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mm/page_alloc.c: allow error injection

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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.

[[email protected]: changelog addition]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Benjamin Poirier <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Pavel Tatashin <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Joonsoo Kim <[email protected]>
Cc: Alexander Duyck <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Benjamin Poirier 2018-12-28 00:39:23 -08:00 • committed by Linus Torvalds
commit af3b854492
2 changed files with 9 additions and 2 deletions
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10
mm/page_alloc.c
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@ -3131,7 +3131,7 @@ static int __init setup_fail_page_alloc(char *str)
}
__setup("fail_page_alloc=", setup_fail_page_alloc);
static bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
static bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
if (order < fail_page_alloc.min_order)
return false;
@ -3181,13 +3181,19 @@ late_initcall(fail_page_alloc_debugfs);
#else /* CONFIG_FAIL_PAGE_ALLOC */
static inline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
static inline bool __should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
return false;
}
#endif /* CONFIG_FAIL_PAGE_ALLOC */
static noinline bool should_fail_alloc_page(gfp_t gfp_mask, unsigned int order)
{
return __should_fail_alloc_page(gfp_mask, order);
}
ALLOW_ERROR_INJECTION(should_fail_alloc_page, TRUE);
/*
* Return true if free base pages are above 'mark'. For high-order checks it
* will return true of the order-0 watermark is reached and there is at least