#include "linux-kmem.h" /* * Memory allocation interfaces */ #ifdef DEBUG_KMEM /* Shim layer memory accounting */ atomic_t kmem_alloc_used; unsigned int kmem_alloc_max; #endif /* * Slab allocation interfaces * * While the linux slab implementation was inspired by solaris they * have made some changes to the API which complicates this shim * layer. For one thing the same symbol names are used with different * arguments for the prototypes. To deal with this we must use the * preprocessor to re-order arguments. Happily for us standard C says, * "Macro's appearing in their own expansion are not reexpanded" so * this does not result in an infinite recursion. Additionally the * function pointers registered by solarias differ from those used * by linux so a lookup and mapping from linux style callback to a * solaris style callback is needed. There is some overhead in this * operation which isn't horibile but it needs to be kept in mind. */ typedef struct kmem_cache_cb { struct list_head kcc_list; kmem_cache_t * kcc_cache; kmem_constructor_t kcc_constructor; kmem_destructor_t kcc_destructor; kmem_reclaim_t kcc_reclaim; void * kcc_private; void * kcc_vmp; } kmem_cache_cb_t; static spinlock_t kmem_cache_cb_lock = SPIN_LOCK_UNLOCKED; //static spinlock_t kmem_cache_cb_lock = (spinlock_t) { 1 SPINLOCK_MAGIC_INIT }; static LIST_HEAD(kmem_cache_cb_list); static struct shrinker *kmem_cache_shrinker; /* Function must be called while holding the kmem_cache_cb_lock * Because kmem_cache_t is an opaque datatype we're forced to * match pointers to identify specific cache entires. */ static kmem_cache_cb_t * kmem_cache_find_cache_cb(kmem_cache_t *cache) { kmem_cache_cb_t *kcc; list_for_each_entry(kcc, &kmem_cache_cb_list, kcc_list) if (cache == kcc->kcc_cache) return kcc; return NULL; } static kmem_cache_cb_t * kmem_cache_add_cache_cb(kmem_cache_t *cache, kmem_constructor_t constructor, kmem_destructor_t destructor, kmem_reclaim_t reclaim, void *priv, void *vmp) { kmem_cache_cb_t *kcc; kcc = (kmem_cache_cb_t *)kmalloc(sizeof(*kcc), GFP_KERNEL); if (kcc) { kcc->kcc_cache = cache; kcc->kcc_constructor = constructor; kcc->kcc_destructor = destructor; kcc->kcc_reclaim = reclaim; kcc->kcc_private = priv; kcc->kcc_vmp = vmp; spin_lock(&kmem_cache_cb_lock); list_add(&kcc->kcc_list, &kmem_cache_cb_list); spin_unlock(&kmem_cache_cb_lock); } return kcc; } static void kmem_cache_remove_cache_cb(kmem_cache_cb_t *kcc) { spin_lock(&kmem_cache_cb_lock); list_del(&kcc->kcc_list); spin_unlock(&kmem_cache_cb_lock); if (kcc) kfree(kcc); } static void kmem_cache_generic_constructor(void *ptr, kmem_cache_t *cache, unsigned long flags) { kmem_cache_cb_t *kcc; spin_lock(&kmem_cache_cb_lock); /* Callback list must be in sync with linux slab caches */ kcc = kmem_cache_find_cache_cb(cache); BUG_ON(!kcc); kcc->kcc_constructor(ptr, kcc->kcc_private, (int)flags); spin_unlock(&kmem_cache_cb_lock); /* Linux constructor has no return code, silently eat it */ } static void kmem_cache_generic_destructor(void *ptr, kmem_cache_t *cache, unsigned long flags) { kmem_cache_cb_t *kcc; spin_lock(&kmem_cache_cb_lock); /* Callback list must be in sync with linux slab caches */ kcc = kmem_cache_find_cache_cb(cache); BUG_ON(!kcc); /* Solaris destructor takes no flags, silently eat them */ kcc->kcc_destructor(ptr, kcc->kcc_private); spin_unlock(&kmem_cache_cb_lock); } /* XXX - Arguments are ignored */ static int kmem_cache_generic_shrinker(int