Re: [PATCH RFC 3/4] mm, slab: add static key for should_failslab()
From: Roman Gushchin <roman.gushchin@linux.dev>
Date: 2024-05-31 23:44:26
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bpf, linux-mm, lkml
On Fri, May 31, 2024 at 11:33:34AM +0200, Vlastimil Babka wrote:
Since commit 4f6923fbb352 ("mm: make should_failslab always available for
fault injection") should_failslab() is unconditionally a noinline
function. This adds visible overhead to the slab allocation hotpath,
even if the function is empty. With CONFIG_FAILSLAB=y there's additional
overhead when the functionality is not enabled by a boot parameter or
debugfs.
The overhead can be eliminated with a static key around the callsite.
Fault injection and error injection frameworks can now be told that the
this function has a static key associated, and are able to enable and
disable it accordingly.
Signed-off-by: Vlastimil Babka <redacted>Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>