The following patch adds the x86_64 architecture specific implementation
for function return probes.
Function return probes is a mechanism built on top of kprobes that allows
a caller to register a handler to be called when a given function exits.
For example, to instrument the return path of sys_mkdir:
static int sys_mkdir_exit(struct kretprobe_instance *i, struct pt_regs *regs)
{
printk("sys_mkdir exited\n");
return 0;
}
static struct kretprobe return_probe = {
.handler = sys_mkdir_exit,
};
<inside setup function>
return_probe.kp.addr = (kprobe_opcode_t *) kallsyms_lookup_name("sys_mkdir");
if (register_kretprobe(&return_probe)) {
printk(KERN_DEBUG "Unable to register return probe!\n");
/* do error path */
}
<inside cleanup function>
unregister_kretprobe(&return_probe);
The way this works is that:
* At system initialization time, kernel/kprobes.c installs a kprobe
on a function called kretprobe_trampoline() that is implemented in
the arch/x86_64/kernel/kprobes.c (More on this later)
* When a return probe is registered using register_kretprobe(),
kernel/kprobes.c will install a kprobe on the first instruction of the
targeted function with the pre handler set to arch_prepare_kretprobe()
which is implemented in arch/x86_64/kernel/kprobes.c.
* arch_prepare_kretprobe() will prepare a kretprobe instance that stores:
- nodes for hanging this instance in an empty or free list
- a pointer to the return probe
- the original return address
- a pointer to the stack address
With all this stowed away, arch_prepare_kretprobe() then sets the return
address for the targeted function to a special trampoline function called
kretprobe_trampoline() implemented in arch/x86_64/kernel/kprobes.c
* The kprobe completes as normal, with control passing back to the target
function that executes as normal, and eventually returns to our trampoline
function.
* Since a kprobe was installed on kretprobe_trampoline() during system
initialization, control passes back to kprobes via the architecture
specific function trampoline_probe_handler() which will lookup the
instance in an hlist maintained by kernel/kprobes.c, and then call
the handler function.
* When trampoline_probe_handler() is done, the kprobes infrastructure
single steps the original instruction (in this case just a top), and
then calls trampoline_post_handler(). trampoline_post_handler() then
looks up the instance again, puts the instance back on the free list,
and then makes a long jump back to the original return instruction.
So to recap, to instrument the exit path of a function this implementation
will cause four interruptions:
- A breakpoint at the very beginning of the function allowing us to
switch out the return address
- A single step interruption to execute the original instruction that
we replaced with the break instruction (normal kprobe flow)
- A breakpoint in the trampoline function where our instrumented function
returned to
- A single step interruption to execute the original instruction that
we replaced with the break instruction (normal kprobe flow)
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch adds function-return probes to kprobes for the i386
architecture. This enables you to establish a handler to be run when a
function returns.
1. API
Two new functions are added to kprobes:
int register_kretprobe(struct kretprobe *rp);
void unregister_kretprobe(struct kretprobe *rp);
2. Registration and unregistration
2.1 Register
To register a function-return probe, the user populates the following
fields in a kretprobe object and calls register_kretprobe() with the
kretprobe address as an argument:
kp.addr - the function's address
handler - this function is run after the ret instruction executes, but
before control returns to the return address in the caller.
maxactive - The maximum number of instances of the probed function that
can be active concurrently. For example, if the function is non-
recursive and is called with a spinlock or mutex held, maxactive = 1
should be enough. If the function is non-recursive and can never
relinquish the CPU (e.g., via a semaphore or preemption), NR_CPUS should
be enough. maxactive is used to determine how many kretprobe_instance
objects to allocate for this particular probed function. If maxactive <=
0, it is set to a default value (if CONFIG_PREEMPT maxactive=max(10, 2 *
NR_CPUS) else maxactive=NR_CPUS)
For example:
struct kretprobe rp;
rp.kp.addr = /* entrypoint address */
rp.handler = /*return probe handler */
rp.maxactive = /* e.g., 1 or NR_CPUS or 0, see the above explanation */
register_kretprobe(&rp);
The following field may also be of interest:
nmissed - Initialized to zero when the function-return probe is
registered, and incremented every time the probed function is entered but
there is no kretprobe_instance object available for establishing the
function-return probe (i.e., because maxactive was set too low).
