From 4dcd2caa9d7691d6a4f1d3fc0a0a4b54ac6fad6b Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Fri, 29 Dec 2023 17:44:18 +0000 Subject: middleware: reuse inet_diag netlink socket Eric Wong wrote: > I'll squash this in for fork+preload safety. I forget there are multithreaded servers using this :x ------8<----- Subject: [PATCH v3] middleware: reuse inet_diag netlink socket No point in constantly allocating and deallocating FDs (and Ruby IO objects) when reusing them is supported. However, we must guard it against parallel callers since linux_inet_diag.c::diag releases the GVL while calling sendmsg(2) and recvmsg(2), so it's possible two Ruby threads can end up crossing streams if the middlware is used with a multi-threaded server. AFAIK, Raindrops::Middleware isn't a heavily-trafficked endpoint, so saving FDs and avoiding thread specific data is preferable for memory-constrained systems I use. --- lib/raindrops/middleware.rb | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'lib') diff --git a/lib/raindrops/middleware.rb b/lib/raindrops/middleware.rb index d5e3927..20e573c 100644 --- a/lib/raindrops/middleware.rb +++ b/lib/raindrops/middleware.rb @@ -1,5 +1,6 @@ # -*- encoding: binary -*- require 'raindrops' +require 'thread' # Raindrops::Middleware is Rack middleware that allows snapshotting # current activity from an HTTP request. For all operating systems, @@ -93,11 +94,12 @@ class Raindrops::Middleware @app = app @stats = opts[:stats] || Stats.new @path = opts[:path] || "/_raindrops" + @mtx = Mutex.new tmp = opts[:listeners] if tmp.nil? && defined?(Unicorn) && Unicorn.respond_to?(:listener_names) tmp = Unicorn.listener_names end - @tcp = @unix = nil + @nl_sock = @tcp = @unix = nil if tmp @tcp = tmp.grep(/\A.+:\d+\z/) @@ -129,9 +131,12 @@ class Raindrops::Middleware "writing: #{@stats.writing}\n" if defined?(Raindrops::Linux.tcp_listener_stats) - Raindrops::Linux.tcp_listener_stats(@tcp).each do |addr,stats| - body << "#{addr} active: #{stats.active}\n" \ - "#{addr} queued: #{stats.queued}\n" + @mtx.synchronize do + @nl_sock ||= Raindrops::InetDiagSocket.new + Raindrops::Linux.tcp_listener_stats(@tcp, @nl_sock).each do |addr,stats| + body << "#{addr} active: #{stats.active}\n" \ + "#{addr} queued: #{stats.queued}\n" + end end if @tcp Raindrops::Linux.unix_listener_stats(@unix).each do |addr,stats| body << "#{addr} active: #{stats.active}\n" \ -- cgit v1.2.3-24-ge0c7