (condition & (IO_WRITE | IO_ERROR))
+        {
+                ev.filter = EVFILT_WRITE;
+                fds[fd].mode &= ~condition;
+                if ((fds[fd].mode & (IO_WRITE | IO_ERROR)) == 0)
+                        kevent(ctx->kq, &ev, 1, NULL, 0, NULL);
+        }
+}
+
+
+void io_loop_handler_run(struct ioloop *ioloop)
+{
+        struct ioloop_handler_context *ctx = ioloop->handler_context;
+        struct timeval tv;
+        struct timespec ts;
+        unsigned int t_id;
+        int msecs, ret, i;
+
+        /* get the time left for next timeout task */
+        msecs = io_loop_get_wait_time(ioloop->timeouts, &tv, NULL);
+        ts.tv_sec = tv.tv_sec;
+        ts.tv_nsec = tv.tv_usec * 1000;
+
+        /* wait for events */
+        ret = kevent (ctx->kq, NULL, 0, ctx->evbuf, ctx->evbuf_size, &ts);
+        if (ret < 0 && errno != EINTR)
+                i_fatal("kevent(): %m");
+
+        /* execute timeout handlers */
+        io_loop_handle_timeouts(ioloop);
+
+        if (ret <= 0 || !ioloop->running) {
+                /* no I/O events */
+                return;
+        }
+
+        i_assert((size_t)ret <= ctx->evbuf_size);
+
+        /* loop through all received events */
+        for (i = 0; i < ret; ++i)
+        {
+                struct io *io = ctx->evbuf[i].udata;
+
+                i_assert(ctx->evbuf[i].ident < ctx->fds_size);
+                if (ctx->fds[ctx->evbuf[i].ident].mode & IO_ERROR)
+                {
+                        struct io *errio = ctx->fds[ctx->evbuf[i].ident].errio;
+
+                        t_id = t_push();
+                        errio->callback(errio->context);
+                        if (t_pop() != t_id)
+                                i_panic("Leaked a t_pop() call"
+                                        " in I/O handler %p",
+                                        (void *)errio->callback);
+                }
+
+                if (ctx->fds[ctx->evbuf[i].ident].mode & (IO_WRITE | IO_READ))
+                {
+                        t_id = t_push();
+                        io->callback(io->context);
+                        if (t_pop() != t_id)
+                                i_panic("Leaked a t_pop() call"
+                                        " in I/O handler %p",
+                                        (void *)io->callback);
+                }
+        }
+}
+
+
+#endif // IOLOOP_KQUEUE
+
+/*
+Local Variables:
+eval: (c-set-style "linux")
+whitespace-auto-cleanup: t
+End:
+*/



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