Files
poky/meta/recipes-devtools/pseudo/files/toomanyfiles.patch
Richard Purdie 8cbdc270c9 pseudo: Handle too many files deadlock
If we have large amounts of parallelism, pseudo can end up with too
many open connections and will no longer accept further connections,
hanging. This patch works around that by closing some clients, allowing
turnover of connections and unblocking the system. The downside is a small
but theoretical window of data loss. This is likely better than locking
up entirely though. Discussions with Peter are onging about how we could
better fix this.

(From OE-Core rev: f3589f154dad1c92e599737623d392508810ae7e)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
2017-06-22 09:16:00 +01:00

63 lines
2.2 KiB
Diff

Currently if we max out the maximum number of files, pseudo can deadlock, unable to
accept new connections yet unable to move forward and unblock the other processes
waiting either.
Rather than hang, when this happens, close out inactive connections, allowing us
to accept the new ones. The disconnected clients will simply reconnect. There is
a small risk of data loss here sadly but its better than hanging.
RP
2017/4/25
Upstream-Status: Pending [Peter is aware of the issue]
Index: pseudo-1.8.2/pseudo_server.c
===================================================================
--- pseudo-1.8.2.orig/pseudo_server.c
+++ pseudo-1.8.2/pseudo_server.c
@@ -581,6 +581,7 @@ pseudo_server_loop(void) {
int rc;
int fd;
int loop_timeout = pseudo_server_timeout;
+ int hitmaxfiles;
clients = malloc(16 * sizeof(*clients));
@@ -597,6 +598,7 @@ pseudo_server_loop(void) {
active_clients = 1;
max_clients = 16;
highest_client = 0;
+ hitmaxfiles = 0;
pseudo_debug(PDBGF_SERVER, "server loop started.\n");
if (listen_fd < 0) {
@@ -663,10 +665,18 @@ pseudo_server_loop(void) {
message_time.tv_usec -= 1000000;
++message_time.tv_sec;
}
+ } else if (hitmaxfiles) {
+ /* In theory there is a potential race here where if we close a client,
+ it may have sent us a fastop message which we don't act upon.
+ If we don't close a filehandle we'll loop indefinitely thought.
+ Only close one per loop iteration in the interests of caution */
+ close_client(i);
+ hitmaxfiles = 0;
}
if (die_forcefully)
break;
}
+ hitmaxfiles = 0;
if (!die_forcefully &&
(FD_ISSET(clients[0].fd, &events) ||
FD_ISSET(clients[0].fd, &reads))) {
@@ -688,6 +698,9 @@ pseudo_server_loop(void) {
*/
pseudo_server_timeout = DEFAULT_PSEUDO_SERVER_TIMEOUT;
die_peacefully = 0;
+ } else if (errno == EMFILE) {
+ hitmaxfiles = 1;
+ pseudo_debug(PDBGF_SERVER, "Hit max open files, dropping a client.\n");
}
}
pseudo_debug(PDBGF_SERVER, "server loop complete [%d clients left]\n", active_clients);