From 8a8b6502fb669c3a0638a08955442814cedc86b1 Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Fri, 8 Dec 2006 02:39:44 -0800 Subject: [PATCH] fault-injection capability for kmalloc This patch provides fault-injection capability for kmalloc. Boot option: failslab=,,, -- specifies the interval of failures. -- specifies how often it should fail in percent. -- specifies the size of free space where memory can be allocated safely in bytes. -- specifies how many times failures may happen at most. Debugfs: /debug/failslab/interval /debug/failslab/probability /debug/failslab/specifies /debug/failslab/times /debug/failslab/ignore-gfp-highmem /debug/failslab/ignore-gfp-wait Example: failslab=10,100,0,-1 slab allocation (kmalloc(), kmem_cache_alloc(),..) fails once per 10 times. Cc: Pekka Enberg Signed-off-by: Akinobu Mita Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) (limited to 'mm/slab.c') diff --git a/mm/slab.c b/mm/slab.c index e90b6100a927..47011e2ef3c9 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -107,6 +107,7 @@ #include #include #include +#include #include #include @@ -3088,12 +3089,88 @@ static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, #define cache_alloc_debugcheck_after(a,b,objp,d) (objp) #endif +#ifdef CONFIG_FAILSLAB + +static struct failslab_attr { + + struct fault_attr attr; + + u32 ignore_gfp_wait; +#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS + struct dentry *ignore_gfp_wait_file; +#endif + +} failslab = { + .attr = FAULT_ATTR_INITIALIZER, +}; + +static int __init setup_failslab(char *str) +{ + return setup_fault_attr(&failslab.attr, str); +} +__setup("failslab=", setup_failslab); + +static int should_failslab(struct kmem_cache *cachep, gfp_t flags) +{ + if (cachep == &cache_cache) + return 0; + if (flags & __GFP_NOFAIL) + return 0; + if (failslab.ignore_gfp_wait && (flags & __GFP_WAIT)) + return 0; + + return should_fail(&failslab.attr, obj_size(cachep)); +} + +#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS + +static int __init failslab_debugfs(void) +{ + mode_t mode = S_IFREG | S_IRUSR | S_IWUSR; + struct dentry *dir; + int err; + + err = init_fault_attr_dentries(&failslab.attr, "failslab"); + if (err) + return err; + dir = failslab.attr.dentries.dir; + + failslab.ignore_gfp_wait_file = + debugfs_create_bool("ignore-gfp-wait", mode, dir, + &failslab.ignore_gfp_wait); + + if (!failslab.ignore_gfp_wait_file) { + err = -ENOMEM; + debugfs_remove(failslab.ignore_gfp_wait_file); + cleanup_fault_attr_dentries(&failslab.attr); + } + + return err; +} + +late_initcall(failslab_debugfs); + +#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */ + +#else /* CONFIG_FAILSLAB */ + +static inline int should_failslab(struct kmem_cache *cachep, gfp_t flags) +{ + return 0; +} + +#endif /* CONFIG_FAILSLAB */ + static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) { void *objp; struct array_cache *ac; check_irq_off(); + + if (should_failslab(cachep, flags)) + return NULL; + ac = cpu_cache_get(cachep); if (likely(ac->avail)) { STATS_INC_ALLOCHIT(cachep); -- cgit v1.2.3