PaperMC/patches/server/0591-Fix-GameProfileCache-concurrency.patch
Spottedleaf 8c5b837e05 Rework async chunk api implementation
Firstly, the old methods all routed to the CompletableFuture method.
However, the CF method could not guarantee that if the caller
was off-main that the future would be "completed" on-main. Since
the callback methods used the CF one, this meant that the callback
methods did not guarantee that the callbacks were to be called on
the main thread.

Now, all methods route to getChunkAtAsync(x, z, gen, urgent, cb)
so that the methods with the callback are guaranteed to invoke
the callback on the main thread. The CF behavior remains unchanged;
it may still appear to complete on main if invoked off-main.

Secondly, remove the scheduleOnMain invocation in the async
chunk completion. This unnecessarily delays the callback
by 1 tick.

Thirdly, add getChunksAtAsync(minX, minZ, maxX, maxZ, ...) which
will load chunks within an area. This method is provided as a helper
as keeping all chunks loaded within an area can be complicated to
implement for plugins (due to the lacking ticket API), and is
already implemented internally anyways.

Fourthly, remove the ticket addition that occured with getChunkAt
and getChunkAtAsync. The ticket addition may delay the unloading
of the chunk unnecessarily. It also fixes a very rare timing bug
where the future/callback would be completed after the chunk
unloads.
2024-11-18 23:00:59 -08:00

