mm/page_alloc.c: allow error injection
Model call chain after should_failslab(). Likewise, we can now use a kprobe to override the return value of should_fail_alloc_page() and inject allocation failures into alloc_page*(). This will allow injecting allocation failures using the BCC tools even without building kernel with CONFIG_FAIL_PAGE_ALLOC and booting it with a fail_page_alloc= parameter, which incurs some overhead even when failures are not being injected. On the other hand, this patch adds an unconditional call to should_fail_alloc_page() from page allocation hotpath. That overhead should be rather negligible with CONFIG_FAIL_PAGE_ALLOC=n when there's no kprobe attached, though. [vbabka@suse.cz: changelog addition] Link: http://lkml.kernel.org/r/20181214074330.18917-1-bpoirier@suse.com Signed-off-by:Benjamin Poirier <bpoirier@suse.com> Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Pavel Tatashin <pavel.tatashin@microsoft.com...
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