how long does it take to init the scheduler?

[Olaf Hering <olh@suse.de>]

Hi,

the patch below looks wrong to me. Why did you move it to the very end
of the boot process, instead to the very end of start_kernel()?

Now drivers will find an empty rootfs. A few of them do want to read
files from there. They cant currently use the call_usermodehelper
interface because this one checks for system_state. So they have to use
sys_open(). But either way, they will not get anything with 2.6.6.

populate_rootfs() should run before do_initcalls().



#date: 2004-04-21
#id: 1.1371.737.7
#tag: via-mm
#time: 07:42:18
#title: Call populate_rootfs later in boot
#who: akpm@osdl.org[torvalds]
#
# ChangeSet
#   1.1371.737.7 04/04/21 07:42:18 akpm@osdl.org[torvalds] +1 -0
#   [PATCH] Call populate_rootfs later in boot
#   
#   populate_rootfs() is called rather early - before we've called init_idle().
#   
#   But populate_rootfs() does file I/O, which involves calls to cond_resched(),
#   and downing of semaphores, etc.  If it scheules, the scheduler emits
#   scheduling-while-atomic warnings and sometimes oopses.
#   
#   So run populate_rootfs() later, after the scheduler is all set up.
#
# init/main.c +10 -11
#
diff -Nru a/init/main.c b/init/main.c
--- a/init/main.c	Wed Apr 28 10:54:47 2004
+++ b/init/main.c	Wed Apr 28 10:54:48 2004
@@ -89,6 +89,7 @@
 extern void free_initmem(void);
 extern void populate_rootfs(void);
 extern void driver_init(void);
+extern void prepare_namespace(void);
 
 #ifdef CONFIG_TC
 extern void tc_init(void);
@@ -471,7 +472,6 @@
 	signals_init();
 	/* rootfs populating might need page-writeback */
 	page_writeback_init();
-	populate_rootfs();
 #ifdef CONFIG_PROC_FS
 	proc_root_init();
 #endif
@@ -577,8 +577,6 @@
 	execve(init_filename, argv_init, envp_init);
 }
 
-extern void prepare_namespace(void);
-
 static int init(void * unused)
 {
 	lock_kernel();
@@ -600,14 +598,15 @@
 	smp_init();
 	do_basic_setup();
 
-       /*
-        * check if there is an early userspace init, if yes
-        * let it do all the work
-        */
-       if (sys_access("/init", 0) == 0)
-               execute_command = "/init";
-       else
-	prepare_namespace();
+	populate_rootfs();
+	/*
+	 * check if there is an early userspace init.  If yes, let it do all
+	 * the work
+	 */
+	if (sys_access("/init", 0) == 0)
+		execute_command = "/init";
+	else
+		prepare_namespace();
 
 	/*
 	 * Ok, we have completed the initial bootup, and
-- 
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