Less verbose logging (#1756)

Simplifies a few logs from O(N) to O(1)

Author: mkeeter

upstairs/src/client.rs

@@ -1,11 +1,11 @@
 // Copyright 2023 Oxide Computer Company
 use crate::{
-    cdt, integrity_hash, io_limits::ClientIOLimits, live_repair::ExtentInfo,
-    upstairs::UpstairsConfig, upstairs::UpstairsState, ClientIOStateCount,
-    ClientId, ConnectionMode, CrucibleDecoder, CrucibleError, DownstairsIO,
-    DsState, DsStateData, EncryptionContext, IOState, IOop, JobId, Message,
-    RawReadResponse, ReconcileIO, ReconcileIOState, RegionDefinitionStatus,
-    RegionMetadata,
+    cdt, format_job_list, integrity_hash, io_limits::ClientIOLimits,
+    live_repair::ExtentInfo, upstairs::UpstairsConfig, upstairs::UpstairsState,
+    ClientIOStateCount, ClientId, ConnectionMode, CrucibleDecoder,
+    CrucibleError, DownstairsIO, DsState, DsStateData, EncryptionContext,
+    IOState, IOop, JobId, Message, RawReadResponse, ReconcileIO,
+    ReconcileIOState, RegionDefinitionStatus, RegionMetadata,
 };
 use crucible_common::{x509::TLSContext, NegotiationError, VerboseTimeout};
 use crucible_protocol::{
@@ -399,7 +399,8 @@ impl DownstairsClient {
                     });
                     info!(
                         self.log,
-                        " {} final dependency list {:?}", ds_id, dependencies
+                        " {ds_id} final dependency list {}",
+                        format_job_list(dependencies),
                     );
                 }
             }
@@ -2277,8 +2278,22 @@ impl ClientIoTask {
                 "client task could not reply to main task; shutting down?"
             );
         }
-        while let Some(v) = self.request_rx.recv().await {
-            warn!(self.log, "exiting client task is ignoring message {v}");
+        if let Some(v) = self.request_rx.recv().await {
+            // Flush out the queue, waiting for the other side to close the
+            // channel before dropping it ourself.
+            let mut n = 0;
+            while self.request_rx.recv().await.is_some() {
+                n += 1;
+            }
+            warn!(
+                self.log,
+                "exiting client task is ignoring message {v}{}",
+                if n > 0 {
+                    format!(" and {n} other messages")
+                } else {
+                    "".to_owned()
+                }
+            );
         }
         info!(self.log, "client task is exiting");
     }

upstairs/src/downstairs.rs

@@ -13,6 +13,7 @@ use crate::{
         ClientRunResult, ClientStopReason, DownstairsClient, EnqueueResult,
         NegotiationStateData, ShouldSendError,
     },
+    format_job_list,
     guest::GuestBlockRes,
     io_limits::{IOLimitGuard, IOLimits},
     live_repair::ExtentInfo,
@@ -1459,13 +1460,13 @@ impl Downstairs {
 
         info!(
             self.log,
-            "RE:{} repair extent with ids {},{},{},{} deps:{:?}",
+            "RE:{} repair extent with ids {},{},{},{} deps:{}",
             extent,
             close_id,
             repair_id,
             noop_id,
             reopen_id,
-            close_deps,
+            format_job_list(&close_deps),
         );
 
         let repair = self.repair.as_mut().unwrap(); // reborrow

upstairs/src/lib.rs

@@ -1595,6 +1595,15 @@ pub struct DtraceInfo {
     pub ds_ro_lr_skipped: [usize; 3],
 }
 
+pub(crate) fn format_job_list(ids: &[JobId]) -> String {
+    let n = ids.len();
+    if n < 4 {
+        format!("[{ids:?}]")
+    } else {
+        format!("[{:?}, ... {:?}] ({n} total)", ids[0], ids[n - 1],)
+    }
+}
+
 /*
  * This is the main upstairs task that starts all the other async tasks.
  *