Libguestfs - Mar 2016 - Re: [PATCH supermin 0/5] Make supermin mini-initrd quieter and faster.

Various patches to make supermin quieter.  By outputting fewer
messages on the fast path, we use the slow emulated UART less, and
this improves boot times.

Also remove some kernel modules that we cannot or should not be using,
which also improves boot times.

Rich.

---
 init/init.c | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/init/init.c b/init/init.c
index 80b2232..3014de2 100644
--- a/init/init.c
+++ b/init/init.c
@@ -71,10 +71,10 @@ static const char *moderror(int err)
   }
 }
 
-/* Leave this enabled for now.  When we get more confident in the boot
- * process we can turn this off or make it configurable.
+/* If "quiet" is found on the command line, set this which suppresses
+ * ordinary debug messages.
  */
-#define verbose 1
+static int quiet = 0;
 
 static void mount_proc (void);
 static void print_uptime (void);
@@ -90,7 +90,6 @@ main ()
 {
   mount_proc ();
 
-  print_uptime ();
   fprintf (stderr, "supermin: ext2 mini initrd starting up: "
            PACKAGE_VERSION
 #if defined(__dietlibc__)
@@ -105,6 +104,12 @@ main ()
            "\n");
 
   read_cmdline ();
+  quiet = strstr (cmdline, "quiet") != NULL;
+
+  if (!quiet) {
+    fprintf (stderr, "supermin: cmdline: %s\n", cmdline);
+    print_uptime ();
+  }
 
   /* Create some fixed directories. */
   mkdir ("/dev", 0755);
@@ -112,7 +117,7 @@ main ()
   mkdir ("/sys", 0755);
 
   /* Mount /sys. */
-  if (verbose)
+  if (!quiet)
     fprintf (stderr, "supermin: mounting /sys\n");
   if (mount ("sysfs", "/sys", "sysfs", 0,
"") == -1) {
     perror ("mount: /sys");
@@ -208,7 +213,7 @@ main ()
   exit (EXIT_FAILURE);
 
  found:
-  if (verbose)
+  if (!quiet)
     fprintf (stderr, "supermin: picked %s as root device\n", path);
 
   fgets (line, sizeof line, fp);
@@ -229,7 +234,7 @@ main ()
     perror ("ioctl: TIOCSCTTY");
 #endif
 
-  if (verbose)
+  if (!quiet)
     fprintf (stderr, "supermin: creating /dev/root as block special
%d:%d\n",
              major, minor);
 
@@ -239,7 +244,7 @@ main ()
   }
 
   /* Mount new root and chroot to it. */
-  if (verbose)
+  if (!quiet)
     fprintf (stderr, "supermin: mounting new root on /root\n");
   if (mount ("/dev/root", "/root", "ext2",
MS_NOATIME, "") == -1) {
     perror ("mount: /root");
@@ -250,7 +255,7 @@ main ()
    * Documentation/filesystems/ramfs-rootfs-initramfs.txt
    * We could remove the old initramfs files, but let's not bother.
    */
-  if (verbose)
+  if (!quiet)
     fprintf (stderr, "supermin: chroot\n");
 
   if (chroot ("/root") == -1) {
@@ -282,7 +287,7 @@ insmod (const char *filename)
 {
   size_t size;
 
-  if (verbose)
+  if (!quiet)
     fprintf (stderr, "supermin: internal insmod %s\n", filename);
 
   int fd = open (filename, O_RDONLY);
@@ -323,7 +328,7 @@ mount_proc (void)
   if (access ("/proc/uptime", R_OK) == -1) {
     mkdir ("/proc", 0755);
 
-    if (verbose)
+    if (!quiet)
       fprintf (stderr, "supermin: mounting /proc\n");
 
     if (mount ("proc", "/proc", "proc", 0,
"") == -1) {
@@ -370,8 +375,6 @@ read_cmdline (void)
   len = strlen (cmdline);
   if (len >= 1 && cmdline[len-1] == '\n')
     cmdline[len-1] = '\0';
-
-  fprintf (stderr, "supermin: cmdline: %s\n", cmdline);
 }
 
 /* Display a directory on stderr.  This is used for debugging only. */
-- 
2.5.0

In all modern kernels IDE support is provided by libata, not the
ancient ide*.ko module.