nr_to_scan, unsigned int gfp_mask) { kmem_cache_cb_t *kcc; int total = 0; /* Under linux a shrinker is not tightly coupled with a slab * cache. In fact linux always systematically trys calling all * registered shrinker callbacks until its target reclamation level * is reached. Because of this we only register one shrinker * function in the shim layer for all slab caches. And we always * attempt to shrink all caches when this generic shrinker is called. */ spin_lock(&kmem_cache_cb_lock); list_for_each_entry(kcc, &kmem_cache_cb_list, kcc_list) { /* Under linux the desired number and gfp type of objects * is passed to the reclaiming function as a sugested reclaim * target. I do not pass these args on because reclaim * policy is entirely up to the owner under solaris. We only * pass on the pre-registered private data. */ if (kcc->kcc_reclaim) kcc->kcc_reclaim(kcc->kcc_private); total += 1; } /* Under linux we should return the remaining number of entires in * the cache. Unfortunately, I don't see an easy way to safely * emulate this behavior so I'm returning one entry per cache which * was registered with the generic shrinker. This should fake out * the linux VM when it attempts to shrink caches. */ spin_unlock(&kmem_cache_cb_lock); return total; } /* Ensure the __kmem_cache_create/__kmem_cache_destroy macros are * removed here to prevent a recursive substitution, we want to call * the native linux version. */ #undef kmem_cache_create #undef kmem_cache_destroy kmem_cache_t * __kmem_cache_create(char *name, size_t size, size_t align, kmem_constructor_t constructor, kmem_destructor_t destructor, kmem_reclaim_t reclaim, void *priv, void *vmp, int flags) { kmem_cache_t *cache; kmem_cache_cb_t *kcc; int shrinker_flag = 0; /* FIXME: - Option currently unsupported by shim layer */ BUG_ON(vmp); cache = kmem_cache_create(name, size, align, flags, kmem_cache_generic_constructor, kmem_cache_generic_destructor); if (cache == NULL) return NULL; /* Register shared shrinker function on initial cache create */ spin_lock(&kmem_cache_cb_lock); if (list_empty(&kmem_cache_cb_list)) { kmem_cache_shrinker = set_shrinker(KMC_DEFAULT_SEEKS, kmem_cache_generic_shrinker); if (kmem_cache_shrinker == NULL) { kmem_cache_destroy(cache); spin_unlock(&kmem_cache_cb_lock); return NULL; } } spin_unlock(&kmem_cache_cb_lock); kcc = kmem_cache_add_cache_cb(cache, constructor, destructor, reclaim, priv, vmp); if (kcc == NULL) { if (shrinker_flag) /* New shrinker registered must be removed */ remove_shrinker(kmem_cache_shrinker); kmem_cache_destroy(cache); return NULL; } return cache; } EXPORT_SYMBOL(__kmem_cache_create); /* Return codes discarded because Solaris implementation has void return */ void __kmem_cache_destroy(kmem_cache_t *cache) { kmem_cache_cb_t *kcc; spin_lock(&kmem_cache_cb_lock); kcc = kmem_cache_find_cache_cb(cache); spin_unlock(&kmem_cache_cb_lock); if (kcc == NULL) return; kmem_cache_destroy(cache); kmem_cache_remove_cache_cb(kcc); /* Unregister generic shrinker on removal of all caches */ spin_lock(&kmem_cache_cb_lock); if (list_empty(&kmem_cache_cb_list)) remove_shrinker(kmem_cache_shrinker); spin_unlock(&kmem_cache_cb_lock); } EXPORT_SYMBOL(__kmem_cache_destroy); void __kmem_reap(void) { /* Since there's no easy hook in to linux to force all the registered * shrinkers to run we just run the ones registered for this shim */ kmem_cache_generic_shrinker(KMC_REAP_CHUNK, GFP_KERNEL); } EXPORT_SYMBOL(__kmem_reap);