Create a highmem pool and put metalava into it

Create a highmem pool based on the total RAM and the number of CPUs,
with an override via the NINJA_HIGHMEM_NUM_JOBS variable.  Put
metalava into the highmem pool.

Ninja does not support nested pools, and when goma or RBE is enabled
the maximum ninja parallelism is set very high with local jobs in a
local pool.  When both the local pool and highmem pool are enabled,
the total number of local jobs will be as high as the sum of the sizes
of the two pools.  Keep the highmem pool limited to 1/16th of the
local pool when remote builds are enabled to try to minimize the
effect while still limiting highmem jobs.

Fixes: 142644983
Test: m nothing, examine pools
Test: m USE_GOMA=true nothing, examine pools
Change-Id: Id79f11f44948992960ac34ecf831dacbe21bd332
diff --git a/android/config.go b/android/config.go
index 1cb543d..88bc61a 100644
--- a/android/config.go
+++ b/android/config.go
@@ -827,6 +827,10 @@
 	return Bool(c.productVariables.UseRBE)
 }
 
+func (c *config) UseRemoteBuild() bool {
+	return c.UseGoma() || c.UseRBE()
+}
+
 func (c *config) RunErrorProne() bool {
 	return c.IsEnvTrue("RUN_ERROR_PRONE")
 }
diff --git a/android/defs.go b/android/defs.go
index 4890c66..5c815e6 100644
--- a/android/defs.go
+++ b/android/defs.go
@@ -99,6 +99,9 @@
 
 	// Used only when USE_GOMA=true is set, to restrict non-goma jobs to the local parallelism value
 	localPool = blueprint.NewBuiltinPool("local_pool")
+
+	// Used for processes that need significant RAM to ensure there are not too many running in parallel.
+	highmemPool = blueprint.NewBuiltinPool("highmem_pool")
 )
 
 func init() {
diff --git a/android/module.go b/android/module.go
index 05115d6..dd0cf8c 100644
--- a/android/module.go
+++ b/android/module.go
@@ -1338,7 +1338,7 @@
 func (m *moduleContext) Rule(pctx PackageContext, name string, params blueprint.RuleParams,
 	argNames ...string) blueprint.Rule {
 
-	if (m.config.UseGoma() || m.config.UseRBE()) && params.Pool == nil {
+	if m.config.UseRemoteBuild() && params.Pool == nil {
 		// When USE_GOMA=true or USE_RBE=true are set and the rule is not supported by goma/RBE, restrict
 		// jobs to the local parallelism value
 		params.Pool = localPool
diff --git a/android/package_ctx.go b/android/package_ctx.go
index a228910..6350667 100644
--- a/android/package_ctx.go
+++ b/android/package_ctx.go
@@ -109,7 +109,7 @@
 		if len(ctx.errors) > 0 {
 			return params, ctx.errors[0]
 		}
-		if (ctx.Config().UseGoma() || ctx.Config().UseRBE()) && params.Pool == nil {
+		if ctx.Config().UseRemoteBuild() && params.Pool == nil {
 			// When USE_GOMA=true or USE_RBE=true are set and the rule is not supported by
 			// goma/RBE, restrict jobs to the local parallelism value
 			params.Pool = localPool
diff --git a/android/rule_builder.go b/android/rule_builder.go
index 6f04672..928ba53 100644
--- a/android/rule_builder.go
+++ b/android/rule_builder.go
@@ -33,6 +33,8 @@
 	temporariesSet map[WritablePath]bool
 	restat         bool
 	sbox           bool
+	highmem        bool
+	remoteable     RemoteRuleSupports
 	sboxOutDir     WritablePath
 	missingDeps    []string
 }
@@ -87,6 +89,19 @@
 	return r
 }
 
+// HighMem marks the rule as a high memory rule, which will limit how many run in parallel with other high memory
+// rules.
+func (r *RuleBuilder) HighMem() *RuleBuilder {
+	r.highmem = true
+	return r
+}
+
+// Remoteable marks the rule as supporting remote execution.
+func (r *RuleBuilder) Remoteable(supports RemoteRuleSupports) *RuleBuilder {
+	r.remoteable = supports
+	return r
+}
+
 // Sbox marks the rule as needing to be wrapped by sbox. The WritablePath should point to the output
 // directory that sbox will wipe. It should not be written to by any other rule. sbox will ensure
 // that all outputs have been written, and will discard any output files that were not specified.
@@ -401,6 +416,17 @@
 		rspFileContent = "$in"
 	}
 
