diff options
| author | H. Peter Anvin <hpa@zytor.com> | 2010-01-04 21:14:41 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2010-01-04 21:28:24 -0800 |
| commit | ea94396629a3e0cb9a3a9c75335b1de255b30426 (patch) | |
| tree | 32208d082a54a3069170195c1d046e95620ebd8f /arch/x86/kernel/apic/io_apic.c | |
| parent | 99d113b17e8ca5a8b68a9d3f7691e2f552dd6a06 (diff) | |
x86, apic: Don't waste a vector to improve vector spread
We want to use a vector-assignment sequence that avoids stumbling onto
0x80 earlier in the sequence, in order to improve the spread of
vectors across priority levels on machines with a small number of
interrupt sources. Right now, this is done by simply making the first
vector (0x31 or 0x41) completely unusable. This is unnecessary; all
we need is to start assignment at a +1 offset, we don't actually need
to prohibit the usage of this vector once we have wrapped around.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <4B426550.6000209@kernel.org>
Diffstat (limited to 'arch/x86/kernel/apic/io_apic.c')
| -rw-r--r-- | arch/x86/kernel/apic/io_apic.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index d9cd1f1b9c0..e9ba0903e9d 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1162,7 +1162,8 @@ __assign_irq_vector(int irq, struct irq_cfg *cfg, const struct cpumask *mask) * Also, we've got to be careful not to trash gate * 0x80, because int 0x80 is hm, kind of importantish. ;) */ - static int current_vector = FIRST_DEVICE_VECTOR, current_offset = 0; + static int current_vector = FIRST_DEVICE_VECTOR + VECTOR_OFFSET_START; + static int current_offset = VECTOR_OFFSET_START % 8; unsigned int old_vector; int cpu, err; cpumask_var_t tmp_mask; |