From df6f2d68607accc290b10b68c83abb26f8c9c8ab Mon Sep 17 00:00:00 2001 From: Philipp Marx Date: Sat, 12 Nov 2016 11:11:19 +0100 Subject: [PATCH] Reduce synchronized scope around ConcurrentHashMap Change-Id: I982a78070efb6bc2d3395330456d62e0d5ce6da7 Signed-off-by: Philipp Marx --- .../internal/storage/dfs/DfsBlockCache.java | 30 +++++++++---------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsBlockCache.java b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsBlockCache.java index 05627ed86b..f7decf1324 100644 --- a/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsBlockCache.java +++ b/org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsBlockCache.java @@ -263,20 +263,22 @@ public final class DfsBlockCache { // TODO This table grows without bound. It needs to clean up // entries that aren't in cache anymore, and aren't being used // by a live DfsObjDatabase reference. - synchronized (packCache) { - DfsPackFile pack = packCache.get(dsc); - if (pack != null && pack.invalid()) { - packCache.remove(dsc); - pack = null; - } - if (pack == null) { - if (key == null) - key = new DfsPackKey(); - pack = new DfsPackFile(this, dsc, key); - packCache.put(dsc, pack); - } + + DfsPackFile pack = packCache.get(dsc); + if (pack != null && !pack.invalid()) { return pack; } + + // 'pack' either didn't exist or was invalid. Compute a new + // entry atomically (guaranteed by ConcurrentHashMap). + return packCache.compute(dsc, (k, v) -> { + if (v != null && !v.invalid()) { // valid value added by + return v; // another thread + } else { + return new DfsPackFile( + this, dsc, key != null ? key : new DfsPackKey()); + } + }); } private int hash(int packHash, long off) { @@ -504,9 +506,7 @@ public final class DfsBlockCache { } void remove(DfsPackFile pack) { - synchronized (packCache) { - packCache.remove(pack.getPackDescription()); - } + packCache.remove(pack.getPackDescription()); } private int slot(DfsPackKey pack, long position) { -- 2.39.5