MAJOR: polling: rework the whole polling system
This commit heavily changes the polling system in order to definitely
fix the frequent breakage of SSL which needs to remember the last
EAGAIN before deciding whether to poll or not. Now we have a state per
direction for each FD, as opposed to a previous and current state
previously. An FD can have up to 8 different states for each direction,
each of which being the result of a 3-bit combination. These 3 bits
indicate a wish to access the FD, the readiness of the FD and the
subscription of the FD to the polling system.
This means that it will now be possible to remember the state of a
file descriptor across disable/enable sequences that generally happen
during forwarding, where enabling reading on a previously disabled FD
would result in forgetting the EAGAIN flag it met last time.
Several new state manipulation functions have been introduced or
adapted :
- fd_want_{recv,send} : enable receiving/sending on the FD regardless
of its state (sets the ACTIVE flag) ;
- fd_stop_{recv,send} : stop receiving/sending on the FD regardless
of its state (clears the ACTIVE flag) ;
- fd_cant_{recv,send} : report a failure to receive/send on the FD
corresponding to EAGAIN (clears the READY flag) ;
- fd_may_{recv,send} : report the ability to receive/send on the FD
as reported by poll() (sets the READY flag) ;
Some functions are used to report the current FD status :
- fd_{recv,send}_active
- fd_{recv,send}_ready
- fd_{recv,send}_polled
Some functions were removed :
- fd_ev_clr(), fd_ev_set(), fd_ev_rem(), fd_ev_wai()
The POLLHUP/POLLERR flags are now reported as ready so that the I/O layers
knows it can try to access the file descriptor to get this information.
In order to simplify the conditions to add/remove cache entries, a new
function fd_alloc_or_release_cache_entry() was created to be used from
pollers while scanning for updates.
The following pollers have been updated :
ev_select() : done, built, tested on Linux 3.10
ev_poll() : done, built, tested on Linux 3.10
ev_epoll() : done, built, tested on Linux 3.10 & 3.13
ev_kqueue() : done, built, tested on OpenBSD 5.2
diff --git a/include/types/fd.h b/include/types/fd.h
index 3bfe48f..1c2c7c8 100644
--- a/include/types/fd.h
+++ b/include/types/fd.h
@@ -1,8 +1,8 @@
/*
* include/types/fd.h
- * File descriptors states.
+ * File descriptors states - check src/fd.c for explanations.
*
- * Copyright (C) 2000-2009 Willy Tarreau - w@1wt.eu
+ * Copyright (C) 2000-2014 Willy Tarreau - w@1wt.eu
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@@ -45,32 +45,43 @@
#define FD_POLL_DATA (FD_POLL_IN | FD_POLL_OUT)
#define FD_POLL_STICKY (FD_POLL_ERR | FD_POLL_HUP)
-/* Event state for an FD in each direction, as found in the 4 lower bits of
- * fdtab[].state, and in the 4 next bits.
- */
#define FD_EV_ACTIVE 1U
+#define FD_EV_READY 2U
#define FD_EV_POLLED 4U
-#define FD_EV_STATUS (FD_EV_ACTIVE | FD_EV_POLLED)
+
+#define FD_EV_STATUS (FD_EV_ACTIVE | FD_EV_POLLED | FD_EV_READY)
#define FD_EV_STATUS_R (FD_EV_STATUS)
-#define FD_EV_STATUS_W (FD_EV_STATUS << 1)
+#define FD_EV_STATUS_W (FD_EV_STATUS << 4)
#define FD_EV_POLLED_R (FD_EV_POLLED)
-#define FD_EV_POLLED_W (FD_EV_POLLED << 1)
+#define FD_EV_POLLED_W (FD_EV_POLLED << 4)
#define FD_EV_POLLED_RW (FD_EV_POLLED_R | FD_EV_POLLED_W)
#define FD_EV_ACTIVE_R (FD_EV_ACTIVE)
-#define FD_EV_ACTIVE_W (FD_EV_ACTIVE << 1)
+#define FD_EV_ACTIVE_W (FD_EV_ACTIVE << 4)
#define FD_EV_ACTIVE_RW (FD_EV_ACTIVE_R | FD_EV_ACTIVE_W)
-#define FD_EV_CURR_MASK 0x0FU
-#define FD_EV_PREV_MASK 0xF0U
+#define FD_EV_READY_R (FD_EV_READY)
+#define FD_EV_READY_W (FD_EV_READY << 4)
+#define FD_EV_READY_RW (FD_EV_READY_R | FD_EV_READY_W)
+
+enum fd_states {
+ FD_ST_DISABLED = 0,
+ FD_ST_MUSTPOLL,
+ FD_ST_STOPPED,
+ FD_ST_ACTIVE,
+ FD_ST_ABORT,
+ FD_ST_POLLED,
+ FD_ST_PAUSED,
+ FD_ST_READY
+};
/* info about one given fd */
struct fdtab {
int (*iocb)(int fd); /* I/O handler, returns FD_WAIT_* */
void *owner; /* the connection or listener associated with this fd, NULL if closed */
unsigned int cache; /* position+1 in the FD cache. 0=not in cache. */
- unsigned char state; /* FD state for read and write directions (4+4 bits) */
+ unsigned char state; /* FD state for read and write directions (2*3 bits) */
unsigned char ev; /* event seen in return of poll() : FD_POLL_* */
unsigned char new:1; /* 1 if this fd has just been created */
unsigned char updated:1; /* 1 if this fd is already in the update list */