From 373fa7c2acfcaffd2c8c4ed89d1311d4bc757c1b Mon Sep 17 00:00:00 2001
From: Christian Schwarz <me@cschwarz.com>
Date: Mon, 9 Oct 2023 20:21:22 +0000
Subject: [PATCH] origin/problame/page-cache-forward-progress/3: trace spans
 and events only for tests

---
 libs/nostarve_queue/src/lib.rs | 8 ++++++++
 pageserver/src/page_cache.rs   | 4 ++--
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/libs/nostarve_queue/src/lib.rs b/libs/nostarve_queue/src/lib.rs
index 885e77c45b..57cd7f7b43 100644
--- a/libs/nostarve_queue/src/lib.rs
+++ b/libs/nostarve_queue/src/lib.rs
@@ -82,6 +82,7 @@ impl<T> Queue<T> {
         }
     }
     pub fn begin(&self) -> Result<Position<T>, ()> {
+        #[cfg(test)]
         tracing::trace!("get in line locking inner");
         let mut inner = self.inner.lock().unwrap();
         inner.integrity_check();
@@ -102,10 +103,12 @@ impl<T> Queue<T> {
 
 impl<'q, T> Position<'q, T> {
     pub fn complete_and_wait(self, datum: T) -> impl std::future::Future<Output = T> + 'q {
+        #[cfg(test)]
         tracing::trace!("found victim locking waiters");
         let mut inner = self.queue.inner.lock().unwrap();
         inner.integrity_check();
         let winner_idx = inner.waiters.pop_front().expect("we put ourselves in");
+        #[cfg(test)]
         tracing::trace!(winner_idx, "putting victim into next waiters slot");
         let winner_slot = inner.slots[winner_idx].as_mut().unwrap();
         let prev = winner_slot.1.replace(datum);
@@ -114,6 +117,7 @@ impl<'q, T> Position<'q, T> {
             "ensure we didn't mess up this simple ring buffer structure"
         );
         if let Some(waker) = winner_slot.0.take() {
+            #[cfg(test)]
             tracing::trace!(winner_idx, "waking up winner");
             waker.wake()
         }
@@ -129,6 +133,7 @@ impl<'q, T> Position<'q, T> {
         poll_fn(move |cx| {
             let my_waitslot_idx = self.idx;
             poll_num += 1;
+            #[cfg(test)]
             tracing::trace!(poll_num, "poll_fn locking waiters");
             let mut inner = self.queue.inner.lock().unwrap();
             inner.integrity_check();
@@ -139,6 +144,7 @@ impl<'q, T> Position<'q, T> {
             //     my_waitslot.1.is_some()
             // );
             if let Some(res) = my_waitslot.1.take() {
+                #[cfg(test)]
                 tracing::trace!(poll_num, "have cache slot");
                 // above .take() resets the waiters slot to None
                 debug_assert!(my_waitslot.0.is_none());
@@ -157,9 +163,11 @@ impl<'q, T> Position<'q, T> {
                 .unwrap_or(false)
             {
                 let prev = my_waitslot.0.replace(cx.waker().clone());
+                #[cfg(test)]
                 tracing::trace!(poll_num, prev_is_some = prev.is_some(), "updating waker");
             }
             inner.integrity_check();
+            #[cfg(test)]
             tracing::trace!(poll_num, "waiting to be woken up");
             Poll::Pending
         })
diff --git a/pageserver/src/page_cache.rs b/pageserver/src/page_cache.rs
index 95c8a817c3..8d1010d29d 100644
--- a/pageserver/src/page_cache.rs
+++ b/pageserver/src/page_cache.rs
@@ -443,7 +443,7 @@ impl PageCache {
     ///
     /// Store an image of the given page in the cache.
     ///
-    #[instrument(skip_all, level = "trace", fields(%key, %lsn))]
+    #[cfg_attr(test, instrument(skip_all, level = "trace", fields(%key, %lsn)))]
     pub async fn memorize_materialized_page(
         &'static self,
         tenant_id: TenantId,
@@ -536,7 +536,7 @@ impl PageCache {
 
     // Section 1.2: Public interface functions for working with immutable file pages.
 
-    #[instrument(skip_all, level = "trace", fields(?file_id, ?blkno))]
+    #[cfg_attr(test, instrument(skip_all, level = "trace", fields(?file_id, ?blkno)))]
     pub async fn read_immutable_buf(
         &'static self,
         file_id: FileId,