WIP: split processmanager/ebpf in two packages: interface and implementation

processmanager/ebpf/handler.go

@@ -0,0 +1,108 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package ebpf // import "go.opentelemetry.io/ebpf-profiler/processmanager/ebpf"
+
+/*
+#include <stdint.h>
+#include "../../support/ebpf/types.h"
+*/
+import "C"
+
+import (
+	"fmt"
+
+	"go.opentelemetry.io/ebpf-profiler/host"
+	"go.opentelemetry.io/ebpf-profiler/interpreter"
+	"go.opentelemetry.io/ebpf-profiler/libpf"
+	"go.opentelemetry.io/ebpf-profiler/lpm"
+	"go.opentelemetry.io/ebpf-profiler/metrics"
+	"go.opentelemetry.io/ebpf-profiler/nativeunwind/stackdeltatypes"
+	"go.opentelemetry.io/ebpf-profiler/util"
+)
+
+// EbpfHandler provides the functionality to interact with eBPF maps.
+type EbpfHandler interface {
+	// Embed interpreter.EbpfHandler as subset of this interface.
+	interpreter.EbpfHandler
+
+	// RemoveReportedPID removes a PID from the reported_pids eBPF map.
+	RemoveReportedPID(pid libpf.PID)
+
+	// UpdateUnwindInfo writes UnwindInfo to given unwind info array index
+	UpdateUnwindInfo(index uint16, info stackdeltatypes.UnwindInfo) error
+
+	// UpdateExeIDToStackDeltas defines a function that updates the eBPF map exe_id_to_stack_deltas
+	// for host.FileID with the elements of StackDeltaEBPF. It returns the mapID used.
+	UpdateExeIDToStackDeltas(fileID host.FileID, deltas []StackDeltaEBPF) (uint16, error)
+
+	// DeleteExeIDToStackDeltas defines a function that removes the entries from the outer eBPF
+	// map exe_id_to_stack_deltas and its associated inner map entries.
+	DeleteExeIDToStackDeltas(fileID host.FileID, mapID uint16) error
+
+	// UpdateStackDeltaPages defines a function that updates the mapping in a eBPF map from
+	// a FileID and page to its stack delta lookup information.
+	UpdateStackDeltaPages(fileID host.FileID, numDeltasPerPage []uint16,
+		mapID uint16, firstPageAddr uint64) error
+
+	// DeleteStackDeltaPage defines a function that removes the element specified by fileID and page
+	// from the eBPF map.
+	DeleteStackDeltaPage(fileID host.FileID, page uint64) error
+
+	// UpdatePidPageMappingInfo defines a function that updates the eBPF map
+	// pid_page_to_mapping_info with the given pidAndPage and fileIDAndOffset encoded values
+	// as key/value pair.
+	UpdatePidPageMappingInfo(pid libpf.PID, prefix lpm.Prefix, fileID, bias uint64) error
+
+	// DeletePidPageMappingInfo removes the elements specified by prefixes from eBPF map
+	// pid_page_to_mapping_info and returns the number of elements removed.
+	DeletePidPageMappingInfo(pid libpf.PID, prefixes []lpm.Prefix) (int, error)
+
+	// CollectMetrics returns gathered errors for changes to eBPF maps.
+	CollectMetrics() []metrics.Metric
+
+	// SupportsGenericBatchOperations returns true if the kernel supports eBPF batch operations
+	// on hash and array maps.
+	SupportsGenericBatchOperations() bool
+
+	// SupportsLPMTrieBatchOperations returns true if the kernel supports eBPF batch operations
+	// on LPM trie maps.
+	SupportsLPMTrieBatchOperations() bool
+}
+
+// StackDeltaEBPF represents stack deltas preprocessed by the ProcessManager which are
+// then loaded to the eBPF map. This is Go equivalent of 'struct StackDelta' in eBPF types.h.
+// See the eBPF header file for details.
+type StackDeltaEBPF struct {
+	AddressLow uint16
+	UnwindInfo uint16
+}
+
+func InterpreterOffsetKeyValue(ebpfProgIndex uint16, fileID host.FileID,
+	offsetRanges []util.Range) (key uint64, value C.OffsetRange, err error) {
+	rLen := len(offsetRanges)
+	if rLen < 1 || rLen > 2 {
+		return 0, C.OffsetRange{}, fmt.Errorf("invalid ranges %v", offsetRanges)
+	}
+	//  The keys of this map are executable-id-and-offset-into-text entries, and
+	//  the offset_range associated with them gives the precise area in that page
+	//  where the main interpreter loop is located. This is required to unwind
+	//  nicely from native code into interpreted code.
+	key = uint64(fileID)
+	first := offsetRanges[0]
+	value = C.OffsetRange{
+		lower_offset1: C.u64(first.Start),
+		upper_offset1: C.u64(first.End),
+		program_index: C.u16(ebpfProgIndex),
+	}
+	if len(offsetRanges) == 2 {
+		// Fields {lower,upper}_offset2 may be used to specify an optional second range
+		// of an interpreter function. This may be useful if the interpreter function
+		// consists of two non-contiguous memory ranges, which may happen due to Hot/Cold
+		// split compiler optimization
+		second := offsetRanges[1]
+		value.lower_offset2 = C.u64(second.Start)
+		value.upper_offset2 = C.u64(second.End)
+	}
+	return key, value, nil
+}

processmanager/ebpf/asyncupdate.go → processmanager/ebpf/impl/asyncupdate.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package ebpf // import "go.opentelemetry.io/ebpf-profiler/processmanager/ebpf"
+package impl // import "go.opentelemetry.io/ebpf-profiler/processmanager/ebpf"
 
 import (
 	"context"

processmanager/ebpf/asyncupdate_integration_test.go → processmanager/ebpf/impl/asyncupdate_integration_test.go