The other disadvantage of this wildcard was that it picked up various
unrelated modules, eg. ideapad_slidebar.ko (plus dependencies).
---
 src/ext2_initrd.ml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/ext2_initrd.ml b/src/ext2_initrd.ml
index 09536d3..50ac924 100644
--- a/src/ext2_initrd.ml
+++ b/src/ext2_initrd.ml
@@ -38,7 +38,6 @@ let kmods = [
   "ext2.ko*";
   "ext4.ko*";    (* CONFIG_EXT4_USE_FOR_EXT23=y option might be set
*)
   "virtio*.ko*";
-  "ide*.ko*";
   "libata*.ko*";
   "piix*.ko*";
   "scsi_transport_spi.ko*";
-- 
2.5.0

The megaraid driver was added to test an old bug.  Remove it since
copying this driver to the mini-initrd and loading it each time is not
free.

This reverts commit 9da479658818738b2a2a68456e867cdb609472c8.
---
 src/ext2_initrd.ml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/ext2_initrd.ml b/src/ext2_initrd.ml
index 50ac924..f222bb8 100644
--- a/src/ext2_initrd.ml
+++ b/src/ext2_initrd.ml
@@ -50,7 +50,6 @@ let kmods = [
   "crc*.ko*";
   "libcrc*.ko*";
   "ibmvscsic.ko*";
-  "megaraid*.ko*";
 ]
 
 let rec build_initrd debug tmpdir modpath initrd -- 
2.5.0

This module is described as "Filesystem Meta Information Block Cache
(mbcache).  The mbcache caches blocks of block devices that need to be
located by their device/block number, as well as by other criteria
(such as the block's contents)."

It is compiled into the kernel in Fedora, and if it is required on
other distros then it should be pulled in by module dependencies.
---
 src/ext2_initrd.ml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/ext2_initrd.ml b/src/ext2_initrd.ml
index f222bb8..730f806 100644
--- a/src/ext2_initrd.ml
+++ b/src/ext2_initrd.ml
@@ -46,7 +46,6 @@ let kmods = [
   "sym53c8xx.ko*";
   "ata_piix.ko*";
   "sr_mod.ko*";
-  "mbcache.ko*";
   "crc*.ko*";
   "libcrc*.ko*";
   "ibmvscsic.ko*";
-- 
2.5.0

Also drop the sr_mod module used by the deprecated guestfs_add_cdrom
interface.
---
 src/ext2_initrd.ml | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/src/ext2_initrd.ml b/src/ext2_initrd.ml
index 730f806..5e841ea 100644
--- a/src/ext2_initrd.ml
+++ b/src/ext2_initrd.ml
@@ -40,12 +40,7 @@ let kmods = [
   "virtio*.ko*";
   "libata*.ko*";
   "piix*.ko*";
-  "scsi_transport_spi.ko*";
-  "scsi_mod.ko*";
-  "sd_mod.ko*";
-  "sym53c8xx.ko*";
   "ata_piix.ko*";
-  "sr_mod.ko*";
   "crc*.ko*";
   "libcrc*.ko*";
   "ibmvscsic.ko*";
-- 
2.5.0

On Thursday 17 March 2016 10:07:34 Richard W.M. Jones
wrote:
> Various patches to make supermin quieter.  By outputting fewer
> messages on the fast path, we use the slow emulated UART less, and
> this improves boot times.
> 
> Also remove some kernel modules that we cannot or should not be using,
> which also improves boot times.
The series LGTM.

