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authorAlexander Gordeev <agordeev@redhat.com>2012-11-19 16:01:29 +0100
committerIngo Molnar <mingo@kernel.org>2013-01-24 17:25:12 +0100
commit51906e779f2b13b38f8153774c4c7163d412ffd9 (patch)
tree970633752f6a5cea156226cd31457289ba16f1c5 /include/linux/irq.h
parent4cca6ea04d31c22a7d0436949c072b27bde41f86 (diff)
x86/MSI: Support multiple MSIs in presense of IRQ remapping
The MSI specification has several constraints in comparison with MSI-X, most notable of them is the inability to configure MSIs independently. As a result, it is impossible to dispatch interrupts from different queues to different CPUs. This is largely devalues the support of multiple MSIs in SMP systems. Also, a necessity to allocate a contiguous block of vector numbers for devices capable of multiple MSIs might cause a considerable pressure on x86 interrupt vector allocator and could lead to fragmentation of the interrupt vectors space. This patch overcomes both drawbacks in presense of IRQ remapping and lets devices take advantage of multiple queues and per-IRQ affinity assignments. Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/c8bd86ff56b5fc118257436768aaa04489ac0a4c.1353324359.git.agordeev@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/irq.h')
-rw-r--r--include/linux/irq.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/irq.h b/include/linux/irq.h
index fdf2c4a238c..1eab99111e9 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -528,6 +528,8 @@ extern int irq_set_handler_data(unsigned int irq, void *data);
extern int irq_set_chip_data(unsigned int irq, void *data);
extern int irq_set_irq_type(unsigned int irq, unsigned int type);
extern int irq_set_msi_desc(unsigned int irq, struct msi_desc *entry);
+extern int irq_set_msi_desc_off(unsigned int irq_base, unsigned int irq_offset,
+ struct msi_desc *entry);
extern struct irq_data *irq_get_irq_data(unsigned int irq);
static inline struct irq_chip *irq_get_chip(unsigned int irq)
@@ -590,6 +592,9 @@ int __irq_alloc_descs(int irq, unsigned int from, unsigned int cnt, int node,
#define irq_alloc_desc_from(from, node) \
irq_alloc_descs(-1, from, 1, node)
+#define irq_alloc_descs_from(from, cnt, node) \
+ irq_alloc_descs(-1, from, cnt, node)
+
void irq_free_descs(unsigned int irq, unsigned int cnt);
int irq_reserve_irqs(unsigned int from, unsigned int cnt);