Messages in this thread | | | From | Dmitry Monakhov <> | Subject | Re: [PATCH] failslab: add ability to filter slab caches | Date | Thu, 25 Feb 2010 08:50:15 +0300 |
| |
David Rientjes <rientjes@google.com> writes:
> On Wed, 24 Feb 2010, Dmitry Monakhov wrote: > >> >> Example: >> >> echo 1 > /sys/kernel/slab/skbuff_head_cache/failslab >> >> echo 1 > /sys/kernel/debug/failslab/cache-filter >> >> >> > >> > Where's the changelog? >> I've hoped than subject is enough. But if you want more verbose >> changelog, take following version. >> Ohh... i'm sorry i've missed other comments in your previous review. It will be fixed in second version. Also see major note about slab flags later in the text. > > Please do not attach patches to emails when sending to LKML, they are > preferred to be inline. See Documentation/SubmittingPatches. Yeah, In fact i've chose inline option but my mailer by unknown reason change it. > >> This patch allow to inject faults only for specific slabs. >> In order to preserve default behavior cache filter is off by >> default (all caches are faulty). >> >> One may define specific set of slabs like this: >> # mark skbuff_head_cache as faulty >> echo 1 > /sys/kernel/slab/skbuff_head_cache/failslab >> # Turn on cache filter (off by default) >> echo 1 > /sys/kernel/debug/failslab/cache-filter >> # Turn on fault injection >> echo 1 > /sys/kernel/debug/failslab/times >> echo 1 > /sys/kernel/debug/failslab/probability >> > > Please describe your new slub_debug=a option here as well as in an update > to Documentation/vm/slub.txt. Done > >> Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> >> --- >> include/linux/fault-inject.h | 4 ++-- >> include/linux/slab.h | 4 +++- >> mm/failslab.c | 18 +++++++++++++++--- >> mm/slab.c | 2 +- >> mm/slub.c | 31 +++++++++++++++++++++++++++++-- >> 5 files changed, 50 insertions(+), 9 deletions(-) >> >> diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h >> index 06ca9b2..d935647 100644 >> --- a/include/linux/fault-inject.h >> +++ b/include/linux/fault-inject.h >> @@ -82,9 +82,9 @@ static inline void cleanup_fault_attr_dentries(struct fault_attr *attr) >> #endif /* CONFIG_FAULT_INJECTION */ >> >> #ifdef CONFIG_FAILSLAB >> -extern bool should_failslab(size_t size, gfp_t gfpflags); >> +extern bool should_failslab(size_t size, gfp_t gfpflags, unsigned long c_flags); >> #else >> -static inline bool should_failslab(size_t size, gfp_t gfpflags) >> +static inline bool should_failslab(size_t size, gfp_t gfpflags, unsigned long f) >> { >> return false; >> } > > As I said in the first review, these need to be more descriptive: 'flags' > would be better. done > >> diff --git a/include/linux/slab.h b/include/linux/slab.h >> index 2da8372..9e03a81 100644 >> --- a/include/linux/slab.h >> +++ b/include/linux/slab.h >> @@ -70,7 +70,9 @@ >> #else >> # define SLAB_NOTRACK 0x00000000UL >> #endif >> - >> +#ifdef CONFIG_FAILSLAB >> +# define SLAB_FAILSLAB 0x02000000UL /* Fault injection filter mark */ >> +#endif > > Trailing whitespace on your #endif. Sorry. fixed > >> /* The following flags affect the page allocator grouping pages by mobility */ >> #define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */ >> #define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */ >> diff --git a/mm/failslab.c b/mm/failslab.c >> index 9339de5..bb41f98 100644 >> --- a/mm/failslab.c >> +++ b/mm/failslab.c >> @@ -1,18 +1,22 @@ >> #include <linux/fault-inject.h> >> #include <linux/gfp.h> >> +#include <linux/slab.h> >> >> static struct { >> struct fault_attr attr; >> u32 ignore_gfp_wait; >> + int cache_filter; >> #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS >> struct dentry *ignore_gfp_wait_file; >> + struct dentry *cache_filter_file; >> #endif >> } failslab = { >> .attr = FAULT_ATTR_INITIALIZER, >> .ignore_gfp_wait = 1, >> + .cache_filter = 0, >> }; >> >> -bool should_failslab(size_t size, gfp_t gfpflags) >> +bool should_failslab(size_t size, gfp_t gfpflags, unsigned long cache_flags) >> { >> if (gfpflags & __GFP_NOFAIL) >> return false; >> @@ -20,6 +24,9 @@ bool should_failslab(size_t size, gfp_t gfpflags) >> if (failslab.ignore_gfp_wait && (gfpflags & __GFP_WAIT)) >> return false; >> >> + if (failslab.cache_filter && !(cache_flags & SLAB_FAILSLAB)) >> + return false; >> + >> return should_fail(&failslab.attr, size); >> } >> >> @@ -30,7 +37,6 @@ static int __init setup_failslab(char *str) >> __setup("failslab=", setup_failslab); >> >> #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS >> - >> static int __init failslab_debugfs_init(void) >> { >> mode_t mode = S_IFREG | S_IRUSR | S_IWUSR; >> @@ -46,8 +52,14 @@ static int __init failslab_debugfs_init(void) >> debugfs_create_bool("ignore-gfp-wait", mode, dir, >> &failslab.ignore_gfp_wait); >> >> - if (!failslab.ignore_gfp_wait_file) { >> + failslab.cache_filter_file = >> + debugfs_create_bool("cache-filter", mode, dir, >> + &failslab.cache_filter); >> + >> + if (!failslab.ignore_gfp_wait_file || >> + !failslab.cache_filter_file) { >> err = -ENOMEM; >> + debugfs_remove(failslab.cache_filter_file); >> debugfs_remove(failslab.ignore_gfp_wait_file); >> cleanup_fault_attr_dentries(&failslab.attr); >> } >> diff --git a/mm/slab.c b/mm/slab.c >> index 7451bda..33496b7 100644 >> --- a/mm/slab.c >> +++ b/mm/slab.c >> @@ -3101,7 +3101,7 @@ static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags) >> if (cachep == &cache_cache) >> return false; >> >> - return should_failslab(obj_size(cachep), flags); >> + return should_failslab(obj_size(cachep), flags, cachep->flags); >> } >> > > cachep->flags for CONFIG_SLAB is of type unsigned int and > should_failslab() takes an unsigned long. Strange story, seems that flag definition in slab_def.h is differ from slub_def.h and slob_def.h (unsigned long long) Need to be fixed. Will send as separate patch. > >> static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) >> diff --git a/mm/slub.c b/mm/slub.c >> index 8d71aaf..64114fa 100644 >> --- a/mm/slub.c >> +++ b/mm/slub.c >> @@ -151,7 +151,8 @@ >> * Set of flags that will prevent slab merging >> */ >> #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ >> - SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE) >> + SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \ >> + SLAB_FAILSLAB) >> >> #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \ >> SLAB_CACHE_DMA | SLAB_NOTRACK) > > As I mentioned in my first review of your patch, this breaks for > CONFIG_FAILSLAB=n. Please make sure your patch compiles for the > defconfig. fixed.
| |