Re: [PATCH v1 03/11] perf: Allow for multiple ring buffers per event

[Dave Hansen]

On 02/17/2014 06:33 AM, Peter Zijlstra wrote:
> Then write the PERF_RECORD_DATA structure into the normal ring-buffer
> location; set data_offset to point to the first page boundary, data_size
> to 1mb.
> 
> Then frob things such that perf_mmap_to_page() for the next 1mb of pages
> points to your buffer pages and wipe the page-table entries.

Wouldn't we have to teach a ton of code how to be IRQ safe for this to
work?  Just step one: how do we go modifying page tables safely from an
interrupt?  mm->page_table_lock is a plain non-irq spinlock.
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