Eric Lee / linux-smarc-t335x-v3.2

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Commit f6cd24777513fcc673d432cc29ef59881d3e4df1

Authored by Eric Dumazet
Committed by Thomas Gleixner
1 parent 814ce25211
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

irq: Better struct irqaction layout 

We currently use kmalloc-96 slab for struct irqaction allocations on
64bit arches.

This is unfortunate because of possible false sharing and two cache
lines accesses.

Move 'name' and 'dir' fields at the end of the structure, and force a
suitable alignement.

Hot path fields now use one cache line on x86_64.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1288865628.2659.69.camel@edumazet-laptop>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Showing 1 changed file with 3 additions and 3 deletions Side-by-side Diff

include/linux/interrupt.h
Diff comments   View file @ f6cd247
... ... @@ -114,15 +114,15 @@
114 114 struct irqaction {
115 115 irq_handler_t handler;
116 116 unsigned long flags;
117   - const char *name;
118 117 void *dev_id;
119 118 struct irqaction *next;
120 119 int irq;
121   - struct proc_dir_entry *dir;
122 120 irq_handler_t thread_fn;
123 121 struct task_struct *thread;
124 122 unsigned long thread_flags;
125   -};
  123 + const char *name;
  124 + struct proc_dir_entry *dir;
  125 +} ____cacheline_internodealigned_in_smp;
126 126  
127 127 extern irqreturn_t no_action(int cpl, void *dev_id);
128 128