2.2 Unregister
To unregiter a function-return probe, the user calls
unregister_kretprobe() with the same kretprobe object as registered
previously. If a probed function is running when the return probe is
unregistered, the function will return as expected, but the handler won't
be run.
3. Limitations
3.1 This patch supports only the i386 architecture, but patches for
x86_64 and ppc64 are anticipated soon.
3.2 Return probes operates by replacing the return address in the stack
(or in a known register, such as the lr register for ppc). This may
cause __builtin_return_address(0), when invoked from the return-probed
function, to return the address of the return-probes trampoline.
3.3 This implementation uses the "Multiprobes at an address" feature in
2.6.12-rc3-mm3.
3.4 Due to a limitation in multi-probes, you cannot currently establish
a return probe and a jprobe on the same function. A patch to remove
this limitation is being tested.
This feature is required by SystemTap (http://sourceware.org/systemtap),
and reflects ideas contributed by several SystemTap developers, including
Will Cohen and Ananth Mavinakayanahalli.
Signed-off-by: Hien Nguyen <hien@us.ibm.com>
Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Signed-off-by: Frederik Deweerdt <frederik.deweerdt@laposte.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Convert a bunch of strdup() implementations and their callers to the new
kstrdup(). A few remain, for example see sound/core, and there are tons of
open coded strdup()'s around. Sigh. But this is a start.
Signed-off-by: Robert Love <rml@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Assignment doesn't make much sense here as condition would always be true.
Signed-off-by: Domen Puncer <domen@coderock.org>
Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make use of the user_mode macro where it's possible. This is useful for Xen
because it will need only to redefine only the macro to a hypervisor call.
Signed-off-by: Vincent Hanquez <vincent.hanquez@cl.cam.ac.uk>
Cc: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add 2 macros to set and get debugreg on x86_64. This is useful for Xen
because it will need only to redefine each macro to a hypervisor call.
Signed-off-by: Vincent Hanquez <vincent.hanquez@cl.cam.ac.uk>
Cc: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use the user_mode macro where it's possible.
Signed-off-by: Vincent Hanquez <vincent.hanquez@cl.cam.ac.uk>
Cc: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Rename user_mode to user_mode_vm and add a user_mode macro similar to the
x86-64 one.
This is useful for Xen because the linux xen kernel does not runs on the same
priviledge that a vanilla linux kernel, and with this we just need to redefine
user_mode().
Signed-off-by: Vincent Hanquez <vincent.hanquez@cl.cam.ac.uk>
Cc: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make use of the 2 new macro set_debugreg and get_debugreg.
Signed-off-by: Vincent Hanquez <vincent.hanquez@cl.cam.ac.uk>
Cc: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I suggest to change the way IRQs are handed out to PCI devices.
Currently, each I/O APIC pin gets associated with an IRQ, no matter if the
pin is used or not. It is expected that each pin can potentually be
engaged by a device inserted into the corresponding PCI slot. However,
this imposes severe limitation on systems that have designs that employ
many I/O APICs, only utilizing couple lines of each, such as P64H2 chipset.
It is used in ES7000, and currently, there is no way to boot the system
with more that 9 I/O APICs.
The simple change below allows to boot a system with say 64 (or more) I/O
APICs, each providing 1 slot, which otherwise impossible because of the IRQ
gaps created for unused lines on each I/O APIC. It does not resolve the
problem with number of devices that exceeds number of possible IRQs, but
eases up a tension for IRQs on any large system with potentually large
number of devices.
