Re: [PATCH] swap= kernel commandline
Hi1 > > Did you try to load an initrd on a low-memory machine? > > It shouldn't work and it probably won't ;) > > You must be really low on memory ;-) > > # zcat initrd.gz | wc -c > 409600 > > (ash, pwd, chroot, pivot_root, smount, and still about 82 kB free.) Your solution requires 400K initrd _plus_ memory for ash and swapon. That might be easily 600K total. Yes I could imagine machine with freemem less than that. However such machines do not usually have swap available. Pavel -- Philips Velo 1: 1"x4"x8", 300gram, 60, 12MB, 40bogomips, linux, mutt, details at http://atrey.karlin.mff.cuni.cz/~pavel/velo/index.html. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] swap= kernel commandline
Eric W. Biederman wrote: > Hmm. What does it take to mount an NFS partition? Mainly Sun RPC :-( > Anyway. All I did was wrote a tiny libc that is just a bunch of > wrappers for syscalls, and some string functions. Certainly a good approach. It's also basically the idea behind newlib, although newlib has more overhead. Ultimately, I want to be able to compile regular Unix/Linux programs out of the box. Right now, this works for a bunch of trivial programs, and it almost works for ash. > Now if glibc wouldn't link in 200k of unused crap when you make a > trivial static binary I'd much prefer to use it... Precisely why I went to newlib ... It's really a pity that glibc is such a monster. > Though I wish it was possible to have a ramfs preloader instead of > initrd. An initramfs would allow me to not even compile in the block > device driver layer, and be more efficient. Hmm, this would be tricky. You could do it by implementing a simple tar file reader in the kernel, which reads from /dev/initrd (well, it's in-kernel representation), but I'm not sure if this buys you that much in the end. (How much overhead is in block devices anyway ?) - Werner -- _ / Werner Almesberger, ICA, EPFL, CH [EMAIL PROTECTED] / /_IN_N_032__Tel_+41_21_693_6621__Fax_+41_21_693_6610_/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
RE: [PATCH] swap= kernel commandline
>= Original Message From [EMAIL PROTECTED] (Eric W. Biederman) = >Werner Almesberger <[EMAIL PROTECTED]> writes: > >> Eric W. Biederman wrote: >> > I have one that loads a second kernel over the network using dhcp >> > to configure it's interface and tftp to fetch the image and boots >> > that is only 20kb uncompressed >> >> Neat ;-) My goal is actually not only size, but also to have a relatively >> normal build environment, e.g. my example is with shared newlib, regular >> ash, and - unfortunately rather wasteful - glibc's ld.so. >> >> But a tftp loader in 20kB is rather good. Now the next challenge is the >> same thing with NFS. Then we can finally kill nfsroot ;-) > >Hmm. What does it take to mount an NFS partition? > >Anyway. All I did was wrote a tiny libc that is just a bunch of >wrappers for syscalls, and some string functions. Then I just wrote >a straight forward C program to do the job. Except for my added >kexec call I can compile with glibc :) > >Now if glibc wouldn't link in 200k of unused crap when you make a >trivial static binary I'd much prefer to use it... > >Though I wish it was possible to have a ramfs preloader instead of >initrd. An initramfs would allow me to not even compile in the block >device driver layer, and be more efficient. > A discussion on l-k two months ago revealed that someone actually had made a patch that took a tarball (masquaraded as an initrd image) and unpacked it into a ramfs. I've got the mail samewhere if you want it. /Anders - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] swap= kernel commandline
Werner Almesberger <[EMAIL PROTECTED]> writes: > Eric W. Biederman wrote: > > I have one that loads a second kernel over the network using dhcp > > to configure it's interface and tftp to fetch the image and boots > > that is only 20kb uncompressed > > Neat ;-) My goal is actually not only size, but also to have a relatively > normal build environment, e.g. my example is with shared newlib, regular > ash, and - unfortunately rather wasteful - glibc's ld.so. > > But a tftp loader in 20kB is rather good. Now the next challenge is the > same thing with NFS. Then we can finally kill nfsroot ;-) Hmm. What does it take to mount an NFS partition? Anyway. All I did was wrote a tiny libc that is just a bunch of wrappers for syscalls, and some string functions. Then I just wrote a straight forward C program to do the job. Except for my added kexec call I can compile with glibc :) Now if glibc wouldn't link in 200k of unused crap when you make a trivial static binary I'd much prefer to use it... Though I wish it was possible to have a ramfs preloader instead of initrd. An initramfs would allow me to not even compile in the block device driver layer, and be more efficient. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] swap= kernel commandline
