On 17.06.2022 12:47, Andrew Cooper wrote:
> This is a continuation of the cleanup and commenting in:
> 9186e96b199e ("x86/pv: Clean up _get_page_type()")
> 8cc5036bc385 ("x86/pv: Fix ABAC cmpxchg() race in _get_page_type()")
>
> With the re-arranged and newly commented logic, it's far more clear that the
> second half of _get_page_type() only has work to do for page validation.
To be honest "far more clear" reads misleading to me: Part of the re-
arrangement was to move later the early setting of PGT_validated for
PGT_writable pages, without which the stated fact wasn't entirely true
prior to the re-arrangement. How about s/far more/now/ ?
> Introduce an early exit for PGT_validated. This makes the fastpath marginally
> faster, and simplifies the subsequent logic as it no longer needs to exclude
> the fully validated case.
>
> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
Preferably with the wording above adjusted:
Reviewed-by: Jan Beulich <jbeul...@suse.com>
> Not that it's relevant, but bloat-o-meter says:
>
> add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-300 (-300)
> Function old new delta
> _get_page_type 6618 6318 -300
>
> which is more impressive than I was expecting.
And I have to admit I'm having trouble seeing why that would be.
Jan