126 lines
6.5 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Sat, 11 Jul 2020 05:09:28 -0700
Subject: [PATCH] Fix GameProfileCache concurrency
Separate lookup and state access locks prevent lookups
from stalling simple state access/write calls
diff --git a/src/main/java/net/minecraft/server/players/GameProfileCache.java b/src/main/java/net/minecraft/server/players/GameProfileCache.java
index 774d81c702edb76a2f6184d4dc53687de6734a79..34b4166adfae8ff7d1eb73d56a72931b005330a7 100644
--- a/src/main/java/net/minecraft/server/players/GameProfileCache.java
+++ b/src/main/java/net/minecraft/server/players/GameProfileCache.java
@@ -60,6 +60,11 @@ public class GameProfileCache {
@Nullable
private Executor executor;
+ // Paper start - Fix GameProfileCache concurrency
+ protected final java.util.concurrent.locks.ReentrantLock stateLock = new java.util.concurrent.locks.ReentrantLock();
+ protected final java.util.concurrent.locks.ReentrantLock lookupLock = new java.util.concurrent.locks.ReentrantLock();
+ // Paper end - Fix GameProfileCache concurrency
+
public GameProfileCache(GameProfileRepository profileRepository, File cacheFile) {
this.profileRepository = profileRepository;
this.file = cacheFile;
@@ -67,11 +72,13 @@ public class GameProfileCache {
}
private void safeAdd(GameProfileCache.GameProfileInfo entry) {
+ try { this.stateLock.lock(); // Paper - Fix GameProfileCache concurrency
GameProfile gameprofile = entry.getProfile();
entry.setLastAccess(this.getNextOperation());
this.profilesByName.put(gameprofile.getName().toLowerCase(Locale.ROOT), entry);
this.profilesByUUID.put(gameprofile.getId(), entry);
+ } finally { this.stateLock.unlock(); } // Paper - Fix GameProfileCache concurrency
}
private static Optional<GameProfile> lookupGameProfile(GameProfileRepository repository, String name) {
@@ -128,17 +135,20 @@ public class GameProfileCache {
// Paper start
public @Nullable GameProfile getProfileIfCached(String name) {
+ try { this.stateLock.lock(); // Paper - Fix GameProfileCache concurrency
GameProfileCache.GameProfileInfo entry = this.profilesByName.get(name.toLowerCase(Locale.ROOT));
if (entry == null) {
return null;
}
entry.setLastAccess(this.getNextOperation());
return entry.getProfile();
+ } finally { this.stateLock.unlock(); } // Paper - Fix GameProfileCache concurrency
}
// Paper end
public Optional<GameProfile> get(String name) {
String s1 = name.toLowerCase(Locale.ROOT);
+ boolean stateLocked = true; try { this.stateLock.lock(); // Paper - Fix GameProfileCache concurrency
GameProfileCache.GameProfileInfo usercache_usercacheentry = (GameProfileCache.GameProfileInfo) this.profilesByName.get(s1);
boolean flag = false;
@@ -154,8 +164,12 @@ public class GameProfileCache {
if (usercache_usercacheentry != null) {
usercache_usercacheentry.setLastAccess(this.getNextOperation());
optional = Optional.of(usercache_usercacheentry.getProfile());
+ stateLocked = false; this.stateLock.unlock(); // Paper - Fix GameProfileCache concurrency
} else {
+ stateLocked = false; this.stateLock.unlock(); // Paper - Fix GameProfileCache concurrency
+ try { this.lookupLock.lock(); // Paper - Fix GameProfileCache concurrency
optional = GameProfileCache.lookupGameProfile(this.profileRepository, name); // CraftBukkit - use correct case for offline players
+ } finally { this.lookupLock.unlock(); } // Paper - Fix GameProfileCache concurrency
if (optional.isPresent()) {
this.add((GameProfile) optional.get());
flag = false;
@@ -167,6 +181,7 @@ public class GameProfileCache {
}
return optional;
+ } finally { if (stateLocked) { this.stateLock.unlock(); } } // Paper - Fix GameProfileCache concurrency
}
public CompletableFuture<Optional<GameProfile>> getAsync(String username) {
@@ -191,6 +206,7 @@ public class GameProfileCache {
}
public Optional<GameProfile> get(UUID uuid) {
+ try { this.stateLock.lock(); // Paper - Fix GameProfileCache concurrency
GameProfileCache.GameProfileInfo usercache_usercacheentry = (GameProfileCache.GameProfileInfo) this.profilesByUUID.get(uuid);
if (usercache_usercacheentry == null) {
@@ -199,6 +215,7 @@ public class GameProfileCache {
usercache_usercacheentry.setLastAccess(this.getNextOperation());
return Optional.of(usercache_usercacheentry.getProfile());
}
+ } finally { this.stateLock.unlock(); } // Paper - Fix GameProfileCache concurrency
}
public void setExecutor(Executor executor) {
@@ -279,7 +296,7 @@ public class GameProfileCache {
JsonArray jsonarray = new JsonArray();
DateFormat dateformat = GameProfileCache.createDateFormat();
- this.getTopMRUProfiles(org.spigotmc.SpigotConfig.userCacheCap).forEach((usercache_usercacheentry) -> { // Spigot
+ this.listTopMRUProfiles(org.spigotmc.SpigotConfig.userCacheCap).forEach((usercache_usercacheentry) -> { // Spigot // Paper - Fix GameProfileCache concurrency
jsonarray.add(GameProfileCache.writeGameProfile(usercache_usercacheentry, dateformat));
});
String s = this.gson.toJson(jsonarray);
@@ -320,8 +337,19 @@ public class GameProfileCache {
}
private Stream<GameProfileCache.GameProfileInfo> getTopMRUProfiles(int limit) {
- return ImmutableList.copyOf(this.profilesByUUID.values()).stream().sorted(Comparator.comparing(GameProfileCache.GameProfileInfo::getLastAccess).reversed()).limit((long) limit);
+ // Paper start - Fix GameProfileCache concurrency
+ return this.listTopMRUProfiles(limit).stream();
+ }
+
+ private List<GameProfileCache.GameProfileInfo> listTopMRUProfiles(int limit) {
+ try {
+ this.stateLock.lock();
+ return this.profilesByUUID.values().stream().sorted(Comparator.comparing(GameProfileCache.GameProfileInfo::getLastAccess).reversed()).limit(limit).toList();
+ } finally {
+ this.stateLock.unlock();
+ }
}
+ // Paper end - Fix GameProfileCache concurrency
private static JsonElement writeGameProfile(GameProfileCache.GameProfileInfo entry, DateFormat dateFormat) {
JsonObject jsonobject = new JsonObject();