[oe-commits] [openembedded-core] 15/19: pseudo: use epoll API on Linux
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commit 856414d1253d40045f6b9e507e6f7b19e65a7c94
Author: Alexander Kanavin <alexander.kanavin at linux.intel.com>
AuthorDate: Fri Sep 22 18:18:46 2017 +0300
pseudo: use epoll API on Linux
The idea came up here:
https://bugzilla.yoctoproject.org/show_bug.cgi?id=11309
and here:
http://lists.openembedded.org/pipermail/openembedded-core/2017-August/141491.html
Signed-off-by: Alexander Kanavin <alexander.kanavin at linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>
---
.../pseudo/files/0001-Use-epoll-API-on-Linux.patch | 292 +++++++++++++++++++++
meta/recipes-devtools/pseudo/pseudo_1.8.2.bb | 1 +
2 files changed, 293 insertions(+)
diff --git a/meta/recipes-devtools/pseudo/files/0001-Use-epoll-API-on-Linux.patch b/meta/recipes-devtools/pseudo/files/0001-Use-epoll-API-on-Linux.patch
new file mode 100644
index 0000000..42557b1
--- /dev/null
+++ b/meta/recipes-devtools/pseudo/files/0001-Use-epoll-API-on-Linux.patch
@@ -0,0 +1,292 @@
+From 9e407e0be01695e7b927f5820ade87ee9602c248 Mon Sep 17 00:00:00 2001
+From: Alexander Kanavin <alex.kanavin at gmail.com>
+Date: Fri, 15 Sep 2017 17:00:14 +0300
+Subject: [PATCH] Use epoll API on Linux
+
+Also a couple of other modifications due to epoll having
+a different approach to how the working set of fds is defined
+and used:
+1) open_client() returns an index into the array of clients
+2) close_client() has a protection against being called twice
+with the same client (which would mess up the active_clients
+counter)
+
+Upstream-Status: Submitted [Seebs CC'd by email]
+Signed-off-by: Alexander Kanavin <alex.kanavin at gmail.com>
+
+---
+ enums/exit_status.in | 3 +
+ pseudo_server.c | 189 ++++++++++++++++++++++++++++++++++++++++++++++++++-
+ 2 files changed, 190 insertions(+), 2 deletions(-)
+
+diff --git a/enums/exit_status.in b/enums/exit_status.in
+index 6be44d3..88f94cd 100644
+--- a/enums/exit_status.in
++++ b/enums/exit_status.in
+@@ -18,3 +18,6 @@ listen_fd, "server loop had no valid listen fd"
+ pseudo_loaded, "server couldn't get out of pseudo environment"
+ pseudo_prefix, "couldn't get valid pseudo prefix"
+ pseudo_invocation, "invalid server command arguments"
++epoll_create, "epoll_create() failed"
++epoll_ctl, "epoll_ctl() failed"
++
+diff --git a/pseudo_server.c b/pseudo_server.c
+index ff16efd..14d34de 100644
+--- a/pseudo_server.c
++++ b/pseudo_server.c
+@@ -40,6 +40,12 @@
+ #include "pseudo_client.h"
+ #include "pseudo_db.h"
+
++// This has to come after pseudo includes, as that's where PSEUDO_PORT defines are
++#ifdef PSEUDO_PORT_LINUX
++#include <sys/epoll.h>
++#endif
++
++
+ static int listen_fd = -1;
+
+ typedef struct {
+@@ -59,6 +65,7 @@ static int active_clients = 0, highest_client = 0, max_clients = 0;
+
+ #define LOOP_DELAY 2
+ #define DEFAULT_PSEUDO_SERVER_TIMEOUT 30
++#define EPOLL_MAX_EVENTS 10
+ int pseudo_server_timeout = DEFAULT_PSEUDO_SERVER_TIMEOUT;
+ static int die_peacefully = 0;
+ static int die_forcefully = 0;
+@@ -80,6 +87,9 @@ quit_now(int signal) {
+ static int messages = 0, responses = 0;
+ static struct timeval message_time = { .tv_sec = 0 };
+
++#ifdef PSEUDO_PORT_LINUX
++static void pseudo_server_loop_epoll(void);
++#endif
+ static void pseudo_server_loop(void);
+
+ /* helper function to make a directory, just like mkdir -p.