@@ -3,7 +3,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package ebpf
+package impl
 
 import (
 	"context"

processmanager/ebpf/ebpf.go → processmanager/ebpf/impl/ebpf.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package ebpf // import "go.opentelemetry.io/ebpf-profiler/processmanager/ebpf"
+package impl // import "go.opentelemetry.io/ebpf-profiler/processmanager/ebpf"
 
 import (
 	"context"
@@ -15,11 +15,11 @@
 	"github.com/cilium/ebpf/features"
 	log "github.com/sirupsen/logrus"
 	"go.opentelemetry.io/ebpf-profiler/host"
-	"go.opentelemetry.io/ebpf-profiler/interpreter"
 	"go.opentelemetry.io/ebpf-profiler/libpf"
 	"go.opentelemetry.io/ebpf-profiler/lpm"
 	"go.opentelemetry.io/ebpf-profiler/metrics"
 	sdtypes "go.opentelemetry.io/ebpf-profiler/nativeunwind/stackdeltatypes"
+	"go.opentelemetry.io/ebpf-profiler/processmanager/ebpf"
 	"go.opentelemetry.io/ebpf-profiler/rlimit"
 	"go.opentelemetry.io/ebpf-profiler/support"
 	"go.opentelemetry.io/ebpf-profiler/util"
@@ -28,7 +28,7 @@
 
 /*
 #include <stdint.h>
-#include "../../support/ebpf/types.h"
+#include "../../../support/ebpf/types.h"
 */
 import "C"
 
@@ -40,55 +40,6 @@
 	updatePoolQueueCap = 8
 )
 
-// EbpfHandler provides the functionality to interact with eBPF maps.
-type EbpfHandler interface {
-	// Embed interpreter.EbpfHandler as subset of this interface.
-	interpreter.EbpfHandler
-
-	// RemoveReportedPID removes a PID from the reported_pids eBPF map.
-	RemoveReportedPID(pid libpf.PID)
-
-	// UpdateUnwindInfo writes UnwindInfo to given unwind info array index
-	UpdateUnwindInfo(index uint16, info sdtypes.UnwindInfo) error
-
-	// UpdateExeIDToStackDeltas defines a function that updates the eBPF map exe_id_to_stack_deltas
-	// for host.FileID with the elements of StackDeltaEBPF. It returns the mapID used.
-	UpdateExeIDToStackDeltas(fileID host.FileID, deltas []StackDeltaEBPF) (uint16, error)
-
-	// DeleteExeIDToStackDeltas defines a function that removes the entries from the outer eBPF
-	// map exe_id_to_stack_deltas and its associated inner map entries.
-	DeleteExeIDToStackDeltas(fileID host.FileID, mapID uint16) error
-
-	// UpdateStackDeltaPages defines a function that updates the mapping in a eBPF map from
-	// a FileID and page to its stack delta lookup information.
-	UpdateStackDeltaPages(fileID host.FileID, numDeltasPerPage []uint16,
-		mapID uint16, firstPageAddr uint64) error
-
-	// DeleteStackDeltaPage defines a function that removes the element specified by fileID and page
-	// from the eBPF map.
-	DeleteStackDeltaPage(fileID host.FileID, page uint64) error
-
-	// UpdatePidPageMappingInfo defines a function that updates the eBPF map
-	// pid_page_to_mapping_info with the given pidAndPage and fileIDAndOffset encoded values
-	// as key/value pair.
-	UpdatePidPageMappingInfo(pid libpf.PID, prefix lpm.Prefix, fileID, bias uint64) error
-
-	// DeletePidPageMappingInfo removes the elements specified by prefixes from eBPF map
-	// pid_page_to_mapping_info and returns the number of elements removed.
-	DeletePidPageMappingInfo(pid libpf.PID, prefixes []lpm.Prefix) (int, error)
-
-	// CollectMetrics returns gathered errors for changes to eBPF maps.
-	CollectMetrics() []metrics.Metric
-
-	// SupportsGenericBatchOperations returns true if the kernel supports eBPF batch operations
-	// on hash and array maps.
-	SupportsGenericBatchOperations() bool
-
-	// SupportsLPMTrieBatchOperations returns true if the kernel supports eBPF batch operations
-	// on LPM trie maps.
-	SupportsLPMTrieBatchOperations() bool
-}
-
 type ebpfMapsImpl struct {
 	// Interpreter related eBPF maps
 	interpreterOffsets *cebpf.Map
@@ -138,14 +89,14 @@
 }
 
