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core/rawdb, eth/downloader: align 64bit atomic fields #19591

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Merged
merged 1 commit into from
May 16, 2019
+17 −5
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core/rawdb, eth/downloader: align 64bit atomic fields #19591

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6 changes: 5 additions & 1 deletion core/rawdb/freezer.go
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Original file line number Diff line number Diff line change
Expand Up @@ -66,8 +66,12 @@ const (
// reserving it for go-ethereum. This would also reduce the memory requirements
// of Geth, and thus also GC overhead.
type freezer struct {
// WARNING: The `frozen` field is accessed atomically. On 32 bit platforms, only
// 64-bit aligned fields can be atomic. The struct is guaranteed to be so aligned,
// so take advantage of that (https://golang.org/pkg/sync/atomic/#pkg-note-BUG).
frozen uint64 // Number of blocks already frozen

tables map[string]*freezerTable // Data tables for storing everything
frozen uint64 // Number of blocks already frozen
instanceLock fileutil.Releaser // File-system lock to prevent double opens
}

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6 changes: 5 additions & 1 deletion core/rawdb/freezer_table.go
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Expand Up @@ -73,6 +73,11 @@ func (i *indexEntry) marshallBinary() []byte {
// It consists of a data file (snappy encoded arbitrary data blobs) and an indexEntry
// file (uncompressed 64 bit indices into the data file).
type freezerTable struct {
// WARNING: The `items` field is accessed atomically. On 32 bit platforms, only
// 64-bit aligned fields can be atomic. The struct is guaranteed to be so aligned,
// so take advantage of that (https://golang.org/pkg/sync/atomic/#pkg-note-BUG).
items uint64 // Number of items stored in the table (including items removed from tail)

noCompression bool // if true, disables snappy compression. Note: does not work retroactively
maxFileSize uint32 // Max file size for data-files
name string
Expand All @@ -86,7 +91,6 @@ type freezerTable struct {

// In the case that old items are deleted (from the tail), we use itemOffset
// to count how many historic items have gone missing.
items uint64 // Number of items stored in the table (including items removed from tail)
itemOffset uint32 // Offset (number of discarded items)

headBytes uint32 // Number of bytes written to the head file
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10 changes: 7 additions & 3 deletions eth/downloader/downloader.go
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Expand Up @@ -98,6 +98,13 @@ var (
)

type Downloader struct {
// WARNING: The `rttEstimate` and `rttConfidence` fields are accessed atomically.
// On 32 bit platforms, only 64-bit aligned fields can be atomic. The struct is
// guaranteed to be so aligned, so take advantage of that. For more information,
// see https://golang.org/pkg/sync/atomic/#pkg-note-BUG.
rttEstimate uint64 // Round trip time to target for download requests
rttConfidence uint64 // Confidence in the estimated RTT (unit: millionths to allow atomic ops)

mode SyncMode // Synchronisation mode defining the strategy used (per sync cycle)
mux *event.TypeMux // Event multiplexer to announce sync operation events

Expand All @@ -109,9 +116,6 @@ type Downloader struct {
stateDB ethdb.Database // Database to state sync into (and deduplicate via)
stateBloom *trie.SyncBloom // Bloom filter for fast trie node existence checks

rttEstimate uint64 // Round trip time to target for download requests
rttConfidence uint64 // Confidence in the estimated RTT (unit: millionths to allow atomic ops)

// Statistics
syncStatsChainOrigin uint64 // Origin block number where syncing started at
syncStatsChainHeight uint64 // Highest block number known when syncing started
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