init: add option to read file fully on readahead
Bug: 62413151
Test: boottime, dumpcache
Change-Id: I1a7b69f0619428e4db31c5a7639c5d895c89ecdb
diff --git a/init/README.md b/init/README.md
index b681f21..7df37ff 100644
--- a/init/README.md
+++ b/init/README.md
@@ -453,8 +453,9 @@
`rmdir <path>`
> Calls rmdir(2) on the given path.
-`readahead <file|dir>`
+`readahead <file|dir> [--fully]`
> Calls readahead(2) on the file or files within given directory.
+ Use option --fully to read the full file content.
`setprop <name> <value>`
> Set system property _name_ to _value_. Properties are expanded
diff --git a/init/builtins.cpp b/init/builtins.cpp
index e2e3d93..140ef75 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -56,6 +56,7 @@
#include <selinux/android.h>
#include <selinux/label.h>
#include <selinux/selinux.h>
+#include <system/thread_defs.h>
#include "action.h"
#include "bootchart.h"
@@ -670,6 +671,29 @@
return Success();
}
+static Result<Success> readahead_file(const std::string& filename, bool fully) {
+ android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(filename.c_str(), O_RDONLY)));
+ if (fd == -1) {
+ return ErrnoError() << "Error opening file";
+ }
+ if (posix_fadvise(fd, 0, 0, POSIX_FADV_WILLNEED)) {
+ return ErrnoError() << "Error posix_fadvise file";
+ }
+ if (readahead(fd, 0, std::numeric_limits<size_t>::max())) {
+ return ErrnoError() << "Error readahead file";
+ }
+ if (fully) {
+ char buf[BUFSIZ];
+ ssize_t n;
+ while ((n = TEMP_FAILURE_RETRY(read(fd, &buf[0], sizeof(buf)))) > 0) {
+ }
+ if (n != 0) {
+ return ErrnoError() << "Error reading file";
+ }
+ }
+ return Success();
+}
+
static Result<Success> do_readahead(const std::vector<std::string>& args) {
struct stat sb;
@@ -677,6 +701,10 @@
return ErrnoError() << "Error opening " << args[1];
}
+ bool readfully = false;
+ if (args.size() == 3 && args[2] == "--fully") {
+ readfully = true;
+ }
// We will do readahead in a forked process in order not to block init
// since it may block while it reads the
// filesystem metadata needed to locate the requested blocks. This
@@ -685,15 +713,16 @@
// the requested data has been read.
pid_t pid = fork();
if (pid == 0) {
+ if (setpriority(PRIO_PROCESS, 0, static_cast<int>(ANDROID_PRIORITY_LOWEST)) != 0) {
+ PLOG(WARNING) << "setpriority failed";
+ }
+ if (android_set_ioprio(0, IoSchedClass_IDLE, 7)) {
+ PLOG(WARNING) << "ioprio_get failed";
+ }
android::base::Timer t;
if (S_ISREG(sb.st_mode)) {
- android::base::unique_fd fd(TEMP_FAILURE_RETRY(open(args[1].c_str(), O_RDONLY)));
- if (fd == -1) {
- PLOG(ERROR) << "Error opening file: " << args[1];
- _exit(EXIT_FAILURE);
- }
- if (readahead(fd, 0, std::numeric_limits<size_t>::max())) {
- PLOG(ERROR) << "Error readahead file: " << args[1];
+ if (auto result = readahead_file(args[1], readfully); !result) {
+ LOG(WARNING) << "Unable to readahead '" << args[1] << "': " << result.error();
_exit(EXIT_FAILURE);
}
} else if (S_ISDIR(sb.st_mode)) {
@@ -708,19 +737,15 @@
for (FTSENT* ftsent = fts_read(fts.get()); ftsent != nullptr;
ftsent = fts_read(fts.get())) {
if (ftsent->fts_info & FTS_F) {
- android::base::unique_fd fd(
- TEMP_FAILURE_RETRY(open(ftsent->fts_accpath, O_RDONLY)));
- if (fd == -1) {
- PLOG(ERROR) << "Error opening file: " << args[1];
- continue;
- }
- if (readahead(fd, 0, std::numeric_limits<size_t>::max())) {
- PLOG(ERROR) << "Unable to readahead on file: " << ftsent->fts_accpath;
+ const std::string filename = ftsent->fts_accpath;
+ if (auto result = readahead_file(filename, readfully); !result) {
+ LOG(WARNING)
+ << "Unable to readahead '" << filename << "': " << result.error();
}
}
}
}
- LOG(INFO) << "Readahead " << args[1] << " took " << t;
+ LOG(INFO) << "Readahead " << args[1] << " took " << t << " asynchronously";
_exit(0);
} else if (pid < 0) {
return ErrnoError() << "Fork failed";
@@ -949,7 +974,7 @@
{"mount_all", {1, kMax, do_mount_all}},
{"mount", {3, kMax, do_mount}},
{"umount", {1, 1, do_umount}},
- {"readahead", {1, 1, do_readahead}},
+ {"readahead", {1, 2, do_readahead}},
{"restart", {1, 1, do_restart}},
{"restorecon", {1, kMax, do_restorecon}},
{"restorecon_recursive", {1, kMax, do_restorecon_recursive}},