Remove trace_memory_allocations FF

Changelog: removed

config/feature_flags/development/trace_memory_allocations.yml

----
-name: trace_memory_allocations
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/52306
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/299524
-milestone: '13.9'
-type: development
-group: group::memory
-default_enabled: true

lib/gitlab/memory/instrumentation.rb

@@ -21,25 +21,14 @@ module Gitlab
           Thread.current.respond_to?(:memory_allocations)
       end
 
-      # This method changes a global state
-      def self.ensure_feature_flag!
+      def self.start_thread_memory_allocations
         return unless available?
 
-        enabled = Feature.enabled?(:trace_memory_allocations, default_enabled: true)
-        return if enabled == Thread.trace_memory_allocations
-
         MUTEX.synchronize do
-          # This enables or disables feature dynamically
-          # based on a feature flag
-          Thread.trace_memory_allocations = enabled
-        end
+          # This method changes a global state
+          Thread.trace_memory_allocations = true
         end
 
-      def self.start_thread_memory_allocations
-        return unless available?
-
-        ensure_feature_flag!
-
         # it will return `nil` if disabled
         Thread.current.memory_allocations
       end

spec/lib/gitlab/instrumentation_helper_spec.rb

@@ -99,23 +99,6 @@ RSpec.describe Gitlab::InstrumentationHelper do
           :mem_mallocs
         )
       end
-
-      context 'when trace_memory_allocations is disabled' do
-        before do
-          stub_feature_flags(trace_memory_allocations: false)
-          Gitlab::Memory::Instrumentation.ensure_feature_flag!
-        end
-
-        it 'does not log memory usage metrics' do
-          subject
-
-          expect(payload).not_to include(
-            :mem_objects,
-            :mem_bytes,
-            :mem_mallocs
-          )
-        end
-      end
     end
 
     context 'when load balancing is enabled' do

spec/lib/gitlab/memory/instrumentation_spec.rb

@@ -18,24 +18,8 @@ RSpec.describe Gitlab::Memory::Instrumentation do
   describe '.start_thread_memory_allocations' do
     subject { described_class.start_thread_memory_allocations }
 
-    context 'when feature flag trace_memory_allocations is enabled' do
-      before do
-        stub_feature_flags(trace_memory_allocations: true)
-      end
-
     it 'a hash is returned' do
-        is_expected.not_to be_empty
-      end
-    end
-
-    context 'when feature flag trace_memory_allocations is disabled' do
-      before do
-        stub_feature_flags(trace_memory_allocations: false)
-      end
-
-      it 'a nil is returned' do
-        is_expected.to be_nil
-      end
+      is_expected.to be_a(Hash)
     end
 
     context 'when feature is unavailable' do
@@ -63,11 +47,6 @@ RSpec.describe Gitlab::Memory::Instrumentation do
       expect(described_class).to receive(:measure_thread_memory_allocations).and_call_original
     end
 
-    context 'when feature flag trace_memory_allocations is enabled' do
-      before do
-        stub_feature_flags(trace_memory_allocations: true)
-      end
-
     it 'a hash is returned' do
       result = subject
       expect(result).to include(
@@ -77,17 +56,6 @@ RSpec.describe Gitlab::Memory::Instrumentation do
         mem_total_bytes: eq(result[:mem_bytes] + 40 * result[:mem_objects])
       )
     end
-    end
-
-    context 'when feature flag trace_memory_allocations is disabled' do
-      before do
-        stub_feature_flags(trace_memory_allocations: false)
-      end
-
-      it 'a nil is returned' do
-        is_expected.to be_nil
-      end
-    end
 
     context 'when feature is unavailable' do
       before do