[PATCH xserver 03/20] os: Implement support for NotifyFd X_NOTIFY_WRITE
Keith Packard
keithp at keithp.com
Wed Nov 11 22:02:03 PST 2015
This adds the ability to be notified when a file descriptor is
available for writing.
Signed-off-by: Keith Packard <keithp at keithp.com>
---
os/WaitFor.c | 30 ++++++++++++++++++++----------
os/connection.c | 40 +++++++++++++++++++++++++++++++---------
os/io.c | 8 ++++----
os/osdep.h | 5 ++++-
4 files changed, 59 insertions(+), 24 deletions(-)
diff --git a/os/WaitFor.c b/os/WaitFor.c
index 12b21bb..b579e1b 100644
--- a/os/WaitFor.c
+++ b/os/WaitFor.c
@@ -156,6 +156,7 @@ WaitForSomething(int *pClientsReady)
fd_set devicesReadable;
CARD32 now = 0;
Bool someReady = FALSE;
+ Bool someNotifyWriteReady = FALSE;
FD_ZERO(&clientsReadable);
FD_ZERO(&clientsWritable);
@@ -213,9 +214,10 @@ WaitForSomething(int *pClientsReady)
/* keep this check close to select() call to minimize race */
if (dispatchException)
i = -1;
- else if (AnyClientsWriteBlocked) {
- XFD_COPYSET(&ClientsWriteBlocked, &clientsWritable);
- i = Select(MaxClients, &LastSelectMask, &clientsWritable, NULL, wt);
+ else if (AnyWritesPending) {
+ XFD_COPYSET(&ClientsWriteBlocked, &LastSelectWriteMask);
+ XFD_ORSET(&LastSelectWriteMask, &NotifyWriteFds, &LastSelectWriteMask);
+ i = Select(MaxClients, &LastSelectMask, &LastSelectWriteMask, NULL, wt);
}
else {
i = Select(MaxClients, &LastSelectMask, NULL, NULL, wt);
@@ -291,12 +293,20 @@ WaitForSomething(int *pClientsReady)
}
if (someReady)
XFD_ORSET(&LastSelectMask, &ClientsWithInput, &LastSelectMask);
- if (AnyClientsWriteBlocked && XFD_ANYSET(&clientsWritable)) {
- NewOutputPending = TRUE;
- XFD_ORSET(&OutputPending, &clientsWritable, &OutputPending);
- XFD_UNSET(&ClientsWriteBlocked, &clientsWritable);
- if (!XFD_ANYSET(&ClientsWriteBlocked))
- AnyClientsWriteBlocked = FALSE;
+ if (AnyWritesPending) {
+ XFD_ANDSET(&clientsWritable, &LastSelectWriteMask, &ClientsWriteBlocked);
+ if (XFD_ANYSET(&clientsWritable)) {
+ NewOutputPending = TRUE;
+ XFD_ORSET(&OutputPending, &clientsWritable, &OutputPending);
+ XFD_UNSET(&ClientsWriteBlocked, &clientsWritable);
+ if (!XFD_ANYSET(&ClientsWriteBlocked) && NumNotifyWriteFd == 0)
+ AnyWritesPending = FALSE;
+ }
+ if (NumNotifyWriteFd != 0) {
+ XFD_ANDSET(&tmp_set, &LastSelectWriteMask, &NotifyWriteFds);
+ if (XFD_ANYSET(&tmp_set))
+ someNotifyWriteReady = TRUE;
+ }
}
XFD_ANDSET(&devicesReadable, &LastSelectMask, &EnabledDevices);
@@ -307,7 +317,7 @@ WaitForSomething(int *pClientsReady)
(void *) &LastSelectMask);
XFD_ANDSET(&tmp_set, &LastSelectMask, &NotifyReadFds);
- if (XFD_ANYSET(&tmp_set))
+ if (XFD_ANYSET(&tmp_set) || someNotifyWriteReady)
HandleNotifyFds();
if (XFD_ANYSET(&devicesReadable) || XFD_ANYSET(&clientsReadable))
diff --git a/os/connection.c b/os/connection.c
index 4f2e989..4da01a6 100644
--- a/os/connection.c
+++ b/os/connection.c
@@ -124,15 +124,18 @@ static int lastfdesc; /* maximum file descriptor */
fd_set WellKnownConnections; /* Listener mask */
fd_set EnabledDevices; /* mask for input devices that are on */
fd_set NotifyReadFds; /* mask for other file descriptors */
+fd_set NotifyWriteFds; /* mask for other write file descriptors */
fd_set AllSockets; /* select on this */
fd_set AllClients; /* available clients */
fd_set LastSelectMask; /* mask returned from last select call */
+fd_set LastSelectWriteMask; /* mask returned from last select call */
fd_set ClientsWithInput; /* clients with FULL requests in buffer */
fd_set ClientsWriteBlocked; /* clients who cannot receive output */
fd_set OutputPending; /* clients with reply/event data ready to go */
int MaxClients = 0;
+int NumNotifyWriteFd; /* Number of NotifyFd members with write set */
