From 22de216799d97c1f75972717b70355a3017635d9 Mon Sep 17 00:00:00 2001
From: Dan Willemsen <dwillemsen@google.com>
Date: Mon, 11 Dec 2017 14:35:23 -0800
Subject: [PATCH] Increase per-process file limits for multiproduct_kati

On large branches (250+ configurations), the open file count can go
over the default 1024 soft limit on Ubuntu. Many systems have increased
that default, but for the ones that haven't, at least opt into the
hard limit until this can be refactored to use fewer open files.

Bug: 70370883
Test: prlimit -n256:4096 build/soong/build_test.bash -only-config
Test: ulimit -Sn 256; build/soong/build_test.bash -only-config (darwin)
Change-Id: I7a952ffc89a0149ab65b04db1523d348daa6ab3e
---
 cmd/multiproduct_kati/main.go | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/cmd/multiproduct_kati/main.go b/cmd/multiproduct_kati/main.go
index 2fee1f78c..06c562640 100644
--- a/cmd/multiproduct_kati/main.go
+++ b/cmd/multiproduct_kati/main.go
@@ -24,6 +24,7 @@ import (
 	"runtime"
 	"strings"
 	"sync"
+	"syscall"
 	"time"
 
 	"android/soong/ui/build"
@@ -159,6 +160,30 @@ func (s *Status) Finished() int {
 	return s.failed
 }
 
+// TODO(b/70370883): This tool uses a lot of open files -- over the default
+// soft limit of 1024 on some systems. So bump up to the hard limit until I fix
+// the algorithm.
+func setMaxFiles(log logger.Logger) {
+	var limits syscall.Rlimit
+
+	err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limits)
+	if err != nil {
+		log.Println("Failed to get file limit:", err)
+		return
+	}
+
+	log.Verbosef("Current file limits: %d soft, %d hard", limits.Cur, limits.Max)
+	if limits.Cur == limits.Max {
+		return
+	}
+
+	limits.Cur = limits.Max
+	err = syscall.Setrlimit(syscall.RLIMIT_NOFILE, &limits)
+	if err != nil {
+		log.Println("Failed to increase file limit:", err)
+	}
+}
+
 func inList(str string, list []string) bool {
 	for _, other := range list {
 		if str == other {
@@ -228,6 +253,8 @@ func main() {
 		trace.SetOutput(filepath.Join(config.OutDir(), "build.trace"))
 	}
 
+	setMaxFiles(log)
+
 	vars, err := build.DumpMakeVars(buildCtx, config, nil, []string{"all_named_products"})
 	if err != nil {
 		log.Fatal(err)