I only implemented this for the ACPI boot, since if the system is this big
and using newer chipsets it is probably (better be!) an ACPI based system
:). The change is completely "mechanical" and does not alter any internal
structures or interrupt model/implementation. The patch works for both
i386 and x86_64 archs. It works with MSIs just fine, and should not
intervene with implementations like shared vectors, when they get worked
out and incorporated.
To illustrate, below is the interrupt distribution for 2-cell ES7000 with
20 I/O APICs, and an Ethernet card in the last slot, which should be eth1
and which was not configured because its IRQ exceeded allowable number (it
actially turned out huge - 480!):
zorro-tb2:~ # cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
0: 65716 30012 30007 30002 30009 30010 30010 30010 IO-APIC-edge timer
4: 373 0 725 280 0 0 0 0 IO-APIC-edge serial
8: 0 0 0 0 0 0 0 0 IO-APIC-edge rtc
9: 0 0 0 0 0 0 0 0 IO-APIC-level acpi
14: 39 3 0 0 0 0 0 0 IO-APIC-edge ide0
16: 108 13 0 0 0 0 0 0 IO-APIC-level uhci_hcd:usb1
18: 0 0 0 0 0 0 0 0 IO-APIC-level uhci_hcd:usb3
19: 15 0 0 0 0 0 0 0 IO-APIC-level uhci_hcd:usb2
23: 3 0 0 0 0 0 0 0 IO-APIC-level ehci_hcd:usb4
96: 4240 397 18 0 0 0 0 0 IO-APIC-level aic7xxx
97: 15 0 0 0 0 0 0 0 IO-APIC-level aic7xxx
192: 847 0 0 0 0 0 0 0 IO-APIC-level eth0
NMI: 0 0 0 0 0 0 0 0
LOC: 273423 274528 272829 274228 274092 273761 273827 273694
ERR: 7
MIS: 0
Even though the system doesn't have that many devices, some don't get
enabled only because of IRQ numbering model.
This is the IRQ picture after the patch was applied:
zorro-tb2:~ # cat /proc/interrupts
CPU0 CPU1 CPU2 CPU3 CPU4 CPU5 CPU6 CPU7
0: 44169 10004 10004 10001 10004 10003 10004 6135 IO-APIC-edge timer
4: 345 0 0 0 0 244 0 0 IO-APIC-edge serial
8: 0 0 0 0 0 0 0 0 IO-APIC-edge rtc
9: 0 0 0 0 0 0 0 0 IO-APIC-level acpi
14: 39 0 3 0 0 0 0 0 IO-APIC-edge ide0
17: 4425 0 9 0 0 0 0 0 IO-APIC-level aic7xxx
18: 15 0 0 0 0 0 0 0 IO-APIC-level aic7xxx, uhci_hcd:usb3
21: 231 0 0 0 0 0 0 0 IO-APIC-level uhci_hcd:usb1
22: 26 0 0 0 0 0 0 0 IO-APIC-level uhci_hcd:usb2
23: 3 0 0 0 0 0 0 0 IO-APIC-level ehci_hcd:usb4
24: 348 0 0 0 0 0 0 0 IO-APIC-level eth0
25: 6 192 0 0 0 0 0 0 IO-APIC-level eth1
NMI: 0 0 0 0 0 0 0 0
LOC: 107981 107636 108899 108698 108489 108326 108331 108254
ERR: 7
MIS: 0
Not only we see the card in the last I/O APIC, but we are not even close to
using up available IRQs, since we didn't waste any.
Signed-off-by: Natalie Protasevich <Natalie.Protasevich@unisys.com>
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This is the x86_64 version of the signal fix I just posted for i386.
This problem was first noticed on PPC and has already been fixed there.
