* [PATCH] adjust BAT mapping according to max_low_mem
@ 2002-02-08 20:36 Val Henson
2002-02-09 20:47 ` Tom Rini
0 siblings, 1 reply; 3+ messages in thread
From: Val Henson @ 2002-02-08 20:36 UTC (permalink / raw)
To: linuxppc-dev
I'm testing highmem by setting max_low_mem to 64MB and using 256MB RAM
total (this does not trigger my SCSI bug). I had to change a few
things in adjust_total_lowmem to force it to _not_ BAT map of all the
RAM. I think the printout of residual is wrong but I'm not sure.
-VAL
# This is a BitKeeper generated patch for the following project:
# Project Name: Linux 2.4 for PowerPC development tree
# This patch format is intended for GNU patch command version 2.5 or higher.
# This patch includes the following deltas:
# ChangeSet 1.201 -> 1.202
# arch/ppc/mm/pgtable.c 1.15 -> 1.16
#
# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/02/08 val@evilcat.fsmlabs.com 1.202
# Fix bat calculations to take into account max_low_mem. This maps only the
# max_low_mem RAM with BATs, so you can test the highmem code on machines with
# less ram. The printout of "residual" is probably wrong, since it now only
# lists the residual lowmem, rather than all residual mem.
# --------------------------------------------
#
diff -Nru a/arch/ppc/mm/pgtable.c b/arch/ppc/mm/pgtable.c
--- a/arch/ppc/mm/pgtable.c Fri Feb 8 13:29:29 2002
+++ b/arch/ppc/mm/pgtable.c Fri Feb 8 13:29:29 2002
@@ -205,7 +205,7 @@
#ifdef HAVE_BATS
unsigned long bat_max = 0x10000000;
unsigned long align;
- unsigned long ram = total_lowmem;
+ unsigned long ram;
int is601 = 0;
/* 601s have smaller BATs */
@@ -213,6 +213,16 @@
bat_max = 0x00800000;
is601 = 1;
}
+
+ /* adjust BAT block size to max_low_mem */
+ if (max_low_mem < bat_max)
+ bat_max = max_low_mem;
+
+ /* adjust lowmem size to max_low_mem */
+ if (max_low_mem < total_lowmem)
+ total_lowmem = max_low_mem;
+
+ ram = total_lowmem;
/* Make sure we don't map a block larger than the
smallest alignment of the physical address. */
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] adjust BAT mapping according to max_low_mem
2002-02-08 20:36 [PATCH] adjust BAT mapping according to max_low_mem Val Henson
@ 2002-02-09 20:47 ` Tom Rini
2002-02-09 21:20 ` Tom Rini
0 siblings, 1 reply; 3+ messages in thread
From: Tom Rini @ 2002-02-09 20:47 UTC (permalink / raw)
To: Val Henson; +Cc: linuxppc-dev
On Fri, Feb 08, 2002 at 01:36:04PM -0700, Val Henson wrote:
> I'm testing highmem by setting max_low_mem to 64MB and using 256MB RAM
> total (this does not trigger my SCSI bug). I had to change a few
> things in adjust_total_lowmem to force it to _not_ BAT map of all the
> RAM. I think the printout of residual is wrong but I'm not sure.
If I'm reading all of the code right, residual at this point should be
(total_lowmem (initial value) - ram mapped in BATs), so I think this:
> + /* adjust BAT block size to max_low_mem */
> + if (max_low_mem < bat_max)
> + bat_max = max_low_mem;
> +
> + /* adjust lowmem size to max_low_mem */
> + if (max_low_mem < total_lowmem)
> + total_lowmem = max_low_mem;
> +
> + ram = total_lowmem;
Should be:
/* adjust BAT block size to max_low_mem */
if (max_low_mem < bat_max)
bat_max = max_low_mem;
/* adjust lowmem size to max_low_mem */
if (max_low_mem < total_lowmem)
ram = max_low_mem;
else
ram = total_lowmem;
...
printk(KERN_INFO "Memory BAT mapping: BAT2=%ldMb, BAT3=%ldMb, "
"residual: %ldMb\n", __bat2 >> 20, __bat3 >> 20,
(total_lowmem - ram) >> 20);
Does this sound right?
