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dfs: Fix caching of index, bitmap index, reverse index 

When 07f98a8b71 ("Derive DfsStreamKey from DfsPackDescription")
stopped caching DfsPackFile in the DfsBlockCache, the DfsPackFile began
to always load the idx, bitmap, or compute reverse index, as the cache
handles were no longer populated by prior requests.

Rework caching to lookup the objects from the DfsBlockCache if the
local DfsPackFile handle is invalid.  This allows the DfsPackFile to
be more of a flyweight instance across requests.

Change-Id: Ic7b42ce2d90692cccea36deb30c2c76ccc81638b
This commit is contained in:
Shawn Pearce 2017-07-18 21:58:30 -07:00
parent b1bdeeb0ee
commit da7671fcd5
2 changed files with 59 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsBlockCache.java
View File

@ -390,6 +390,10 @@ void put(DfsBlock v) {
put(v.stream, v.start, v.size(), v);
}
<T> Ref<T> putRef(DfsStreamKey key, long size, T v) {
return put(key, 0, (int) Math.min(size, Integer.MAX_VALUE), v);
}
<T> Ref<T> put(DfsStreamKey key, long pos, int size, T v) {
int slot = slot(key, pos);
HashEntry e1 = table.get(slot);
@ -444,6 +448,15 @@ private <T> T scan(HashEntry n, DfsStreamKey key, long position) {
return r != null ? r.get() : null;
}
<T> Ref<T> getRef(DfsStreamKey key) {
Ref<T> r = scanRef(table.get(slot(key, 0)), key, 0);
if (r != null)
statHit.incrementAndGet();
else
statMiss.incrementAndGet();
return r;
}
@SuppressWarnings("unchecked")
private <T> Ref<T> scanRef(HashEntry n, DfsStreamKey key, long position) {
for (; n != null; n = n.next) {

76
org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/dfs/DfsPackFile.java
View File

@ -144,8 +144,8 @@ public boolean isIndexLoaded() {
void setPackIndex(PackIndex idx) {
long objCnt = idx.getObjectCount();
int recSize = Constants.OBJECT_ID_LENGTH + 8;
int sz = (int) Math.min(objCnt * recSize, Integer.MAX_VALUE);
index = cache.put(desc.getStreamKey(INDEX), 0, sz, idx);
long sz = objCnt * recSize;
index = cache.putRef(desc.getStreamKey(INDEX), sz, idx);
}
/**
@ -184,6 +184,16 @@ private PackIndex idx(DfsReader ctx) throws IOException {
return idx;
}
DfsStreamKey idxKey = desc.getStreamKey(INDEX);
idxref = cache.getRef(idxKey);
if (idxref != null) {
PackIndex idx = idxref.get();
if (idx != null) {
index = idxref;
return idx;
}
}
PackIndex idx;
try {
ctx.stats.readIdx++;
@ -205,18 +215,14 @@ else if (bs <= 0)
}
} catch (EOFException e) {
invalid = true;
IOException e2 = new IOException(MessageFormat.format(
throw new IOException(MessageFormat.format(
DfsText.get().shortReadOfIndex,
desc.getFileName(INDEX)));
e2.initCause(e);
throw e2;
desc.getFileName(INDEX)), e);
} catch (IOException e) {
invalid = true;
IOException e2 = new IOException(MessageFormat.format(
throw new IOException(MessageFormat.format(
DfsText.get().cannotReadIndex,
desc.getFileName(INDEX)));
e2.initCause(e);
throw e2;
desc.getFileName(INDEX)), e);
}
setPackIndex(idx);
@ -229,8 +235,9 @@ final boolean isGarbage() {
}
PackBitmapIndex getBitmapIndex(DfsReader ctx) throws IOException {
if (invalid || isGarbage())
if (invalid || isGarbage() || !desc.hasFileExt(BITMAP_INDEX))
return null;
DfsBlockCache.Ref<PackBitmapIndex> idxref = bitmapIndex;
if (idxref != null) {
PackBitmapIndex idx = idxref.get();
@ -238,9 +245,6 @@ PackBitmapIndex getBitmapIndex(DfsReader ctx) throws IOException {
return idx;
}
if (!desc.hasFileExt(BITMAP_INDEX))
return null;
synchronized (initLock) {
idxref = bitmapIndex;
if (idxref != null) {
@ -249,6 +253,16 @@ PackBitmapIndex getBitmapIndex(DfsReader ctx) throws IOException {
return idx;
}
DfsStreamKey bitmapKey = desc.getStreamKey(BITMAP_INDEX);
idxref = cache.getRef(bitmapKey);
if (idxref != null) {
PackBitmapIndex idx = idxref.get();
if (idx != null) {
bitmapIndex = idxref;
return idx;
}
}
long size;
PackBitmapIndex idx;
try {
@ -273,22 +287,16 @@ else if (bs <= 0)
ctx.stats.readIdxMicros += elapsedMicros(start);
}
} catch (EOFException e) {
IOException e2 = new IOException(MessageFormat.format(
throw new IOException(MessageFormat.format(
DfsText.get().shortReadOfIndex,
desc.getFileName(BITMAP_INDEX)));
e2.initCause(e);
throw e2;
desc.getFileName(BITMAP_INDEX)), e);
} catch (IOException e) {
IOException e2 = new IOException(MessageFormat.format(
throw new IOException(MessageFormat.format(
DfsText.get().cannotReadIndex,
desc.getFileName(BITMAP_INDEX)));
e2.initCause(e);
throw e2;
desc.getFileName(BITMAP_INDEX)), e);
}
bitmapIndex = cache.put(
desc.getStreamKey(BITMAP_INDEX),
0, (int) Math.min(size, Integer.MAX_VALUE), idx);
bitmapIndex = cache.putRef(bitmapKey, size, idx);
return idx;
}
}
@ -309,13 +317,21 @@ PackReverseIndex getReverseIdx(DfsReader ctx) throws IOException {
return revidx;
}
DfsStreamKey revKey =
new DfsStreamKey.ForReverseIndex(desc.getStreamKey(INDEX));
revref = cache.getRef(revKey);
if (revref != null) {
PackReverseIndex idx = revref.get();
if (idx != null) {
reverseIndex = revref;
return idx;
}
}
PackIndex idx = idx(ctx);
PackReverseIndex revidx = new PackReverseIndex(idx);
int sz = (int) Math.min(
idx.getObjectCount() * 8, Integer.MAX_VALUE);
reverseIndex = cache.put(
new DfsStreamKey.ForReverseIndex(desc.getStreamKey(INDEX)),
0, sz, revidx);
long cnt = idx.getObjectCount();
reverseIndex = cache.putRef(revKey, cnt * 8, revidx);
return revidx;
}
}