But the exact same issue applies to other platforms in the same way. The
signal blocking for sa_mask and the handled signal takes place after the
handler setup. When the stack is bogus, the handler setup forces a
SIGSEGV. But then this will be blocked, and returning to user mode will
fault again and iterate. This patch fixes the problem by checking whether
signal handler setup failed, and not doing the signal-blocking if so. This
copies what was done in the ppc code. I think all architectures' signal
handler setup code follows this pattern and needs the change.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently the x86-64 HPET code assumes the entire HPET implementation from
the spec is present. This breaks on boxes that do not implement the
optional legacy timer replacement functionality portion of the spec.
This patch fixes this issue, allowing x86-64 systems that cannot use the
HPET for the timer interrupt and RTC to still use the HPET as a time
source. I've tested this patch on a system systems without HPET, with HPET
but without legacy timer replacement, as well as HPET with legacy timer
replacement.
This version adds a minor check to cap the HPET counter value in
gettimeoffset_hpet to avoid possible time inconsistencies. Please ignore
the A2 version I sent to you earlier.
Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
x86_64's cpu_khz is unsigned int and there is no reason why x86 needs to use
unsigned long.
So make cpu_khz unsigned int on x86 as well.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* EXPORT_SYMBOL's moved to other files
* #include <linux/config.h>, <linux/module.h> where needed
* #include's in i386_ksyms.c cleaned up
* After copy-paste, redundant due to Makefiles rules preprocessor directives
removed:
#ifdef CONFIG_FOO
EXPORT_SYMBOL(foo);
#endif
obj-$(CONFIG_FOO) += foo.o
* Tiny reformat to fit in 80 columns
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
According to the VIA 82C586B datasheet (still available from
http://gkernel.sourceforge.net/specs/via/586b.pdf.bz2) this chip need a
special PIRQ mapping.
Signed-off-by: Karsten Keil <kkeil@suse.de>
Signed-off-by: Aleksey Gorelov <aleksey_gorelov@phoenix.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I have submitted the patch for x86_64, this is submission for i386.
The patch changes the way IRQs are handed out to PCI devices. Currently,
each I/O APIC pin gets associated with an IRQ, no matter if the pin is used
or not. This imposes severe limitation on systems that have designs that
employ many I/O APICs, only utilizing couple lines of each, such as P64H2
chipset. It is used in ES7000, and currently, there is no way to boot the
system with more that 9 I/O APICs.
The simple change below allows to boot a system with say 64 (or more) I/O
APICs, each providing 1 slot, which otherwise impossible because of the IRQ
gaps created for unused lines on each I/O APIC. It does not resolve the
problem with number of devices that exceeds number of possible IRQs, but
eases up a tension for IRQs on any large system with potentually large
number of devices.
Signed-off-by: Natalie Protasevich <Natalie.Protasevich@unisys.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It allows a selectable timer interrupt frequency of 100, 250 and 1000 HZ.
Reducing the timer frequency may have important performance benefits on
large systems.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make the timer frequency selectable. The timer interrupt may cause bus
and memory contention in large NUMA systems since the interrupt occurs
on each processor HZ times per second.
Signed-off-by: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Allow early printk code to take advantage of the full size of the screen, not
just the first 25 lines.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Get the i386 watchdog tick calculation into a state where it can also be used
on CPUs with frequencies beyond 4GHz, and it consolidates the calculation into
a single place (for potential furture adjustments).
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch is per Andi's request to remove NO_IOAPIC_CHECK from genapic and
use heuristics to prevent unique I/O APIC ID check for systems that don't
need it. The patch disables unique I/O APIC ID check for Xeon-based and
other platforms that don't use serial APIC bus for interrupt delivery.
Andi stated that AMD systems don't need unique IO_APIC_IDs either.
Signed-off-by: Natalie Protasevich <Natalie.Protasevich@unisys.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This problem was first noticed on PPC and has already been fixed there.
