Commit Graph

19 Commits

Author SHA1 Message Date
Andi Kleen
ca74a6f84e x86: optimize lock prefix switching to run less frequently
On VMs implemented using JITs that cache translated code changing the lock
prefixes is a quite costly operation that forces the JIT to throw away and
retranslate a lot of code.

Previously a SMP kernel would rewrite the locks once for each CPU which
is quite unnecessary. This patch changes the code to never switch at boot in
 the normal case (SMP kernel booting with >1 CPU) or only once for SMP kernel
on UP.

This makes a significant difference in boot up performance on AMD SimNow!
Also I expect it to be a little faster on native systems too because a smp
switch does a lot of text_poke()s which each synchronize the pipeline.

v1->v2: Rename max_cpus
v1->v2: Fix off by one in UP check (Thomas Gleixner)

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 13:33:17 +01:00
Ingo Molnar
a5fbb6d106 KVM: fix !SMP build error
fix a !SMP build error:

drivers/kvm/kvm_main.c: In function 'kvm_flush_remote_tlbs':
drivers/kvm/kvm_main.c:220: error: implicit declaration of function 'smp_call_function_mask'

(and also avoid unused function warning related to up_smp_call_function()
not making use of the 'func' parameter.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2007-11-09 22:39:38 +01:00
Al Viro
8dfd588c31 smp_call_function_single() should be a macro on UP
... or we end up with header include order problems from hell.

E.g. on m68k this is 100% fatal - local_irq_enable() there
wants preempt_count(), which wants task_struct fields, which
we won't have when we are in smp.h pulled from sched.h.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-17 14:39:19 -07:00
Avi Kivity
a52b1752c0 SMP: Allow smp_call_function_single() to current cpu
This removes the requirement for callers to get_cpu() to check in simple
cases.  This patch is for !CONFIG_SMP.

Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Avi Kivity <avi@qumranet.com>
2007-07-16 12:05:50 +03:00
Heiko Carstens
79974a0e4c Let smp_call_function_single return -EBUSY on UP
All architectures that have an implementation of smp_call_function_single
let it return -EBUSY if it is asked to execute func on the current cpu.
(akpm: except for x86_64).  Therefore the UP version must always return
-EBUSY.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-17 05:23:04 -07:00
Fernando Luis Vazquez Cao
2f4dfe206a Remove hardcoding of hard_smp_processor_id on UP systems
With the advent of kdump, the assumption that the boot CPU when booting an UP
kernel is always the CPU with a particular hardware ID (often 0) (usually
referred to as BSP on some architectures) is not valid anymore.  The reason
being that the dump capture kernel boots on the crashed CPU (the CPU that
invoked crash_kexec), which may be or may not be that particular CPU.

Move definition of hard_smp_processor_id for the UP case to
architecture-specific code ("asm/smp.h") where it belongs, so that each
architecture can provide its own implementation.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Acked-by: Andi Kleen <ak@suse.de>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-09 12:30:48 -07:00
Randy Dunlap
83df8db9e6 [PATCH] declare smp_call_function_single in generic code
smp_call_function_single() needs to be visible in non-SMP builds, to fix:

arch/x86_64/kernel/vsyscall.c:283: warning: implicit declaration of function 'smp_call_function_single'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:38 -08:00
Andrew Morton
a3bc0dbc81 [PATCH] smp_call_function_single() cleanup
If we're going to implement smp_call_function_single() on three architecture
with the same prototype then it should have a declaration in a
non-arch-specific header file.

Move it into <linux/smp.h>.

Cc: Stephane Eranian <eranian@hpl.hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26 08:48:56 -07:00
Andrew Morton
033ab7f8e5 [PATCH] add smp_setup_processor_id()
Presently, smp_processor_id() isn't necessarily set up until setup_arch().
But it's used in boot_cpu_init() and printk() and perhaps in other places,
prior to setup_arch() being called.

So provide a new smp_setup_processor_id() which is called before anything
else, wire it up for Voyager (which boots on a CPU other than #0, and broke).

