* [PATCH] powerpc/prom: bump up maximum size of properties @ 2012-02-25 0:23 Nishanth Aravamudan 2012-02-26 23:22 ` Benjamin Herrenschmidt 0 siblings, 1 reply; 3+ messages in thread From: Nishanth Aravamudan @ 2012-02-25 0:23 UTC (permalink / raw) To: benh; +Cc: linuxppc-dev, Anton Blanchard, Paul Mackerras, Robert Jennings On a 16TB system (using AMS/CMO), I get: WARNING: ignoring large property [/ibm,dynamic-reconfiguration-memory] ibm,dynamic-memory length 0x000000000017ffec and significantly less memory is thus shown to the partition. As far as I can tell, the constant used is arbitrary, but bump it up to 2MB, which covers the above property (approximately 1.5MB). With this patch, the kernel does see all of the system memory on the 16TB system. Signed-off-by: Nishanth Aravamudan <nacc@us•ibm.com> Cc: Anton Blanchard <anton@au1•ibm.com> Cc: Paul Mackerras <paulus@samba•org> Cc: Robert Jennings <rcj@linux•vnet.ibm.com> Cc: linuxppc-dev@lists•ozlabs.org --- arch/powerpc/kernel/prom_init.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c index eca626e..0bf0ccc 100644 --- a/arch/powerpc/kernel/prom_init.c +++ b/arch/powerpc/kernel/prom_init.c @@ -53,7 +53,7 @@ * ensure that we don't lose things like the interrupt-map property * on a PCI-PCI bridge. */ -#define MAX_PROPERTY_LENGTH (1UL * 1024 * 1024) +#define MAX_PROPERTY_LENGTH (2UL * 1024 * 1024) /* * Eventually bump that one up -- 1.7.5.4 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] powerpc/prom: bump up maximum size of properties 2012-02-25 0:23 [PATCH] powerpc/prom: bump up maximum size of properties Nishanth Aravamudan @ 2012-02-26 23:22 ` Benjamin Herrenschmidt 2012-02-27 18:55 ` [PATCH] powerpc/prom: remove limit on " Nishanth Aravamudan 0 siblings, 1 reply; 3+ messages in thread From: Benjamin Herrenschmidt @ 2012-02-26 23:22 UTC (permalink / raw) To: Nishanth Aravamudan Cc: linuxppc-dev, Anton Blanchard, Paul Mackerras, Robert Jennings On Fri, 2012-02-24 at 16:23 -0800, Nishanth Aravamudan wrote: > On a 16TB system (using AMS/CMO), I get: > > WARNING: ignoring large property [/ibm,dynamic-reconfiguration-memory] ibm,dynamic-memory length 0x000000000017ffec > > and significantly less memory is thus shown to the partition. As far as > I can tell, the constant used is arbitrary, but bump it up to 2MB, which > covers the above property (approximately 1.5MB). > > With this patch, the kernel does see all of the system memory on the > 16TB system. Why not go all the way to either removing the limit, or setting it to something much bigger ? That's just asking to break again when we get an even bigger system. The limit was originally set because of Apple machines carrying ROM images in the device-tree, at a time where we were much more memory constrained than we are now. But even then, it never represented such a large gain and in the end, was probably not -that- useful. I'd say bump it to something really large like 16M or remove the limit alltogether. Cheers, Ben. > Signed-off-by: Nishanth Aravamudan <nacc@us•ibm.com> > Cc: Anton Blanchard <anton@au1•ibm.com> > Cc: Paul Mackerras <paulus@samba•org> > Cc: Robert Jennings <rcj@linux•vnet.ibm.com> > Cc: linuxppc-dev@lists•ozlabs.org > --- > arch/powerpc/kernel/prom_init.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c > index eca626e..0bf0ccc 100644 > --- a/arch/powerpc/kernel/prom_init.c > +++ b/arch/powerpc/kernel/prom_init.c > @@ -53,7 +53,7 @@ > * ensure that we don't lose things like the interrupt-map property > * on a PCI-PCI bridge. > */ > -#define MAX_PROPERTY_LENGTH (1UL * 1024 * 1024) > +#define MAX_PROPERTY_LENGTH (2UL * 1024 * 1024) > > /* > * Eventually bump that one up ^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] powerpc/prom: remove limit on maximum size of properties 2012-02-26 23:22 ` Benjamin Herrenschmidt @ 2012-02-27 18:55 ` Nishanth Aravamudan 0 siblings, 0 replies; 3+ messages in thread From: Nishanth Aravamudan @ 2012-02-27 18:55 UTC (permalink / raw) To: Benjamin Herrenschmidt Cc: Nishanth Aravamudan, Anton Blanchard, Paul Mackerras, linuxppc-dev, Robert Jennings Hi Ben, On 27.02.2012 [10:22:14 +1100], Benjamin Herrenschmidt wrote: > On Fri, 2012-02-24 at 16:23 -0800, Nishanth Aravamudan wrote: > > On a 16TB system (using AMS/CMO), I get: > > > > WARNING: ignoring large property [/ibm,dynamic-reconfiguration-memory] ibm,dynamic-memory length 0x000000000017ffec > > > > and significantly less memory is thus shown to the partition. As far as > > I can tell, the constant used is arbitrary, but bump it up to 2MB, which > > covers the above property (approximately 1.5MB). > > > > With this patch, the kernel does see all of the system memory on the > > 16TB system. > > Why not go all the way to either removing the limit, or setting it to > something much bigger ? That's just asking to break again when we get an > even bigger system. Fair point -- sorry, was just trying to get something out the door that I had tested, since I have limited access to the hardware in question. > The limit was originally set because of Apple machines carrying ROM > images in the device-tree, at a time where we were much more memory > constrained than we are now. > > But even then, it never represented such a large gain and in the end, > was probably not -that- useful. > > I'd say bump it to something really large like 16M or remove the limit > alltogether. So, in terms of removing the limit altogether, is that a literal statement? I don't know this code particularly well, but only see references to the constant, at least in prom_init.c: powerpc/prom: remove limit on maximum size of properties On a 16TB system (using AMS/CMO), I get: WARNING: ignoring large property [/ibm,dynamic-reconfiguration-memory] ibm,dynamic-memory length 0x000000000017ffec and significantly less memory is thus shown to the partition. As far as I can tell, the constant used is arbitrary. Ben Herrenschmidt provided additional background that > The limit was originally set because of Apple machines carrying ROM > images in the device-tree, at a time where we were much more memory > constrained than we are now. and that it is likely not very useful any longer. Signed-off-by: Nishanth Aravamudan <nacc@us•ibm.com> --- With this patch, the kernel should see all of the system memory on the 16TB system, but I'm unable to test due to lack of hardware access. I'm working on getting access again, but not confident that will happen soon. diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c index eca626e..e2d5990 100644 --- a/arch/powerpc/kernel/prom_init.c +++ b/arch/powerpc/kernel/prom_init.c @@ -48,14 +48,6 @@ #include <linux/linux_logo.h> /* - * Properties whose value is longer than this get excluded from our - * copy of the device tree. This value does need to be big enough to - * ensure that we don't lose things like the interrupt-map property - * on a PCI-PCI bridge. - */ -#define MAX_PROPERTY_LENGTH (1UL * 1024 * 1024) - -/* * Eventually bump that one up */ #define DEVTREE_CHUNK_SIZE 0x100000 @@ -2273,13 +2265,6 @@ static void __init scan_dt_build_struct(phandle node, unsigned long *mem_start, /* sanity checks */ if (l == PROM_ERROR) continue; - if (l > MAX_PROPERTY_LENGTH) { - prom_printf("WARNING: ignoring large property "); - /* It seems OF doesn't null-terminate the path :-( */ - prom_printf("[%s] ", path); - prom_printf("%s length 0x%x\n", RELOC(pname), l); - continue; - } /* push property head */ dt_push_token(OF_DT_PROP, mem_start, mem_end); -- Nishanth Aravamudan <nacc@us•ibm.com> IBM Linux Technology Center ^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2012-02-27 18:55 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2012-02-25 0:23 [PATCH] powerpc/prom: bump up maximum size of properties Nishanth Aravamudan 2012-02-26 23:22 ` Benjamin Herrenschmidt 2012-02-27 18:55 ` [PATCH] powerpc/prom: remove limit on " Nishanth Aravamudan
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