From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 9 Feb 2002 14:20:32 -0700 From: Tom Rini To: Val Henson Cc: linuxppc-dev@lists.linuxppc.org Subject: Re: [PATCH] adjust BAT mapping according to max_low_mem Message-ID: <20020209212032.GD872@opus.bloom.county> References: <20020208133604.H25005@boardwalk> <20020209204716.GA872@opus.bloom.county> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20020209204716.GA872@opus.bloom.county> Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: 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/