Thanks,
-- 
Pino Toscano

On 03/17/2016 12:07, Richard W.M. Jones wrote:
> Also drop the sr_mod module used by the deprecated guestfs_add_cdrom
> interface.
> ---
>  src/ext2_initrd.ml | 5 -----
>  1 file changed, 5 deletions(-)
> 
> diff --git a/src/ext2_initrd.ml b/src/ext2_initrd.ml
> index 730f806..5e841ea 100644
> --- a/src/ext2_initrd.ml
> +++ b/src/ext2_initrd.ml
> @@ -40,12 +40,7 @@ let kmods = [
> -  "sd_mod.ko*";
sd_mod.ko is required on Debian jessie (with kernel from backports
4.3.0-0.bpo.1-amd64), otherwise it won't find /sys/block/sdb/dev.

Best regards,
-- 
Edwin Török | Co-founder and Lead Developer

Skylable open-source object storage: reliable, fast, secure
http://www.skylable.com

On Thu, Mar 17, 2016 at 10:07:34AM +0000, Richard W.M. Jones
wrote:
> Various patches to make supermin quieter.  By outputting fewer
> messages on the fast path, we use the slow emulated UART less, and
> this improves boot times.
> 
> Also remove some kernel modules that we cannot or should not be using,
> which also improves boot times.
Trying to apply this series on current Git master fails for me.

I'm here:

    $ git describe
    v5.1.15-10-gaa720f5

While applying, the first patch ("init: If "quiet" is found on
the
command line, suppress debug output") fails:

    $ git am `git-find-series-in-maildir \
   
~/Mail/RH/libguestfs/cur/1458209606_0.20513.tesla\,U\=1561870\,FMD5\=d735770317fa502b04f5c5707608ec3c\:2\,FS`
    Applying: init: If "quiet" is found on the command line, suppress
debug output.
    error: patch failed: init/init.c:71
    error: init/init.c: patch does not apply
    Patch failed at 0001 init: If "quiet" is found on the command
line, suppress debug output.
    The copy of the patch that failed is found in:
       /home/kashyapc/tinker-space/supermin/.git/rebase-apply/patch
    When you have resolved this problem, run "git am --continue".
    If you prefer to skip this patch, run "git am --skip" instead.
    To restore the original branch and stop patching, run "git am
--abort".

I don't mind applying patche series from list at all for testing, but
just wondering -- have any convenient branch to test?  I quickly checked
on GitHub, but I couldn't your 'supermin' tree there.

-- 
/kashyap

On Mon, Mar 21, 2016 at 07:02:32AM +0100, Kashyap Chamarthy
wrote:
> On Thu, Mar 17, 2016 at 10:07:34AM +0000, Richard W.M. Jones wrote:
> > Various patches to make supermin quieter.  By outputting fewer
> > messages on the fast path, we use the slow emulated UART less, and
> > this improves boot times.
> > 
> > Also remove some kernel modules that we cannot or should not be using,
> > which also improves boot times.
> 
> Trying to apply this series on current Git master fails for me.
> 
> I'm here:
> 
>     $ git describe
>     v5.1.15-10-gaa720f5
> 
> While applying, the first patch ("init: If "quiet" is found
on the
> command line, suppress debug output") fails:
> 
>     $ git am `git-find-series-in-maildir \
>    
~/Mail/RH/libguestfs/cur/1458209606_0.20513.tesla\,U\=1561870\,FMD5\=d735770317fa502b04f5c5707608ec3c\:2\,FS`
>     Applying: init: If "quiet" is found on the command line,
suppress debug output.
>     error: patch failed: init/init.c:71
>     error: init/init.c: patch does not apply
>     Patch failed at 0001 init: If "quiet" is found on the command
line, suppress debug output.
>     The copy of the patch that failed is found in:
>        /home/kashyapc/tinker-space/supermin/.git/rebase-apply/patch
>     When you have resolved this problem, run "git am --continue".
>     If you prefer to skip this patch, run "git am --skip"
instead.
>     To restore the original branch and stop patching, run "git am
--abort".
> 
> I don't mind applying patche series from list at all for testing, but
> just wondering -- have any convenient branch to test?  I quickly checked
> on GitHub, but I couldn't your 'supermin' tree there.
I think it's because I pushed all these patches upstream already.
See:

  https://github.com/libguestfs/supermin

You'll probably find the libguestfs patches for boot analysis more
interesting.  See:

  https://github.com/rwmjones/libguestfs/commits/master

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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