But the exact same issue applies to other platforms in the same way. The
signal blocking for sa_mask and the handled signal takes place after the
handler setup. When the stack is bogus, the handler setup forces a
SIGSEGV. But then this will be blocked, and returning to user mode will
fault again and iterate. This patch fixes the problem by checking whether
signal handler setup failed, and not doing the signal-blocking if so. This
copies what was done in the ppc code. I think all architectures' signal
handler setup code follows this pattern and needs the change.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Define pcibus_to_node to be able to figure out which NUMA node contains a
given PCI device. This defines pcibus_to_node(bus) in
include/linux/topology.h and adjusts the macros for i386 and x86_64 that
already provided a way to determine the cpumask of a pci device.
x86_64 was changed to not build an array of cpumasks anymore. Instead an
array of nodes is build which can be used to generate the cpumask via
node_to_cpumask.
Signed-off-by: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Issue:
Current tsc based delay_calibration can result in significant errors in
loops_per_jiffy count when the platform events like SMIs
(System Management Interrupts that are non-maskable) are present. This could
lead to potential kernel panic(). This issue is becoming more visible with 2.6
kernel (as default HZ is 1000) and on platforms with higher SMI handling
latencies. During the boot time, SMIs are mostly used by BIOS (for things
like legacy keyboard emulation).
Description:
The psuedocode for current delay calibration with tsc based delay looks like
(0) Estimate a value for loops_per_jiffy
(1) While (loops_per_jiffy estimate is accurate enough)
(2) wait for jiffy transition (jiffy1)
(3) Note down current tsc (tsc1)
(4) loop until tsc becomes tsc1 + loops_per_jiffy
(5) check whether jiffy changed since jiffy1 or not and refine
loops_per_jiffy estimate
Consider the following cases
Case 1:
If SMIs happen between (2) and (3) above, we can end up with a
loops_per_jiffy value that is too low. This results in shorted delays and
kernel can panic () during boot (Mostly at IOAPIC timer initialization
timer_irq_works() as we don't have enough timer interrupts in a specified
interval).
Case 2:
If SMIs happen between (3) and (4) above, then we can end up with a
loops_per_jiffy value that is too high. And with current i386 code, too
high lpj value (greater than 17M) can result in a overflow in
delay.c:__const_udelay() again resulting in shorter delay and panic().
Solution:
The patch below makes the calibration routine aware of asynchronous events
like SMIs. We increase the delay calibration time and also identify any
significant errors (greater than 12.5%) in the calibration and notify it to
user.
Patch below changes both i386 and x86-64 architectures to use this
new and improved calibrate_delay_direct() routine.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.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>
The attached patch causes the various arch specific install.sh scripts to
look for ${CROSS_COMPILE}installkernel rather than just installkernel (in
both /sbin/ and ~/bin/ where the script already did this). This allows you
to have e.g. arm-linux-installkernel as a handy way to install on your
cross target. It also prevents the script picking up on the host
/sbin/installkernel which causes the script to fall through and do the
install itself (which is what I actually use myself, with $INSTALL_PATH
set).
I don't believe it causes back-compatibility problems since calling the
host installkernel was never likely to work or be what you wanted when
cross compiling anyway. If $CROSS_COMPILE isn't set then nothing changes.
I only use ARM and i386 myself but I figured it couldn't hurt to do the
whole lot. I've cc'd those who I hope are the arch maintainers for files
that I've touched.
Signed-off-by: Ian Campbell <icampbell@arcom.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This allows the i386 architecture to be built on a system with a biarch
compiler that defaults to x86-64, merely by specifying ARCH=i386.
As previously discussed, this uses the equivalent logic to the ppc port.
Signed-Off-By: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This helps a lot when debugging out of memory stuff - useful especially to
see if all the memory is sucked into slab, etc.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch adds in the necessary support for sparsemem such that x86-64
kernels may use sparsemem as an alternative to discontigmem for NUMA
kernels. Note that this does no preclude one from continuing to build NUMA
kernels using discontigmem, but merely allows the option to build NUMA
kernels with sparsemem.
