* [PATCH] mm/page_alloc.c: Allow error injection
@ 2018-12-14 7:43 Benjamin Poirier
2018-12-14 7:43 ` Benjamin Poirier
2018-12-14 14:24 ` Vlastimil Babka
0 siblings, 2 replies; 4+ messages in thread
From: Benjamin Poirier @ 2018-12-14 7:43 UTC (permalink / raw)
To: linux-mm
Cc: Arnd Bergmann, Andrew Morton, Michal Hocko, Pavel Tatashin,
Vlastimil Babka, Oscar Salvador, Mike Rapoport, Joonsoo Kim,
Alexander Duyck, linux-arch, linux-kernel
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*().
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
---
include/asm-generic/error-injection.h | 1 +
mm/page_alloc.c | 10 ++++++++--
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h
index 296c65442f00..95a159a4137f 100644
--- a/include/asm-generic/error-injection.h
+++ b/include/asm-generic/error-injection.h
@@ -8,6 +8,7 @@ enum {
EI_ETYPE_NULL, /* Return NULL if failure */
EI_ETYPE_ERRNO, /* Return -ERRNO if failure */
EI_ETYPE_ERRNO_NULL, /* Return -ERRNO or NULL if failure */
+ EI_ETYPE_TRUE, /* Return true if failure */
};
struct error_injection_entry {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2ec9cc407216..64861d79dc2d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3053,7 +3053,7 @@ 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;
@@ -3103,13 +3103,19 @@ 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
--
2.19.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH] mm/page_alloc.c: Allow error injection
2018-12-14 7:43 [PATCH] mm/page_alloc.c: Allow error injection Benjamin Poirier
@ 2018-12-14 7:43 ` Benjamin Poirier
2018-12-14 14:24 ` Vlastimil Babka
1 sibling, 0 replies; 4+ messages in thread
From: Benjamin Poirier @ 2018-12-14 7:43 UTC (permalink / raw)
To: linux-mm
Cc: Arnd Bergmann, Andrew Morton, Michal Hocko, Pavel Tatashin,
Vlastimil Babka, Oscar Salvador, Mike Rapoport, Joonsoo Kim,
Alexander Duyck, linux-arch, linux-kernel
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*().
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
---
include/asm-generic/error-injection.h | 1 +
mm/page_alloc.c | 10 ++++++++--
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h
index 296c65442f00..95a159a4137f 100644
--- a/include/asm-generic/error-injection.h
+++ b/include/asm-generic/error-injection.h
@@ -8,6 +8,7 @@ enum {
EI_ETYPE_NULL, /* Return NULL if failure */
EI_ETYPE_ERRNO, /* Return -ERRNO if failure */
EI_ETYPE_ERRNO_NULL, /* Return -ERRNO or NULL if failure */
+ EI_ETYPE_TRUE, /* Return true if failure */
};
struct error_injection_entry {
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2ec9cc407216..64861d79dc2d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3053,7 +3053,7 @@ 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;
@@ -3103,13 +3103,19 @@ 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
--
2.19.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] mm/page_alloc.c: Allow error injection
2018-12-14 7:43 [PATCH] mm/page_alloc.c: Allow error injection Benjamin Poirier
2018-12-14 7:43 ` Benjamin Poirier
@ 2018-12-14 14:24 ` Vlastimil Babka
2018-12-14 14:24 ` Vlastimil Babka
1 sibling, 1 reply; 4+ messages in thread
From: Vlastimil Babka @ 2018-12-14 14:24 UTC (permalink / raw)
To: Benjamin Poirier, linux-mm
Cc: Arnd Bergmann, Andrew Morton, Michal Hocko, Pavel Tatashin,
Oscar Salvador, Mike Rapoport, Joonsoo Kim, Alexander Duyck,
linux-arch, linux-kernel, Mel Gorman, Nicolas Saenz Julienne
On 12/14/18 8:43 AM, Benjamin Poirier wrote:
> 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*().
I'd be more explicit about both the advantages and disadvantages, as we
discussed internally. E.g. something along:
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.
> Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
> ---
> include/asm-generic/error-injection.h | 1 +
> mm/page_alloc.c | 10 ++++++++--
> 2 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h
> index 296c65442f00..95a159a4137f 100644
> --- a/include/asm-generic/error-injection.h
> +++ b/include/asm-generic/error-injection.h
> @@ -8,6 +8,7 @@ enum {
> EI_ETYPE_NULL, /* Return NULL if failure */
> EI_ETYPE_ERRNO, /* Return -ERRNO if failure */
> EI_ETYPE_ERRNO_NULL, /* Return -ERRNO or NULL if failure */
> + EI_ETYPE_TRUE, /* Return true if failure */
> };
>
> struct error_injection_entry {
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 2ec9cc407216..64861d79dc2d 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -3053,7 +3053,7 @@ 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;
> @@ -3103,13 +3103,19 @@ 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
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] mm/page_alloc.c: Allow error injection
2018-12-14 14:24 ` Vlastimil Babka
@ 2018-12-14 14:24 ` Vlastimil Babka
0 siblings, 0 replies; 4+ messages in thread
From: Vlastimil Babka @ 2018-12-14 14:24 UTC (permalink / raw)
To: Benjamin Poirier, linux-mm
Cc: Arnd Bergmann, Andrew Morton, Michal Hocko, Pavel Tatashin,
Oscar Salvador, Mike Rapoport, Joonsoo Kim, Alexander Duyck,
linux-arch, linux-kernel, Mel Gorman, Nicolas Saenz Julienne
On 12/14/18 8:43 AM, Benjamin Poirier wrote:
> 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*().
I'd be more explicit about both the advantages and disadvantages, as we
discussed internally. E.g. something along:
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.
> Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
> ---
> include/asm-generic/error-injection.h | 1 +
> mm/page_alloc.c | 10 ++++++++--
> 2 files changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h
> index 296c65442f00..95a159a4137f 100644
> --- a/include/asm-generic/error-injection.h
> +++ b/include/asm-generic/error-injection.h
> @@ -8,6 +8,7 @@ enum {
> EI_ETYPE_NULL, /* Return NULL if failure */
> EI_ETYPE_ERRNO, /* Return -ERRNO if failure */
> EI_ETYPE_ERRNO_NULL, /* Return -ERRNO or NULL if failure */
> + EI_ETYPE_TRUE, /* Return true if failure */
> };
>
> struct error_injection_entry {
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 2ec9cc407216..64861d79dc2d 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -3053,7 +3053,7 @@ 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;
> @@ -3103,13 +3103,19 @@ 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
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2018-12-14 7:43 [PATCH] mm/page_alloc.c: Allow error injection Benjamin Poirier
2018-12-14 7:43 ` Benjamin Poirier
2018-12-14 14:24 ` Vlastimil Babka
2018-12-14 14:24 ` Vlastimil Babka
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