> This may be an ancillary effect of what's mentioned above, but when
num_physpages
> grows in size, nr_free_pages doesn't track with it, so in void
vfs_caches_init(unsigned long
> mempages) and the like, you get a horrible underflow condition:
>
> /* code */
> printk("MJS - nr_free_pages():0x%X\n", nr_free_pages());
> printk("MJS - OLD mempages:0x%X\n", mempages);
> reserve = (mempages - nr_free_pages()) * 3/2;
> mempages -= reserve;
> printk("MJS - NEW reserve:0x%X mempages:0x%X\n",
> reserve, mempages);
>
> /* printout */
> MJS - nr_free_pages():0x1E9A0
> MJS - OLD mempages:0x90000
> MJS - NEW reserve:0xAA190 mempages:0xFFFE5E70
I thought I'd wrap up this thread, especially with the HIGHMEM thread still
going around:
http://www.linux-mips.org/archives/linux-mips/2004-12/msg00141.html
The above underflow *was* my problem. I was working in 2.6.6-rc3 before;
with the patch below from 2.6.7-rc1 everything works fine.
# VFS cache sizing fix for small machines
http://linux.bkbits.net:8080/linux-2.6/diffs/fs/dcache.c@xxxx?nav=index.html
|src/|src/fs|hist/fs/dcache.c
# BitKeeper ChangeSet
http://linux.bkbits.net:8080/linux-2.6/cset@xxxxxxxxxxxx?nav=index.html|src/
|src/fs|related/fs/dcache.c
In fs/dcache.c, vfs_caches_init():
< reserve = (mempages - nr_free_pages()) * 3/2;
> reserve = min((mempages - nr_free_pages()) * 3/2, mempages - 1);
Regards,
Matt
----- Original Message -----
From: "Thomas Petazzoni" <thomas.petazzoni@xxxxxxxx>
To: "Matthew Starzewski" <mstarzewski@xxxxxxxxxxx>
Cc: <linux-mips@xxxxxxxxxxxxxx>
Sent: Friday, December 10, 2004 10:10 AM
Subject: Re: Using more than 256 MB of memory on SB1250 in 32-bit mode,
revisited