Interestingly, the use of sparsemem in lieu of discontigmem in NUMA kernels
results in reduced text size for otherwise equivalent kernels as shown in
the example builds below:
text data bss dec hex filename
2371036 765884 1237108 4374028 42be0c vmlinux.discontig
2366549 776484 1302772 4445805 43d66d vmlinux.sparse
Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In order to use the alternative sparsemem implmentation for NUMA kernels,
we need to reorganize the config options. This patch effectively abstracts
out the CONFIG_DISCONTIGMEM options to CONFIG_NUMA in most cases. Thus,
the discontigmem implementation may be employed as always, but the
sparsemem implementation may be used alternatively.
Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add the requisite arch specific Kconfig options to enable the use of the
sparsemem implementation for NUMA kernels on x86-64.
Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch pulls out all remaining direct references to contig_page_data
from arch/x86-64, thus saving an ifdef in one case.
Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Provide the architecture specific implementation for SPARSEMEM for PPC64
systems.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Mike Kravetz <kravetz@us.ibm.com> (in part)
Signed-off-by: Martin Bligh <mbligh@aracnet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Provide hooks for PPC64 to allow memory models to be informed of installed
memory areas. This allows SPARSEMEM to instantiate mem_map for the populated
areas.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Martin Bligh <mbligh@aracnet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Provide an implementation of early_pfn_to_nid for PPC64. This is used by
memory models to determine the node from which to take allocations before the
memory allocators are fully initialised.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Martin Bligh <mbligh@aracnet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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>
Provide the architecture specific implementation for SPARSEMEM for i386 SMP
and NUMA systems.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Martin Bligh <mbligh@aracnet.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>
Sparsemem abstracts the use of discontiguous mem_maps[]. This kind of
mem_map[] is needed by discontiguous memory machines (like in the old
CONFIG_DISCONTIGMEM case) as well as memory hotplug systems. Sparsemem
replaces DISCONTIGMEM when enabled, and it is hoped that it can eventually
become a complete replacement.
A significant advantage over DISCONTIGMEM is that it's completely separated
from CONFIG_NUMA. When producing this patch, it became apparent in that NUMA
and DISCONTIG are often confused.
Another advantage is that sparse doesn't require each NUMA node's ranges to be
contiguous. It can handle overlapping ranges between nodes with no problems,
where DISCONTIGMEM currently throws away that memory.
Sparsemem uses an array to provide different pfn_to_page() translations for
each SECTION_SIZE area of physical memory. This is what allows the mem_map[]
to be chopped up.
In order to do quick pfn_to_page() operations, the section number of the page
is encoded in page->flags. Part of the sparsemem infrastructure enables
sharing of these bits more dynamically (at compile-time) between the
page_zone() and sparsemem operations. However, on 32-bit architectures, the
number of bits is quite limited, and may require growing the size of the
page->flags type in certain conditions. Several things might force this to
occur: a decrease in the SECTION_SIZE (if you want to hotplug smaller areas of
memory), an increase in the physical address space, or an increase in the
number of used page->flags.
One thing to note is that, once sparsemem is present, the NUMA node
information no longer needs to be stored in the page->flags. It might provide
speed increases on certain platforms and will be stored there if there is
room. But, if out of room, an alternate (theoretically slower) mechanism is
used.
This patch introduces CONFIG_FLATMEM. It is used in almost all cases where
there used to be an #ifndef DISCONTIG, because SPARSEMEM and DISCONTIGMEM
often have to compile out the same areas of code.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Martin Bligh <mbligh@aracnet.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Allow architectures to indicate that they will be providing hooks to indice
installed memory areas, memory_present(). Provide prototypes for the i386
implementation.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Martin Bligh <mbligh@aracnet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Provide a default implementation for early_pfn_to_nid returning node 0. Allow
architectures to override this with their own implementation out of
asm/mmzone.h.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Martin Bligh <mbligh@aracnet.com>
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>
This used to be used to disable FLATMEM selection, but I decided to change it
to be done generically when DISCONTIG is enabled. The option is unused, so
this kills it.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This will at least suppress one prompt that users would have received the
first time they compile with the new DISCONTIG arch option. They'll still
get the "Memory Model" prompt, but 99% of them will have the default work
there.
