The part of the sparsemem patch which modifies memmap_init_zone() has recently
become a problem. It changes behavior so that there is a call to
pfn_to_page() for each individual page inside of a node's range:
node_start_pfn through node_end_pfn. It used to simply do this once, at the
beginning of the node, but having sparsemem's non-contiguous mem_map[]s inside
of a node made it necessary to change.
Mike Kravetz recently wrote a patch which made the NUMA code accept some new
kinds of layouts. The system's memory was laid out like this, with node 0's
memory in two pieces: one before and one after node 1's memory:
Node 0: +++++ +++++
Node 1: +++++
Previous behavior before Mike's patch was to assign nodes like this:
Node 0: 00000 XXXXX
Node 1: 11111
Where the 'X' areas were simply thrown away. The new behavior was to make the
pg_data_t span node 0 across all of its areas, including areas that are really
node 1's: Node 0: 000000000000000 Node 1: 11111
This wastes a little bit of mem_map space, but ends up being OK, and more
fully utilizes the system's memory. memmap_init_zone() initializes all of the
"struct page"s for node 0, even for the "hole", but those never get used,
because there is no pfn_to_page() that resolves to those pages. However, only
calling pfn_to_page() once, memmap_init_zone() always uses the pages that were
allocated for node0->node_mem_map because:
struct page *start = pfn_to_page(start_pfn);
// effectively start = &node->node_mem_map[0]
for (page = start; page < (start + size); page++) {
init_page_here();...
page++;
}
Slow, and wasteful, but generally harmless.
But, modify that to call pfn_to_page() for each loop iteration (like sparsemem
does):
for (pfn = start_pfn; pfn < < (start_pfn + size); pfn++++) {
page = pfn_to_page(pfn);
}
And you end up trying to initialize node 1's pages too early, along with bogus
data from node 0. This patch checks for those weird layouts and declines to
touch the pages, making the more frequent pfn_to_page() calls OK to do.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch changes some of the default behavior in the ppc64 Kconfig file
that was recently changed/added to 2.6.12-rc2-mm1 by Dave Hansen in
preparation for SPARSEMEM. Patch allows the display of both FLAT and
DISCONTIG models on pseries. As before, default is DISCONTIG for SMP and
PSERIES and FLAT for others.
Signed-off-by: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
For all architectures, this just means that you'll see a "Memory Model"
choice in your architecture menu. For those that implement DISCONTIGMEM,
you may eventually want to make your ARCH_DISCONTIGMEM_ENABLE a "def_bool
y" and make your users select DISCONTIGMEM right out of the new choice
menu. The only disadvantage might be if you have some specific things that
you need in your help option to explain something about DISCONTIGMEM.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch allows iSeries to build with CONFIG_PCI=n. This is useful for
partitions that have only virtual I/O.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch enables CONFIG_RTAS_PROC by default on pSeries. This will
preserve /proc/ppc64/rtas/rmo_buffer, which is needed by librtas.
Signed-off-by: John Rose <johnrose@austin.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
While looking at code generated by gcc4.0 I noticed some functions still
had frame pointers, even after we stopped ppc64 from defining
CONFIG_FRAME_POINTER. It turns out kernel/Makefile hardwires
-fno-omit-frame-pointer on when compiling schedule.c.
Create CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER and define it on architectures
that dont require frame pointers in sched.c code.
(akpm: blame me for the name)
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
A bunch of drivers use ISA DMA helpers or their equivalents for
platforms that have ISA with different DMA controller (a lot of ARM
boxen). Currently there is no way to put such dependency in Kconfig -
CONFIG_ISA is not it (e.g. it is not set on platforms that have no ISA
slots, but have on-board devices that pretend to be ISA ones).
New symbol added - ISA_DMA_API. Set when we have functional
enable_dma()/set_dma_mode()/etc. set of helpers. Next patches in the
series will add missing dependencies for drivers that need them.
I'm very carefully staying the hell out of the recurring flamefest on
what exactly CONFIG_ISA would mean in ideal world - added symbol has a
well-defined meaning and for now I really want to treat it as completely
independent from the mess around CONFIG_ISA.
Signed-off-by: Al Viro <viro@parcelfarce.linux.theplanet.co.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
During some code inspection using gcc 4.0 I noticed a stack frame was being
created for a number of functions that didnt require it. For example:
c0000000000df944 <._spin_unlock>:
c0000000000df944: fb e1 ff f0 std r31,-16(r1)
c0000000000df948: f8 21 ff c1 stdu r1,-64(r1)
c0000000000df94c: 7c 3f 0b 78 mr r31,r1
c0000000000df950: 7c 20 04 ac lwsync
c0000000000df954: e8 21 00 00 ld r1,0(r1)
c0000000000df958: 38 00 00 00 li r0,0
c0000000000df95c: 90 03 00 00 stw r0,0(r3)
c0000000000df960: eb e1 ff f0 ld r31,-16(r1)
c0000000000df964: 4e 80 00 20 blr
It turns out we are adding -fno-omit-frame-pointer to ppc64 which is
causing the above behaviour. Removing that flag results in much better
code:
c0000000000d5b30 <._spin_unlock>:
c0000000000d5b30: 7c 20 04 ac lwsync
c0000000000d5b34: 38 00 00 00 li r0,0
c0000000000d5b38: 90 03 00 00 stw r0,0(r3)
c0000000000d5b3c: 4e 80 00 20 blr
We dont require a frame pointer to debug on ppc64, so remove it.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