+	var pool blueprint.Pool
+	if ctx.Config().UseGoma() && r.remoteable&SUPPORTS_GOMA != 0 {
+		// When USE_GOMA=true is set and the rule is supported by goma, allow jobs to run outside the local pool.
+	} else if ctx.Config().UseRBE() && r.remoteable&SUPPORTS_RBE != 0 {
+		// When USE_GOMA=true is set and the rule is supported by RBE, allow jobs to run outside the local pool.
+	} else if r.highmem {
+		pool = highmemPool
+	} else if ctx.Config().UseRemoteBuild() {
+		pool = localPool
+	}
+
 	ctx.Build(pctx, BuildParams{
 		Rule: ctx.Rule(pctx, name, blueprint.RuleParams{
 			Command:        commandString,
@@ -408,6 +434,7 @@
 			Restat:         r.restat,
 			Rspfile:        rspFile,
 			RspfileContent: rspFileContent,
+			Pool:           pool,
 		}),
 		Inputs:          rspFileInputs,
 		Implicits:       r.Inputs(),
diff --git a/android/singleton.go b/android/singleton.go
index 91268ad..45a9b82 100644
--- a/android/singleton.go
+++ b/android/singleton.go
@@ -128,7 +128,7 @@
 }
 
 func (s *singletonContextAdaptor) Rule(pctx PackageContext, name string, params blueprint.RuleParams, argNames ...string) blueprint.Rule {
-	if (s.Config().UseGoma() || s.Config().UseRBE()) && params.Pool == nil {
+	if s.Config().UseRemoteBuild() && params.Pool == nil {
 		// When USE_GOMA=true or USE_RBE=true are set and the rule is not supported by goma/RBE, restrict
 		// jobs to the local parallelism value
 		params.Pool = localPool
diff --git a/cmd/soong_ui/main.go b/cmd/soong_ui/main.go
index 974c644..db61fba 100644
--- a/cmd/soong_ui/main.go
+++ b/cmd/soong_ui/main.go
@@ -174,6 +174,10 @@
 	stat.AddOutput(status.NewProtoErrorLog(log, filepath.Join(logsDir, c.logsPrefix+"build_error")))
 	stat.AddOutput(status.NewCriticalPath(log))
 
+	buildCtx.Verbosef("Detected %.3v GB total RAM", float32(config.TotalRAM())/(1024*1024*1024))
+	buildCtx.Verbosef("Parallelism (local/remote/highmem): %v/%v/%v",
+		config.Parallel(), config.RemoteParallel(), config.HighmemParallel())
+
 	defer met.Dump(filepath.Join(logsDir, c.logsPrefix+"soong_metrics"))
 
 	if start, ok := os.LookupEnv("TRACE_BEGIN_SOONG"); ok {
diff --git a/java/droiddoc.go b/java/droiddoc.go
index f62f5f9..a10ec81 100644
--- a/java/droiddoc.go
+++ b/java/droiddoc.go
@@ -1456,6 +1456,8 @@
 
 func metalavaCmd(ctx android.ModuleContext, rule *android.RuleBuilder, javaVersion javaVersion, srcs android.Paths,
 	srcJarList android.Path, bootclasspath, classpath classpath, sourcepaths android.Paths) *android.RuleBuilderCommand {
+	// Metalava uses lots of memory, restrict the number of metalava jobs that can run in parallel.
+	rule.HighMem()
 	cmd := rule.Command().BuiltTool(ctx, "metalava").
 		Flag(config.JavacVmFlags).
 		FlagWithArg("-encoding ", "UTF-8").
diff --git a/ui/build/build.go b/ui/build/build.go
index 1c2d864..de36dce 100644
--- a/ui/build/build.go
+++ b/ui/build/build.go
@@ -46,8 +46,11 @@
 
 var combinedBuildNinjaTemplate = template.Must(template.New("combined").Parse(`
 builddir = {{.OutDir}}
-pool local_pool
+{{if .UseRemoteBuild }}pool local_pool
  depth = {{.Parallel}}
+{{end -}}
+pool highmem_pool
+ depth = {{.HighmemParallel}}
 build _kati_always_build_: phony
 {{if .HasKatiSuffix}}subninja {{.KatiBuildNinjaFile}}
 subninja {{.KatiPackageNinjaFile}}
diff --git a/ui/build/config.go b/ui/build/config.go
index c084171..9b19ede 100644
--- a/ui/build/config.go
+++ b/ui/build/config.go
@@ -722,6 +722,33 @@
 	return c.parallel
 }
 