Signed-off-by: Dave Hansen <haveblue@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>
discontig.c has some assumptions that mem_map[]s inside of a node are
contiguous. Teach it to make sure that each region that it's bringing online
is actually made up of valid ranges of ram.
Written-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Introduce a simple allocator for the NUMA remap space. This space is very
scarce, used for structures which are best allocated node local.
This mechanism is also used on non-NUMA ia64 systems with a vmem_map to keep
the pgdat->node_mem_map initialized in a consistent place for all
architectures.
Issues:
o alloc_remap takes a node_id where we might expect a pgdat which was intended
to allow us to allocate the pgdat's using this mechanism; which we do not yet
do. Could have alloc_remap_node() and alloc_remap_nid() for this purpose.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The following four patches provide the last needed changes before the
introduction of sparsemem. For a more complete description of what this
will do, please see this patch:
http://www.sr71.net/patches/2.6.11/2.6.11-bk7-mhp1/broken-out/B-sparse-150-sparsemem.patch
or previous posts on the subject:
http://marc.theaimsgroup.com/?t=110868540700001&r=1&w=2http://marc.theaimsgroup.com/?l=linux-mm&m=109897373315016&w=2
Three of these are i386-only, but one of them reorganizes the macros
used to manage the space in page->flags, and will affect all platforms.
There are analogous patches to the i386 ones for ppc64, ia64, and
x86_64, but those will be submitted by the normal arch maintainers.
The combination of the four patches has been test-booted on a variety of
i386 hardware, and compiled for ppc64, i386, and x86-64 with about 17
different .configs. It's also been runtime-tested on ia64 configs (with
more patches on top).
This patch:
We _know_ which node pages in general belong to, at least at a very gross
level in node_{start,end}_pfn[]. Use those to target the allocations of
pages.
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch effectively eliminates direct use of pgdat->node_mem_map outside
of the DISCONTIG code. On a flat memory system, these fields aren't
currently used, neither are they on a sparsemem system.
There was also a node_mem_map(nid) macro on many architectures. Its use
along with the use of ->node_mem_map itself was not consistent. It has
been removed in favor of two new, more explicit, arch-independent macros:
pgdat_page_nr(pgdat, pagenr)
nid_page_nr(nid, pagenr)
I called them "pgdat" and "nid" because we overload the term "node" to mean
"NUMA node", "DISCONTIG node" or "pg_data_t" in very confusing ways. I
believe the newer names are much clearer.
These macros can be overridden in the sparsemem case with a theoretically
slower operation using node_start_pfn and pfn_to_page(), instead. We could
make this the only behavior if people want, but I don't want to change too
much at once. One thing at a time.
This patch removes more code than it adds.
Compile tested on alpha, alpha discontig, arm, arm-discontig, i386, i386
generic, NUMAQ, Summit, ppc64, ppc64 discontig, and x86_64. Full list
here: http://sr71.net/patches/2.6.12/2.6.12-rc1-mhp2/configs/
Boot tested on NUMAQ, x86 SMP and ppc64 power4/5 LPARs.
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Martin J. Bligh <mbligh@aracnet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Rusty Lynch
Hien Nguyen
Robert Love
Domen Puncer
Vincent Hanquez
Natalie Protasevich
Roland McGrath
john stultz
Alexander Nyberg
Andrew Morton
Alexey Dobriyan
Aleksey Gorelov
Christoph Lameter
Christoph Lameter
Jan Beulich
Venkatesh Pallipadi
Ian Campbell
H. Peter Anvin
Martin J. Bligh
Matt Tolentino
Andy Whitcroft
Mike Kravetz
Dave Hansen
Linus Torvalds