 // Compile time check to make sure ebpfMapsImpl satisfies the interface .
-var _ EbpfHandler = &ebpfMapsImpl{}
+var _ ebpf.EbpfHandler = &ebpfMapsImpl{}
 
 // LoadMaps checks if the needed maps for the process manager are available
 // and loads their references into a package-internal structure.
 //
 // It further spawns background workers for deferred map updates; the given
 // context can be used to terminate them on shutdown.
-func LoadMaps(ctx context.Context, maps map[string]*cebpf.Map) (EbpfHandler, error) {
+func LoadMaps(ctx context.Context, maps map[string]*cebpf.Map) (ebpf.EbpfHandler, error) {
 	impl := &ebpfMapsImpl{}
 	impl.errCounter = make(map[metrics.MetricID]int64)
 
@@ -256,7 +207,7 @@
 // UpdateInterpreterOffsets adds the given moduleRanges to the eBPF map interpreterOffsets.
 func (impl *ebpfMapsImpl) UpdateInterpreterOffsets(ebpfProgIndex uint16, fileID host.FileID,
 	offsetRanges []util.Range) error {
-	key, value, err := InterpreterOffsetKeyValue(ebpfProgIndex, fileID, offsetRanges)
+	key, value, err := ebpf.InterpreterOffsetKeyValue(ebpfProgIndex, fileID, offsetRanges)
 	if err != nil {
 		return err
 	}
@@ -268,35 +219,6 @@
 	return nil
 }
 
-func InterpreterOffsetKeyValue(ebpfProgIndex uint16, fileID host.FileID,
-	offsetRanges []util.Range) (key uint64, value C.OffsetRange, err error) {
-	rLen := len(offsetRanges)
-	if rLen < 1 || rLen > 2 {
-		return 0, C.OffsetRange{}, fmt.Errorf("invalid ranges %v", offsetRanges)
-	}
-	//  The keys of this map are executable-id-and-offset-into-text entries, and
-	//  the offset_range associated with them gives the precise area in that page
-	//  where the main interpreter loop is located. This is required to unwind
-	//  nicely from native code into interpreted code.
-	key = uint64(fileID)
-	first := offsetRanges[0]
-	value = C.OffsetRange{
-		lower_offset1: C.u64(first.Start),
-		upper_offset1: C.u64(first.End),
-		program_index: C.u16(ebpfProgIndex),
-	}
-	if len(offsetRanges) == 2 {
-		// Fields {lower,upper}_offset2 may be used to specify an optional second range
-		// of an interpreter function. This may be useful if the interpreter function
-		// consists of two non-contiguous memory ranges, which may happen due to Hot/Cold
-		// split compiler optimization
-		second := offsetRanges[1]
-		value.lower_offset2 = C.u64(second.Start)
-		value.upper_offset2 = C.u64(second.End)
-	}
-	return key, value, nil
-}
-
 // getInterpreterTypeMap returns the eBPF map for the given typ
 // or an error if typ is not supported.
 func (impl *ebpfMapsImpl) getInterpreterTypeMap(typ libpf.InterpreterType) (*cebpf.Map, error) {
@@ -592,7 +514,7 @@
 
 // UpdateExeIDToStackDeltas creates a nested map for fileID in the eBPF map exeIDTostack_deltas
 // and inserts the elements of the deltas array in this nested map. Returns mapID or error.
-func (impl *ebpfMapsImpl) UpdateExeIDToStackDeltas(fileID host.FileID, deltas []StackDeltaEBPF) (
+func (impl *ebpfMapsImpl) UpdateExeIDToStackDeltas(fileID host.FileID, deltas []ebpf.StackDeltaEBPF) (
 	uint16, error) {
 	numDeltas := len(deltas)
 	mapID, err := getMapID(uint32(numDeltas))

processmanager/ebpf/ebpf_integration_test.go → processmanager/ebpf/impl/ebpf_integration_test.go

@@ -3,7 +3,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package ebpf
+package impl
 
 import (
 	"testing"

processmanager/ebpf/ebpf_test.go → processmanager/ebpf/impl/ebpf_test.go

@@ -1,7 +1,7 @@
 // Copyright The OpenTelemetry Authors
 // SPDX-License-Identifier: Apache-2.0
 
-package ebpf
+package impl
 
 import (
 	"fmt"

tracer/tracer.go

@@ -31,7 +31,7 @@ import (
 	"go.opentelemetry.io/ebpf-profiler/nativeunwind/elfunwindinfo"
 	"go.opentelemetry.io/ebpf-profiler/periodiccaller"
 	pm "go.opentelemetry.io/ebpf-profiler/processmanager"
-	pmebpf "go.opentelemetry.io/ebpf-profiler/processmanager/ebpf"
+	pmebpf "go.opentelemetry.io/ebpf-profiler/processmanager/ebpf/impl"
 	"go.opentelemetry.io/ebpf-profiler/reporter"
 	"go.opentelemetry.io/ebpf-profiler/rlimit"
 	"go.opentelemetry.io/ebpf-profiler/support"