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perf/core: Further simplify perf_mmap() 

Perform CSE and such.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20241104135519.354909594@infradead.org
pull/1183/head
Peter Zijlstra 2024-11-04 14:39:25 +01:00 committed by Ingo Molnar
parent 954878377b
commit 0c8a4e4139
1 changed files with 10 additions and 11 deletions
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21
kernel/events/core.c
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@ -6698,9 +6698,18 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
return ret;
vma_size = vma->vm_end - vma->vm_start;
nr_pages = vma_size / PAGE_SIZE;
if (nr_pages > INT_MAX)
return -ENOMEM;
if (vma_size != PAGE_SIZE * nr_pages)
return -EINVAL;
user_extra = nr_pages;
if (vma->vm_pgoff == 0) {
nr_pages = (vma_size / PAGE_SIZE) - 1;
nr_pages -= 1;
/*
* If we have rb pages ensure they're a power-of-two number, so we
@ -6709,9 +6718,6 @@ static int perf_mmap(struct file *file, struct vm_area_struct *vma)
if (nr_pages != 0 && !is_power_of_2(nr_pages))
return -EINVAL;
if (vma_size != PAGE_SIZE * (1 + nr_pages))
return -EINVAL;
WARN_ON_ONCE(event->ctx->parent_ctx);
again:
mutex_lock(&event->mmap_mutex);
@ -6735,8 +6741,6 @@ again:
rb = event->rb;
goto unlock;
}
user_extra = nr_pages + 1;
} else {
/*
* AUX area mapping: if rb->aux_nr_pages != 0, it's already
@ -6748,10 +6752,6 @@ again:
if (!event->rb)
return -EINVAL;
nr_pages = vma_size / PAGE_SIZE;
if (nr_pages > INT_MAX)
return -ENOMEM;
mutex_lock(&event->mmap_mutex);
ret = -EINVAL;
@ -6795,7 +6795,6 @@ again:
}
atomic_set(&rb->aux_mmap_count, 1);
user_extra = nr_pages;
}
user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);