Fork Puma gem

This makes us to switch to use Puma from:
- https://gitlab.com/gitlab-org/gitlab-puma
- https://gitlab.com/gitlab-org/gitlab-puma_worker_killer

This is needed to test a latest latency improvements
for Puma to improve, Puma scheduling mechanism.

This is meant to be temporary as part of effort to upstream
the https://github.com/puma/puma/pull/2079

Gemfile

@@ -170,8 +170,8 @@ group :unicorn do
 end
 
 group :puma do
-  gem 'puma', '~> 4.3.0', require: false
-  gem 'puma_worker_killer', '~> 0.1.1', require: false
+  gem 'gitlab-puma', '~> 4.3.1.gitlab.2', require: false
+  gem 'gitlab-puma_worker_killer', '~> 0.1.1.gitlab.1', require: false
   gem 'rack-timeout', require: false
 end
 

Gemfile.lock

@@ -372,6 +372,11 @@ GEM
     gitlab-license (1.0.0)
     gitlab-markup (1.7.0)
     gitlab-net-dns (0.9.1)
+    gitlab-puma (4.3.1.gitlab.2)
+      nio4r (~> 2.0)
+    gitlab-puma_worker_killer (0.1.1.gitlab.1)
+      get_process_mem (~> 0.2)
+      gitlab-puma (>= 2.7, < 5)
     gitlab-sidekiq-fetcher (0.5.2)
       sidekiq (~> 5)
     gitlab-styles (2.8.0)
@@ -619,7 +624,7 @@ GEM
     net-ntp (2.1.3)
     net-ssh (5.2.0)
     netrc (0.11.0)
-    nio4r (2.3.1)
+    nio4r (2.5.2)
     no_proxy_fix (0.1.2)
     nokogiri (1.10.5)
       mini_portile2 (~> 2.4.0)
@@ -748,11 +753,6 @@ GEM
     pry-rails (0.3.6)
       pry (>= 0.10.4)
     public_suffix (3.1.1)
-    puma (4.3.1)
-      nio4r (~> 2.0)
-    puma_worker_killer (0.1.1)
-      get_process_mem (~> 0.2)
-      puma (>= 2.7, < 5)
     pyu-ruby-sasl (0.0.3.3)
     raabro (1.1.6)
     rack (2.0.7)
@@ -1200,6 +1200,8 @@ DEPENDENCIES
   gitlab-license (~> 1.0)
   gitlab-markup (~> 1.7.0)
   gitlab-net-dns (~> 0.9.1)
+  gitlab-puma (~> 4.3.1.gitlab.2)
+  gitlab-puma_worker_killer (~> 0.1.1.gitlab.1)
   gitlab-sidekiq-fetcher (= 0.5.2)
   gitlab-styles (~> 2.7)
   gitlab_chronic_duration (~> 0.10.6.2)
@@ -1280,8 +1282,6 @@ DEPENDENCIES
   prometheus-client-mmap (~> 0.9.10)
   pry-byebug (~> 3.5.1)
   pry-rails (~> 0.3.4)
-  puma (~> 4.3.0)
-  puma_worker_killer (~> 0.1.1)
   rack (~> 2.0.7)
   rack-attack (~> 6.2.0)
   rack-cors (~> 1.0.0)

changelogs/unreleased/fork-puma-gem.yml

+---
+title: Fork Puma to validate scheduler fixes
+merge_request: 21547
+author:
+type: performance