--
Tom Rini (TR1265)
http://gate.crashing.org/~trini/
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] adjust BAT mapping according to max_low_mem
2002-02-09 20:47 ` Tom Rini
@ 2002-02-09 21:20 ` Tom Rini
0 siblings, 0 replies; 3+ messages in thread
From: Tom Rini @ 2002-02-09 21:20 UTC (permalink / raw)
To: Val Henson; +Cc: linuxppc-dev
On Sat, Feb 09, 2002 at 01:47:16PM -0700, Tom Rini wrote:
>
> On Fri, Feb 08, 2002 at 01:36:04PM -0700, Val Henson wrote:
>
> > I'm testing highmem by setting max_low_mem to 64MB and using 256MB RAM
> > total (this does not trigger my SCSI bug). I had to change a few
> > things in adjust_total_lowmem to force it to _not_ BAT map of all the
> > RAM. I think the printout of residual is wrong but I'm not sure.
>
> If I'm reading all of the code right, residual at this point should be
> (total_lowmem (initial value) - ram mapped in BATs), so I think this:
>
> > + /* adjust BAT block size to max_low_mem */
> > + if (max_low_mem < bat_max)
> > + bat_max = max_low_mem;
> > +
> > + /* adjust lowmem size to max_low_mem */
> > + if (max_low_mem < total_lowmem)
> > + total_lowmem = max_low_mem;
> > +
> > + ram = total_lowmem;
>
> Should be:
> /* adjust BAT block size to max_low_mem */
> if (max_low_mem < bat_max)
> bat_max = max_low_mem;
>
> /* adjust lowmem size to max_low_mem */
> if (max_low_mem < total_lowmem)
> ram = max_low_mem;
> else
> ram = total_lowmem;
> ...
>
> printk(KERN_INFO "Memory BAT mapping: BAT2=%ldMb, BAT3=%ldMb, "
> "residual: %ldMb\n", __bat2 >> 20, __bat3 >> 20,
> (total_lowmem - ram) >> 20);
And after actually testing:
printk(KERN_INFO "...
(total_lowmem - (__bat2 + __bat3)) >> 20);
If someone else can confirm that the above thinking is right, I'll check
in the following patch, which fixes this and the printk for more RAM
than BATS && !CONFIG_HIGHMEM
--
Tom Rini (TR1265)
http://gate.crashing.org/~trini/
===== arch/ppc/mm/pgtable.c 1.15 vs edited =====
--- 1.15/arch/ppc/mm/pgtable.c Mon Jan 28 04:11:59 2002
+++ edited/arch/ppc/mm/pgtable.c Sat Feb 9 14:07:26 2002
@@ -205,7 +205,7 @@
#ifdef HAVE_BATS
unsigned long bat_max = 0x10000000;
unsigned long align;
- unsigned long ram = total_lowmem;
+ unsigned long ram;
int is601 = 0;
/* 601s have smaller BATs */
@@ -214,6 +214,16 @@
is601 = 1;
}
+ /* adjust BAT block size to max_low_mem */
+ if (max_low_mem < bat_max)
+ bat_max = max_low_mem;
+
+ /* adjust lowmem size to max_low_mem */
+ if (max_low_mem < total_lowmem)
+ ram = max_low_mem;
+ else
+ ram = total_lowmem;
+
/* Make sure we don't map a block larger than the
smallest alignment of the physical address. */
/* alignment of PPC_MEMSTART */
@@ -234,8 +244,9 @@
ram -= __bat3;
}
- printk(KERN_INFO "Memory BAT mapping: BAT2=%ldMb, BAT3=%ldMb, residual: %ldMb\n",
- __bat2 >> 20, __bat3 >> 20, ram >> 20);
+ printk(KERN_INFO "Memory BAT mapping: BAT2=%ldMb, BAT3=%ldMb,"
+ " residual: %ldMb\n", __bat2 >> 20, __bat3 >> 20,
+ (total_lowmem - (__bat2 - __bat3)) >> 20);
/* On SMP, we limit the lowmem to the area mapped with BATs.
* We also assume nobody will do SMP with 601s
@@ -249,8 +260,9 @@
if (total_lowmem > max_low_mem) {
total_lowmem = max_low_mem;
#ifndef CONFIG_HIGHMEM
- printk(KERN_INFO "Warning, memory limited to %ld Mb, use CONFIG_HIGHMEM"
- " to reach %ld Mb\n", max_low_mem >> 20, total_lowmem >> 20);
+ printk(KERN_INFO "Warning, memory limited to %ld Mb, use "
+ " CONFIG_HIGHMEM to reach %ld Mb\n",
+ max_low_mem >> 20, total_memory >> 20);
total_memory = total_lowmem;
#endif /* CONFIG_HIGHMEM */
}
** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/
^ permalink raw reply [flat|nested] 3+ messages in thread
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2002-02-08 20:36 [PATCH] adjust BAT mapping according to max_low_mem Val Henson
2002-02-09 20:47 ` Tom Rini
2002-02-09 21:20 ` Tom Rini
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