+@@ -369,12 +379,16 @@ pseudo_server_start(int daemonize) {
+ kill(ppid, SIGUSR1);
+ }
+ }
++#ifdef PSEUDO_PORT_LINUX
++ pseudo_server_loop_epoll();
++#else
+ pseudo_server_loop();
++#endif
+ return 0;
+ }
+
+ /* mess with internal tables as needed */
+-static void
++static unsigned int
+ open_client(int fd) {
+ pseudo_client_t *new_clients;
+ int i;
+@@ -390,7 +404,7 @@ open_client(int fd) {
+ ++active_clients;
+ if (i > highest_client)
+ highest_client = i;
+- return;
++ return i;
+ }
+ }
+
+@@ -414,9 +428,11 @@ open_client(int fd) {
+
+ max_clients += 16;
+ ++active_clients;
++ return max_clients - 16;
+ } else {
+ pseudo_diag("error allocating new client, fd %d\n", fd);
+ close(fd);
++ return 0;
+ }
+ }
+
+@@ -433,6 +449,10 @@ close_client(int client) {
+ client, highest_client);
+ return;
+ }
++ if (clients[client].fd == -1) {
++ pseudo_debug(PDBGF_SERVER, "client %d already closed\n", client);
++ return;
++ }
+ close(clients[client].fd);
+ clients[client].fd = -1;
+ free(clients[client].tag);
+@@ -566,6 +586,171 @@ serve_client(int i) {
+ }
+ }
+
++#ifdef PSEUDO_PORT_LINUX
++static void pseudo_server_loop_epoll(void)
++{
++ struct sockaddr_un client;
++ socklen_t len;
++ int i;
++ int rc;
++ int fd;
++ int timeout;
++ struct epoll_event ev, events[EPOLL_MAX_EVENTS];
++ int loop_timeout = pseudo_server_timeout;
++
++ clients = malloc(16 * sizeof(*clients));
++
++ clients[0].fd = listen_fd;
++ clients[0].pid = getpid();
++
++ for (i = 1; i < 16; ++i) {
++ clients[i].fd = -1;
++ clients[i].pid = 0;
++ clients[i].tag = NULL;
++ clients[i].program = NULL;
++ }
++
++ active_clients = 1;
++ max_clients = 16;
++ highest_client = 0;
++
++ pseudo_debug(PDBGF_SERVER, "server loop started.\n");
++ if (listen_fd < 0) {
++ pseudo_diag("got into loop with no valid listen fd.\n");
++ exit(PSEUDO_EXIT_LISTEN_FD);
++ }
++
++ timeout = LOOP_DELAY * 1000;
++
++ int epollfd = epoll_create1(0);
++ if (epollfd == -1) {
++ pseudo_diag("epoll_create1() failed.\n");
++ exit(PSEUDO_EXIT_EPOLL_CREATE);
++ }
++ ev.events = EPOLLIN;
++ ev.data.u64 = 0;
++ if (epoll_ctl(epollfd, EPOLL_CTL_ADD, clients[0].fd, &ev) == -1) {
++ pseudo_diag("epoll_ctl() failed with listening socket.\n");
++ exit(PSEUDO_EXIT_EPOLL_CTL);
++ }
++
++ pdb_log_msg(SEVERITY_INFO, NULL, NULL, NULL, "server started (pid %d)", getpid());
++
++ for (;;) {
++ rc = epoll_wait(epollfd, events, EPOLL_MAX_EVENTS, timeout);
++ if (rc == 0 || (rc == -1 && errno == EINTR)) {
++ /* If there's no clients, start timing out. If there
++ * are active clients, never time out.
++ */
++ if (active_clients == 1) {
++ loop_timeout -= LOOP_DELAY;
++ /* maybe flush database to disk */
++ pdb_maybe_backup();
++ if (loop_timeout <= 0) {
++ pseudo_debug(PDBGF_SERVER, "no more clients, got bored.\n");
++ die_peacefully = 1;
++ } else {
++ /* display this if not exiting */
++ pseudo_debug(PDBGF_SERVER | PDBGF_BENCHMARK, "%d messages handled in %.4f seconds, %d responses\n",
++ messages,
++ (double) message_time.tv_sec +
++ (double) message_time.tv_usec / 1000000.0,
++ responses);
++ }
++ }
++ } else if (rc > 0) {
++ loop_timeout = pseudo_server_timeout;
++ for (i = 0; i < rc; ++i) {
++ if (clients[events[i].data.u64].fd == listen_fd) {
++ if (!die_forcefully) {
++ len = sizeof(client);
++ if ((fd = accept(listen_fd, (struct sockaddr *) &client, &len)) != -1) {
++ /* Don't allow clients to end up on fd 2, because glibc's
++ * malloc debug uses that fd unconditionally.