Bool NewOutputPending; /* not yet attempted to write some new output */
-Bool AnyClientsWriteBlocked; /* true if some client blocked on write */
+Bool AnyWritesPending; /* true if some client blocked on write or NotifyFd with write */
Bool NoListenAll; /* Don't establish any listening sockets */
static Bool RunFromSmartParent; /* send SIGUSR1 to parent process */
@@ -969,8 +972,8 @@ CloseDownFileDescriptor(OsCommPtr oc)
FD_CLR(connection, &SavedClientsWithInput);
}
FD_CLR(connection, &ClientsWriteBlocked);
- if (!XFD_ANYSET(&ClientsWriteBlocked))
- AnyClientsWriteBlocked = FALSE;
+ if (!XFD_ANYSET(&ClientsWriteBlocked) && NumNotifyWriteFd == 0)
+ AnyWritesPending = FALSE;
FD_CLR(connection, &OutputPending);
}
@@ -1112,6 +1115,7 @@ InitNotifyFds(void)
RemoveNotifyFd(s->fd);
xorg_list_init(¬ify_fds);
+ NumNotifyWriteFd = 0;
been_here = 1;
}
@@ -1153,6 +1157,20 @@ SetNotifyFd(int fd, NotifyFdProcPtr notify, int mask, void *data)
FD_CLR(fd, &NotifyReadFds);
}
}
+
+ if (changes & X_NOTIFY_WRITE) {
+ if (mask & X_NOTIFY_WRITE) {
+ FD_SET(fd, &NotifyWriteFds);
+ if (!NumNotifyWriteFd++)
+ AnyWritesPending = TRUE;
+ } else {
+ FD_CLR(fd, &NotifyWriteFds);
+ if (!--NumNotifyWriteFd)
+ if (!XFD_ANYSET(&ClientsWriteBlocked))
+ AnyWritesPending = FALSE;
+ }
+ }
+
if (mask == 0) {
xorg_list_del(&n->list);
free(n);
@@ -1174,12 +1192,16 @@ SetNotifyFd(int fd, NotifyFdProcPtr notify, int mask, void *data)
void
HandleNotifyFds(void)
{
- struct notify_fd *s, *next;
-
- xorg_list_for_each_entry_safe(s, next, ¬ify_fds, list) {
- if (FD_ISSET(s->fd, &LastSelectMask)) {
- s->notify(s->fd, X_NOTIFY_READ, s->data);
- }
+ struct notify_fd *n, *next;
+
+ xorg_list_for_each_entry_safe(n, next, ¬ify_fds, list) {
+ int ready = 0;
+ if ((n->mask & X_NOTIFY_READ) && FD_ISSET(n->fd, &LastSelectMask))
+ ready |= X_NOTIFY_READ;
+ if ((n->mask & X_NOTIFY_WRITE) & FD_ISSET(n->fd, &LastSelectWriteMask))
+ ready |= X_NOTIFY_WRITE;
+ if (ready != 0)
+ n->notify(n->fd, ready, n->data);
}
}
diff --git a/os/io.c b/os/io.c
index 864f44a..5c2b787 100644
--- a/os/io.c
+++ b/os/io.c
@@ -946,7 +946,7 @@ FlushClient(ClientPtr who, OsCommPtr oc, const void *__extraBuf, int extraCount)
and not ready to accept more. Make a note of it and buffer
the rest. */
FD_SET(connection, &ClientsWriteBlocked);
- AnyClientsWriteBlocked = TRUE;
+ AnyWritesPending = TRUE;
if (written < oco->count) {
if (written > 0) {
@@ -1009,10 +1009,10 @@ FlushClient(ClientPtr who, OsCommPtr oc, const void *__extraBuf, int extraCount)
/* everything was flushed out */
oco->count = 0;
/* check to see if this client was write blocked */
- if (AnyClientsWriteBlocked) {
+ if (AnyWritesPending) {
FD_CLR(oc->fd, &ClientsWriteBlocked);
- if (!XFD_ANYSET(&ClientsWriteBlocked))
- AnyClientsWriteBlocked = FALSE;
+ if (!XFD_ANYSET(&ClientsWriteBlocked) && NumNotifyWriteFd == 0)
+ AnyWritesPending = FALSE;
}
if (oco->size > BUFWATERMARK) {
free(oco->buf);
diff --git a/os/osdep.h b/os/osdep.h
index 2bfc783..2fbfc48 100644
--- a/os/osdep.h
+++ b/os/osdep.h
@@ -168,9 +168,11 @@ extern void HandleNotifyFds(void);
extern fd_set AllSockets;
extern fd_set AllClients;
extern fd_set LastSelectMask;
+extern fd_set LastSelectWriteMask;
extern fd_set WellKnownConnections;
extern fd_set EnabledDevices;
extern fd_set NotifyReadFds;
+extern fd_set NotifyWriteFds;
extern fd_set ClientsWithInput;
extern fd_set ClientsWriteBlocked;
extern fd_set OutputPending;
@@ -185,7 +187,8 @@ extern void ClearConnectionTranslation(void);
#endif
extern Bool NewOutputPending;
-extern Bool AnyClientsWriteBlocked;
+extern Bool AnyWritesPending;
+extern Bool NumNotifyWriteFd;
extern WorkQueuePtr workQueue;
--
2.6.1
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