+func (c *configImpl) HighmemParallel() int {
+	if i, ok := c.environ.GetInt("NINJA_HIGHMEM_NUM_JOBS"); ok {
+		return i
+	}
+
+	const minMemPerHighmemProcess = 8 * 1024 * 1024 * 1024
+	parallel := c.Parallel()
+	if c.UseRemoteBuild() {
+		// Ninja doesn't support nested pools, and when remote builds are enabled the total ninja parallelism
+		// is set very high (i.e. 500).  Using a large value here would cause the total number of running jobs
+		// to be the sum of the sizes of the local and highmem pools, which will cause extra CPU contention.
+		// Return 1/16th of the size of the local pool, rounding up.
+		return (parallel + 15) / 16
+	} else if c.totalRAM == 0 {
+		// Couldn't detect the total RAM, don't restrict highmem processes.
+		return parallel
+	} else if c.totalRAM <= 32*1024*1024*1024 {
+		// Less than 32GB of ram, restrict to 2 highmem processes
+		return 2
+	} else if p := int(c.totalRAM / minMemPerHighmemProcess); p < parallel {
+		// If less than 8GB total RAM per process, reduce the number of highmem processes
+		return p
+	}
+	// No restriction on highmem processes
+	return parallel
+}
+
 func (c *configImpl) TotalRAM() uint64 {
 	return c.totalRAM
 }
@@ -782,10 +809,11 @@
 // gomacc) are run in parallel.  Note the parallelism of all other jobs is
 // still limited by Parallel()
 func (c *configImpl) RemoteParallel() int {
-	if v, ok := c.environ.Get("NINJA_REMOTE_NUM_JOBS"); ok {
-		if i, err := strconv.Atoi(v); err == nil {
-			return i
-		}
+	if !c.UseRemoteBuild() {
+		return 0
+	}
+	if i, ok := c.environ.GetInt("NINJA_REMOTE_NUM_JOBS"); ok {
+		return i
 	}
 	return 500
 }
diff --git a/ui/build/config_darwin.go b/ui/build/config_darwin.go
index 480d8d1..fe74e31 100644
--- a/ui/build/config_darwin.go
+++ b/ui/build/config_darwin.go
@@ -22,7 +22,7 @@
 func detectTotalRAM(ctx Context) uint64 {
 	s, err := syscall.Sysctl("hw.memsize")
 	if err != nil {
-		ctx.Printf("Failed to get system memory size: %s")
+		ctx.Printf("Failed to get system memory size: %v", err)
 		return 0
 	}
 
@@ -32,7 +32,7 @@
 	}
 
 	if len(s) != 8 {
-		ctx.Printf("Failed to get system memory size, returned %d bytes, 8", len(s))
+		ctx.Printf("Failed to get system memory size, returned %d bytes, expecting 8 bytes", len(s))
 		return 0
 	}
 
diff --git a/ui/build/config_linux.go b/ui/build/config_linux.go
index 9e1bdc7..162d372 100644
--- a/ui/build/config_linux.go
+++ b/ui/build/config_linux.go
@@ -20,9 +20,8 @@
 	var info syscall.Sysinfo_t
 	err := syscall.Sysinfo(&info)
 	if err != nil {
-		ctx.Printf("Failed to get system memory size: %s")
+		ctx.Printf("Failed to get system memory size: %v", err)
 		return 0
 	}
-	memBytes := uint64(info.Totalram) * uint64(info.Unit)
-	return memBytes
+	return uint64(info.Totalram) * uint64(info.Unit)
 }
diff --git a/ui/build/environment.go b/ui/build/environment.go
index d8ff7f2..9bca7c0 100644
--- a/ui/build/environment.go
+++ b/ui/build/environment.go
@@ -19,6 +19,7 @@
 	"fmt"
 	"io"
 	"os"
+	"strconv"
 	"strings"
 )
 
@@ -44,6 +45,17 @@
 	return "", false
 }
 
+// Get returns the int value associated with the key, and whether it exists
+// and is a valid int.
+func (e *Environment) GetInt(key string) (int, bool) {
+	if v, ok := e.Get(key); ok {
+		if i, err := strconv.Atoi(v); err == nil {
+			return i, true
+		}
+	}
+	return 0, false
+}
+
 // Set sets the value associated with the key, overwriting the current value
 // if it exists.
 func (e *Environment) Set(key, value string) {