[PATCH v3] socket: fix polling in case of spurious wakeup
Georgy Kirichenko
georgy at tarantool.org
Wed Oct 10 13:13:04 MSK 2018
socket_writable/socket_readable handles socket.iowait spurious wakeup
until event is happened or timeout is exceeded.
Closes: #3344
---
https://github.com/tarantool/tarantool/issues/3344
https://github.com/tarantool/tarantool/tree/g.kirichenko/gh-3344-socket-io-spurios-wakeup
Changes in v3:
- Fixes according to Vova's review
Changes in v2:
- Fixes according to Vlad's review
src/lua/socket.lua | 46 +++++++++++-----------------
test/app/socket.result | 66 ++++++++++++++++++++++++++++++++++++++++
test/app/socket.test.lua | 28 +++++++++++++++++
3 files changed, 112 insertions(+), 28 deletions(-)
diff --git a/src/lua/socket.lua b/src/lua/socket.lua
index 8f5e2926b..7f9b40fb1 100644
--- a/src/lua/socket.lua
+++ b/src/lua/socket.lua
@@ -332,12 +332,17 @@ local function do_wait(self, what, timeout)
self._errno = nil
timeout = timeout or TIMEOUT_INFINITY
- local res = internal.iowait(fd, what, timeout)
- if res == 0 then
- self._errno = boxerrno.ETIMEDOUT
- return 0
- end
- return res
+ repeat
+ local started = fiber.clock()
+ local events = internal.iowait(fd, what, timeout)
+ fiber.testcancel()
+ if events ~= 0 and events ~= '' then
+ return events
+ end
+ timeout = timeout - (fiber.clock() - started)
+ until timeout < 0
+ self._errno = boxerrno.ETIMEDOUT
+ return 0
end
local function socket_readable(self, timeout)
@@ -666,9 +671,8 @@ local function read(self, limit, timeout, check, ...)
return data
end
- while timeout > 0 do
- local started = fiber.clock()
-
+ local deadline = fiber.clock() + timeout
+ repeat
assert(rbuf:size() < limit)
local to_read = math.min(limit - rbuf:size(), buffer.READAHEAD)
local data = rbuf:reserve(to_read)
@@ -692,16 +696,7 @@ local function read(self, limit, timeout, check, ...)
elseif not errno_is_transient[self._errno] then
return nil
end
-
- if not socket_readable(self, timeout) then
- return nil
- end
- if timeout <= 0 then
- break
- end
- timeout = timeout - ( fiber.clock() - started )
- end
- self._errno = boxerrno.ETIMEDOUT
+ until not socket_readable(self, deadline - fiber.clock())
return nil
end
@@ -739,8 +734,8 @@ local function socket_write(self, octets, timeout)
return 0
end
- local started = fiber.clock()
- while true do
+ local deadline = fiber.clock() + timeout
+ repeat
local written = syswrite(self, p, e - p)
if written == 0 then
return p - s -- eof
@@ -754,11 +749,8 @@ local function socket_write(self, octets, timeout)
return nil
end
- timeout = timeout - (fiber.clock() - started)
- if timeout <= 0 or not socket_writable(self, timeout) then
- break
- end
- end
+ until not socket_writable(self, deadline - fiber.clock())
+ return nil
end
local function socket_send(self, octets, flags)
@@ -999,8 +991,6 @@ local function socket_tcp_connect(s, address, port, timeout)
-- conditions appart SO_ERROR must be consulted (man connect).
if socket_writable(s, timeout) then
s._errno = socket_getsockopt(s, 'SOL_SOCKET', 'SO_ERROR')
- else
- s._errno = boxerrno.ETIMEDOUT
end
if s._errno ~= 0 then
return nil
diff --git a/test/app/socket.result b/test/app/socket.result
index 729c1eb3f..2f002a37e 100644
--- a/test/app/socket.result
+++ b/test/app/socket.result
@@ -2779,6 +2779,72 @@ listening_socket:close()
---
- true
...
+--gh-3344 connection should not fail is there is a spurious wakeup for io fiber
+test_run:cmd("setopt delimiter ';'")
+---
+- true
+...
+echo_fiber = nil
+server = socket.tcp_server('localhost', 0, { handler = function(s)
+ echo_fiber = fiber.self()
+ while true do
+ local b = s:read(1, 0.1)
+ if b ~= nil then
+ s:write(b)
+ end
+ end
+end, name = 'echoserv'});
+---
+...
+test_run:cmd("setopt delimiter ''");
+---
+- true
+...
+addr = server:name()
+---
+...
+client = socket.tcp_connect(addr.host, addr.port)
+---
+...
+echo_fiber ~= nil
+---
+- true
+...
+client:write('hello')
+---
+- 5
+...
+client:read(5, 0.1) == 'hello'
+---
+- true
+...
+-- send spurious wakeup
+fiber.wakeup(echo_fiber)
+---
+...
+fiber.sleep(0)
+---
+...
+client:write('world')
+---
+- 5
+...
+client:read(5, 0.1) == 'world'
+---
+- true
+...
+-- cancel fiber
+fiber.cancel(echo_fiber)
+---
+...
+client:read(1, 0.1) == ''
+---
+- true
+...
+server:close()
+---
+- true
+...
test_run:cmd("clear filter")
---
- true
diff --git a/test/app/socket.test.lua b/test/app/socket.test.lua
index 9b896522b..c0b001449 100644
--- a/test/app/socket.test.lua
+++ b/test/app/socket.test.lua
@@ -939,4 +939,32 @@ receiving_socket:close()
sending_socket:close()
listening_socket:close()
+--gh-3344 connection should not fail is there is a spurious wakeup for io fiber
+test_run:cmd("setopt delimiter ';'")
+echo_fiber = nil
+server = socket.tcp_server('localhost', 0, { handler = function(s)
+ echo_fiber = fiber.self()
+ while true do
+ local b = s:read(1, 0.1)
+ if b ~= nil then
+ s:write(b)
+ end
+ end
+end, name = 'echoserv'});
+test_run:cmd("setopt delimiter ''");
+addr = server:name()
+client = socket.tcp_connect(addr.host, addr.port)
+echo_fiber ~= nil
+client:write('hello')
+client:read(5, 0.1) == 'hello'
+-- send spurious wakeup
+fiber.wakeup(echo_fiber)
+fiber.sleep(0)
+client:write('world')
+client:read(5, 0.1) == 'world'
+-- cancel fiber
+fiber.cancel(echo_fiber)
+client:read(1, 0.1) == ''
+server:close()
+
test_run:cmd("clear filter")
--
2.19.1
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