Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fix from Thomas Gleixner:
"A single fix for the new matrix allocator to prevent vector exhaustion
by certain network drivers which allocate gazillions of unused vectors
which cannot be put into reservation mode due to MSI and the lack of
MSI entry masking.
The fix/workaround is to spread the vectors across CPUs by searching
the supplied target CPU mask for the CPU with the smallest number of
allocated vectors"
* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irq/matrix: Spread interrupts on allocation
+14
-6
+14
-6
kernel/irq/matrix.c
+14
-6
kernel/irq/matrix.c
···
321
321
int irq_matrix_alloc(struct irq_matrix *m, const struct cpumask *msk,
322
322
bool reserved, unsigned int *mapped_cpu)
323
323
{
324
-
unsigned int cpu;
324
+
unsigned int cpu, best_cpu, maxavl = 0;
325
+
struct cpumap *cm;
326
+
unsigned int bit;
325
327
328
+
best_cpu = UINT_MAX;
326
329
for_each_cpu(cpu, msk) {
327
-
struct cpumap *cm = per_cpu_ptr(m->maps, cpu);
328
-
unsigned int bit;
330
+
cm = per_cpu_ptr(m->maps, cpu);
329
331
330
-
if (!cm->online)
332
+
if (!cm->online || cm->available <= maxavl)
331
333
continue;
332
334
335
+
best_cpu = cpu;
336
+
maxavl = cm->available;
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+
}
338
+
339
+
if (maxavl) {
340
+
cm = per_cpu_ptr(m->maps, best_cpu);
333
341
bit = matrix_alloc_area(m, cm, 1, false);
334
342
if (bit < m->alloc_end) {
335
343
cm->allocated++;
···
346
338
m->global_available--;
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339
if (reserved)
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340
m->global_reserved--;
349
-
*mapped_cpu = cpu;
350
-
trace_irq_matrix_alloc(bit, cpu, m, cm);
341
+
*mapped_cpu = best_cpu;
342
+
trace_irq_matrix_alloc(bit, best_cpu, m, cm);
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343
return bit;
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344
}
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345
}