# HG changeset patch
# User Kim Alvefur <zash@zash.se>
# Date 1628939249 -7200
# Node ID 3f1450ec37f4c388cea2868884525f06f3467f5a
# Parent  59cf555b4698c720febb2d81a122c83f15091bdd
net.server_epoll: Improve efficiency of opportunistic writes

Should prevent further opportunistic write attempts after the kernel
buffers are full and stops accepting writes.

When combined with `keep_buffers = false` it should stop it from
repeatedly recreating the buffer table and concatenating it back into a
string when there's a lot to write.

diff -r 59cf555b4698 -r 3f1450ec37f4 net/server_epoll.lua
--- a/net/server_epoll.lua	Thu Aug 12 19:34:17 2021 +0200
+++ b/net/server_epoll.lua	Sat Aug 14 13:07:29 2021 +0200
@@ -484,6 +484,7 @@
 		end
 	end
 	local ok, err, partial = self.conn:send(data);
+	self._writable = ok;
 	if ok then
 		self:set(nil, false);
 		if cfg.keep_buffers and type(buffer) == "table" then
@@ -539,7 +540,7 @@
 		self.writebuffer = data;
 	end
 	if not self._write_lock then
-		if cfg.opportunistic_writes and not self._opportunistic_write then
+		if self._writable and cfg.opportunistic_writes and not self._opportunistic_write then
 			self._opportunistic_write = true;
 			local ret, err = self:onwritable();
 			self._opportunistic_write = nil;
@@ -745,6 +746,7 @@
 	local client = wrapsocket(conn, self, nil, self.listeners);
 	client:debug("New connection %s on server %s", client, self);
 	client:defaultoptions();
+	client._writable = cfg.opportunistic_writes;
 	if self.tls_direct then
 		client:add(true, true);
 		client:inittls(self.tls_ctx, true);