The patch titled
x86_64 irq: Simplify the vector allocator
has been added to the -mm tree. Its filename is
x86_64-irq-simplify-the-vector-allocator.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: x86_64 irq: Simplify the vector allocator
From: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
There is no reason to remember a per cpu position of which vector to try.
Keeping a global position is simpler and more likely to result in a global
vector allocation even if I don't need or require it. For level triggered
interrupts this means we are less likely to acknowledge another cpus irq,
and cause the level triggered irq to harmlessly refire.
This simplification makes it easier to only access data structures of
online cpus, by having fewer special cases to deal with.
Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Acked-by: Yinghai Lu <yinghai.lu@xxxxxxx>
Acked-by: Muli Ben-Yehuda <muli@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/x86_64/kernel/io_apic.c | 20 +++++++-------------
1 file changed, 7 insertions(+), 13 deletions(-)
diff -puN arch/x86_64/kernel/io_apic.c~x86_64-irq-simplify-the-vector-allocator arch/x86_64/kernel/io_apic.c
--- a/arch/x86_64/kernel/io_apic.c~x86_64-irq-simplify-the-vector-allocator
+++ a/arch/x86_64/kernel/io_apic.c
@@ -612,10 +612,7 @@ static int __assign_irq_vector(int irq,
* Also, we've got to be careful not to trash gate
* 0x80, because int 0x80 is hm, kind of importantish. ;)
*/
- static struct {
- int vector;
- int offset;
- } pos[NR_CPUS] = { [ 0 ... NR_CPUS - 1] = {FIRST_DEVICE_VECTOR, 0} };
+ static int current_vector = FIRST_DEVICE_VECTOR, current_offset = 0;
int old_vector = -1;
int cpu;
@@ -631,14 +628,13 @@ static int __assign_irq_vector(int irq,
for_each_cpu_mask(cpu, mask) {
cpumask_t domain;
- int first, new_cpu;
+ int new_cpu;
int vector, offset;
domain = vector_allocation_domain(cpu);
- first = first_cpu(domain);
- vector = pos[first].vector;
- offset = pos[first].offset;
+ vector = current_vector;
+ offset = current_offset;
next:
vector += 8;
if (vector >= FIRST_SYSTEM_VECTOR) {
@@ -646,7 +642,7 @@ next:
offset = (offset + 1) % 8;
vector = FIRST_DEVICE_VECTOR + offset;
}
- if (unlikely(pos[first].vector == vector))
+ if (unlikely(current_vector == vector))
continue;
if (vector == IA32_SYSCALL_VECTOR)
goto next;
@@ -654,10 +650,8 @@ next:
if (per_cpu(vector_irq, new_cpu)[vector] != -1)
goto next;
/* Found one! */
- for_each_cpu_mask(new_cpu, domain) {
- pos[new_cpu].vector = vector;
- pos[new_cpu].offset = offset;
- }
+ current_vector = vector;
+ current_offset = offset;
if (old_vector >= 0) {
int old_cpu;
for_each_cpu_mask(old_cpu, irq_domain[irq])
_
Patches currently in -mm which might be from ebiederm@xxxxxxxxxxxx are
origin.patch
x86_64-irq-use-irq_domain-in-ioapic_retrigger_irq.patch
x86_64-put-more-than-one-cpu-in-target_cpus.patch
x86_64-irq-simplify-the-vector-allocator.patch
x86_64-irq-only-look-at-per_cpu-data-for-online-cpus.patch
improve-the-remove-sysctl-warnings.patch
add-process_session-helper-routine.patch
rename-struct-namespace-to-struct-mnt_namespace.patch
add-an-identifier-to-nsproxy.patch
rename-struct-pspace-to-struct-pid_namespace.patch
add-pid_namespace-to-nsproxy.patch
use-current-nsproxy-pid_ns.patch
add-child-reaper-to-pid_namespace.patch
rename-struct-namespace-to-struct-mnt_namespace-cachefiles.patch
pidhash-temporary-debug-checks.patch
-
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