Cc: James Bottomley <James.Bottomley@steeleye.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-30 11:25:37 -07:00
David Woodhouse
62c4f0a2d5 Don't include linux/config.h from anywhere else in include/
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
2006-04-26 12:56:16 +01:00
Con Kolivas
3c30b06df4 [PATCH] cleanup smp_call_function UP build
net/core/flow.c: In function 'flow_cache_flush':
net/core/flow.c:299: warning: statement with no effect

Signed-off-by: Con Kolivas <kernel@kolivas.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-26 08:56:55 -08:00
Andrew Morton
78eef01b0f [PATCH] on_each_cpu(): disable local interrupts
When on_each_cpu() runs the callback on other CPUs, it runs with local
interrupts disabled.  So we should run the function with local interrupts
disabled on this CPU, too.

And do the same for UP, so the callback is run in the same environment on both
UP and SMP.  (strictly it should do preempt_disable() too, but I think
local_irq_disable is sufficiently equivalent).

Also uninlines on_each_cpu().  softirq.c was the most appropriate file I could
find, but it doesn't seem to justify creating a new file.

Oh, and fix up that comment over (under?) x86's smp_call_function().  It
drives me nuts.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-22 07:53:59 -08:00
Al Viro
1b8623545b [PATCH] remove bogus asm/bug.h includes.
A bunch of asm/bug.h includes are both not needed (since it will get
pulled anyway) and bogus (since they are done too early).  Removed.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2006-02-07 20:56:35 -05:00
Linus Torvalds
2d0ebb3603 Revert "[NET]: Shut up warnings in net/core/flow.c"
This reverts commit af2b4079ab

Changing the #define to an inline function breaks on non-SMP builds,
since wuite a few places in the kernel do not implement the ipi handler
when compiling for UP.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-23 08:44:05 -08:00
Russell King
af2b4079ab [NET]: Shut up warnings in net/core/flow.c
Not really a network problem, more a !SMP issue.

net/core/flow.c:295: warning: statement with no effect

flow.c:295:        smp_call_function(flow_cache_flush_per_cpu, &info, 1, 0);

Fix this by converting the macro to an inline function, which
also increases the typechecking for !SMP builds.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-11-22 14:38:04 -08:00
Linus Torvalds
2ac6608c41 Revert broken "statement with no effect" warning fix
It may shut up gcc, but it also incorrectly changes the semantics of the
smp_call_function() helpers.

You can fix the warning other ways if you are interested (create another
inline function that takes no arguments and returns zero), but
preferably gcc just shouldn't complain about unused return values from
statement expressions in the first place.
2005-07-28 10:34:47 -07:00
Richard Henderson
79a8810221 [PATCH] alpha: fix "statement with no effect" warnings
Apparently gcc 4.0 complains about "({ 0; });", which leads to -Werror
breakage in one of the alpha oprofile modules.

One might could argue that this is a gcc bug, in that statement-expressions
should be considered to be function-like rather than statement-like for the
purposes of this warning.  But it's just as easy to use an inline function
in the first place, side-stepping the issue.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-28 08:39:02 -07:00
Ingo Molnar
39c715b717 [PATCH] smp_processor_id() cleanup
This patch implements a number of smp_processor_id() cleanup ideas that
Arjan van de Ven and I came up with.

The previous __smp_processor_id/_smp_processor_id/smp_processor_id API
spaghetti was hard to follow both on the implementational and on the
usage side.

Some of the complexity arose from picking wrong names, some of the
complexity comes from the fact that not all architectures defined
__smp_processor_id.

In the new code, there are two externally visible symbols:

 - smp_processor_id(): debug variant.

 - raw_smp_processor_id(): nondebug variant. Replaces all existing
   uses of _smp_processor_id() and __smp_processor_id(). Defined
   by every SMP architecture in include/asm-*/smp.h.

There is one new internal symbol, dependent on DEBUG_PREEMPT:

 - debug_smp_processor_id(): internal debug variant, mapped to
                             smp_processor_id().

Also, i moved debug_smp_processor_id() from lib/kernel_lock.c into a new
lib/smp_processor_id.c file.  All related comments got updated and/or
clarified.

I have build/boot tested the following 8 .config combinations on x86:

 {SMP,UP} x {PREEMPT,!PREEMPT} x {DEBUG_PREEMPT,!DEBUG_PREEMPT}

I have also build/boot tested x64 on UP/PREEMPT/DEBUG_PREEMPT.  (Other
architectures are untested, but should work just fine.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-21 18:46:13 -07:00
Linus Torvalds
1da177e4c3 Linux-2.6.12-rc2
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!
2005-04-16 15:20:36 -07:00