++ */
++ if (fd == 2) {
++ int newfd = fcntl(fd, F_DUPFD, 3);
++ close(fd);
++ fd = newfd;
++ }
++ pseudo_debug(PDBGF_SERVER, "new client fd %d\n", fd);
++ /* A new client implicitly cancels any
++ * previous shutdown request, or a
++ * shutdown for lack of clients.
++ */
++ pseudo_server_timeout = DEFAULT_PSEUDO_SERVER_TIMEOUT;
++ die_peacefully = 0;
++
++ ev.events = EPOLLIN;
++ ev.data.u64 = open_client(fd);
++ if (ev.data.u64 != 0 && epoll_ctl(epollfd, EPOLL_CTL_ADD, clients[ev.data.u64].fd, &ev) == -1) {
++ pseudo_diag("epoll_ctl() failed with accepted socket.\n");
++ exit(PSEUDO_EXIT_EPOLL_CTL);
++ }
++ } else if (errno == EMFILE) {
++ pseudo_debug(PDBGF_SERVER, "Hit max open files, dropping a client.\n");
++ /* 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 */
++ for (int j = 1; j <= highest_client; ++j) {
++ if (clients[j].fd != -1) {
++ close_client(j);
++ break;
++ }
++ }
++ }
++ }
++ } else {
++ struct timeval tv1, tv2;
++ int rc;
++ gettimeofday(&tv1, NULL);
++ rc = serve_client(events[i].data.u64);
++ gettimeofday(&tv2, NULL);
++ ++messages;
++ if (rc == 0)
++ ++responses;
++ message_time.tv_sec += (tv2.tv_sec - tv1.tv_sec);
++ message_time.tv_usec += (tv2.tv_usec - tv1.tv_usec);
++ if (message_time.tv_usec < 0) {
++ message_time.tv_usec += 1000000;
++ --message_time.tv_sec;
++ } else while (message_time.tv_usec > 1000000) {
++ message_time.tv_usec -= 1000000;
++ ++message_time.tv_sec;
++ }
++ }
++ if (die_forcefully)
++ break;
++ }
++ pseudo_debug(PDBGF_SERVER, "server loop complete [%d clients left]\n", active_clients);
++ } else {
++ pseudo_diag("epoll_wait failed: %s\n", strerror(errno));
++ break;
++ }
++ if (die_peacefully || die_forcefully) {
++ pseudo_debug(PDBGF_SERVER, "quitting.\n");
++ pseudo_debug(PDBGF_SERVER | PDBGF_BENCHMARK, "server %d exiting: handled %d messages in %.4f seconds\n",
++ getpid(), messages,
++ (double) message_time.tv_sec +
++ (double) message_time.tv_usec / 1000000.0);
++ pdb_log_msg(SEVERITY_INFO, NULL, NULL, NULL, "server %d exiting: handled %d messages in %.4f seconds",
++ getpid(), messages,
++ (double) message_time.tv_sec +
++ (double) message_time.tv_usec / 1000000.0);
++ /* and at this point, we'll start refusing connections */
++ close(clients[0].fd);
++ /* This is a good place to insert a delay for
++ * debugging race conditions during startup. */
++ /* usleep(300000); */
++ exit(0);
++ }
++ }
++
++}
++
++#endif
++
+ /* get clients, handle messages, shut down.
+ * This doesn't actually do any work, it just calls a ton of things which
+ * do work.
+--
+2.14.1
+
diff --git a/meta/recipes-devtools/pseudo/pseudo_1.8.2.bb b/meta/recipes-devtools/pseudo/pseudo_1.8.2.bb
index 9bcd031..81853e9 100644
--- a/meta/recipes-devtools/pseudo/pseudo_1.8.2.bb
+++ b/meta/recipes-devtools/pseudo/pseudo_1.8.2.bb
@@ -8,6 +8,7 @@ SRC_URI = "http://downloads.yoctoproject.org/releases/pseudo/${BPN}-${PV}.tar.bz
file://efe0be279901006f939cd357ccee47b651c786da.patch \
file://b6b68db896f9963558334aff7fca61adde4ec10f.patch \
file://toomanyfiles.patch \
+ file://0001-Use-epoll-API-on-Linux.patch \
"
SRC_URI[md5sum] = "7d41e72188fbea1f696c399c1a435675"
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