Eric W. Biederman wrote: > I have one that loads a second kernel over the network using dhcp > to configure it's interface and tftp to fetch the image and boots > that is only 20kb uncompressed Neat ;-) My goal is actually not only size, but also to have a relatively normal build environment, e.g. my example is with shared newlib, regular ash, and - unfortunately rather wasteful - glibc's ld.so. But a tftp loader in 20kB is rather good. Now the next challenge is the same thing with NFS. Then we can finally kill nfsroot ;-) - Werner -- _ / Werner Almesberger, ICA, EPFL, CH [EMAIL PROTECTED] / /_IN_N_032__Tel_+41_21_693_6621__Fax_+41_21_693_6610_/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] swap= kernel commandline
Werner Almesberger <[EMAIL PROTECTED]> writes: > Rik van Riel wrote: > > Did you try to load an initrd on a low-memory machine? > > It shouldn't work and it probably won't ;) > > You must be really low on memory ;-) > > # zcat initrd.gz | wc -c > 409600 > > (ash, pwd, chroot, pivot_root, smount, and still about 82 kB free.) Hmm And that's without trying to be small. I have one that loads a second kernel over the network using dhcp to configure it's interface and tftp to fetch the image and boots that is only 20kb uncompressed Compressed I can fit that and a kernel all in plus a minimal BIOS all in 512K with some room to spare... Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] swap= kernel commandline
Rik van Riel wrote: > Did you try to load an initrd on a low-memory machine? > It shouldn't work and it probably won't ;) You must be really low on memory ;-) # zcat initrd.gz | wc -c 409600 (ash, pwd, chroot, pivot_root, smount, and still about 82 kB free.) - Werner -- _ / Werner Almesberger, ICA, EPFL, CH [EMAIL PROTECTED] / /_IN_N_032__Tel_+41_21_693_6621__Fax_+41_21_693_6610_/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] swap= kernel commandline
On Sat, 18 Nov 2000, Francois romieu wrote: > The Sat, Nov 18, 2000 at 01:46:40PM +0200, Kaj-Michael Lang wrote : > > This patch adds a swap kernel commandline option, so that you can add a > > swap partition before init starts running on a low-memory machine. ^^ > Did you try and add swap from an initrd image ? It should work > and it's already there. Did you try to load an initrd on a low-memory machine? It shouldn't work and it probably won't ;) regards, Rik -- "What you're running that piece of shit Gnome?!?!" -- Miguel de Icaza, UKUUG 2000 http://www.conectiva.com/ http://www.surriel.com/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] swap= kernel commandline
Hi, The Sat, Nov 18, 2000 at 01:46:40PM +0200, Kaj-Michael Lang wrote : > This patch adds a swap kernel commandline option, so that you can add a > swap partition before init starts running on a low-memory machine. Did you try and add swap from an initrd image ? It should work and it's already there. -- Ueimor - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] Please read the FAQ at http://www.tux.org/lkml/
[PATCH] swap= kernel commandline
This patch adds a swap kernel commandline option, so that you can add a
swap partition before init starts running on a low-memory machine.
The patch is against 2.4.0-test11-pre7
This is my first try at a kernel patch so... I hope someone finds it
usefull.
--- init/main.c-2.4.0test11-pre7Sat Nov 18 12:30:59 2000
+++ init/main.c Sat Nov 18 12:35:08 2000
@@ -131,6 +131,7 @@
int root_mountflags = MS_RDONLY;
char *execute_command;
char root_device_name[64];
+char swap_device_name[64];
static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, };
@@ -297,6 +298,25 @@
__setup("root=", root_dev_setup);
+static int __init swap_dev_setup(char *line)
+{
+ int i;
+ char ch;
+
+ memset (swap_device_name, 0, sizeof swap_device_name);
+ for (i = 0; i < sizeof swap_device_name - 1; ++i)
+ {
+ ch = line[i];
+ if ( isspace (ch) || (ch == ',') || (ch == '\0') ) break;
+ swap_device_name[i] = ch;
+ }
+ return 1;
+}
+
+
+__setup("swap=", swap_dev_setup);
+
+
static int __init checksetup(char *line)
{
struct kernel_param *p;
@@ -725,6 +745,15 @@
mount_devfs_fs ();
+ if (swap_device_name[0]!=0) {
+ printk("Setting up swap: %s \n",swap_device_name);
+ if ( sys_swapon(swap_device_name,0)==0 ) {
+ printk("Swapon ok\n");
+ } else {
+ printk("Swapon failed!\n");
+ }
+ }
+
#ifdef CONFIG_BLK_DEV_INITRD
root_mountflags = real_root_mountflags;
if (mount_initrd && ROOT_DEV != real_root_dev
@@ -780,3 +809,4 @@
execve("/bin/sh",argv_init,envp_init);
panic("No init found. Try passing init= option to kernel.");
}
+
