* bz20044, bz22683.
*/
+static LIST_HEAD(cl_envs);
+static unsigned int cl_envs_cached_nr;
+static unsigned int cl_envs_cached_max = 128; /* XXX: prototype: arbitrary limit
+ * for now.
+ */
+static DEFINE_SPINLOCK(cl_envs_guard);
+
struct cl_env {
void *ce_magic;
struct lu_env ce_lu;
kmem_cache_free(cl_env_kmem, cle);
}
+static struct lu_env *cl_env_obtain(void *debug)
+{
+ struct cl_env *cle;
+ struct lu_env *env;
+
+ spin_lock(&cl_envs_guard);
+ LASSERT(equi(cl_envs_cached_nr == 0, list_empty(&cl_envs)));
+ if (cl_envs_cached_nr > 0) {
+ int rc;
+
+ cle = container_of(cl_envs.next, struct cl_env, ce_linkage);
+ list_del_init(&cle->ce_linkage);
+ cl_envs_cached_nr--;
+ spin_unlock(&cl_envs_guard);
+
+ env = &cle->ce_lu;
+ rc = lu_env_refill(env);
+ if (rc == 0) {
+ cl_env_init0(cle, debug);
+ lu_context_enter(&env->le_ctx);
+ lu_context_enter(&cle->ce_ses);
+ } else {
+ cl_env_fini(cle);
+ env = ERR_PTR(rc);
+ }
+ } else {
+ spin_unlock(&cl_envs_guard);
+ env = cl_env_new(lu_context_tags_default,
+ lu_session_tags_default, debug);
+ }
+ return env;
+}
+
static inline struct cl_env *cl_env_container(struct lu_env *env)
{
return container_of(env, struct cl_env, ce_lu);
* Returns lu_env: if there already is an environment associated with the
* current thread, it is returned, otherwise, new environment is allocated.
*
+ * Allocations are amortized through the global cache of environments.
+ *
* \param refcheck pointer to a counter used to detect environment leaks. In
* the usual case cl_env_get() and cl_env_put() are called in the same lexical
* scope and pointer to the same integer is passed as \a refcheck. This is
env = cl_env_peek(refcheck);
if (!env) {
- env = cl_env_new(lu_context_tags_default,
- lu_session_tags_default,
- __builtin_return_address(0));
-
+ env = cl_env_obtain(__builtin_return_address(0));
if (!IS_ERR(env)) {
struct cl_env *cle;
}
/**
+ * Finalizes and frees a given number of cached environments. This is done to
+ * (1) free some memory (not currently hooked into VM), or (2) release
+ * references to modules.
+ */
+unsigned int cl_env_cache_purge(unsigned int nr)
+{
+ struct cl_env *cle;
+
+ spin_lock(&cl_envs_guard);
+ for (; !list_empty(&cl_envs) && nr > 0; --nr) {
+ cle = container_of(cl_envs.next, struct cl_env, ce_linkage);
+ list_del_init(&cle->ce_linkage);
+ LASSERT(cl_envs_cached_nr > 0);
+ cl_envs_cached_nr--;
+ spin_unlock(&cl_envs_guard);
+
+ cl_env_fini(cle);
+ spin_lock(&cl_envs_guard);
+ }
+ LASSERT(equi(cl_envs_cached_nr == 0, list_empty(&cl_envs)));
+ spin_unlock(&cl_envs_guard);
+ return nr;
+}
+EXPORT_SYMBOL(cl_env_cache_purge);
+
+/**
* Release an environment.
*
* Decrement \a env reference counter. When counter drops to 0, nothing in
cl_env_detach(cle);
cle->ce_debug = NULL;
cl_env_exit(cle);
- cl_env_fini(cle);
+ /*
+ * Don't bother to take a lock here.
+ *
+ * Return environment to the cache only when it was allocated
+ * with the standard tags.
+ */
+ if (cl_envs_cached_nr < cl_envs_cached_max &&
+ (env->le_ctx.lc_tags & ~LCT_HAS_EXIT) == LCT_CL_THREAD &&
+ (env->le_ses->lc_tags & ~LCT_HAS_EXIT) == LCT_SESSION) {
+ spin_lock(&cl_envs_guard);
+ list_add(&cle->ce_linkage, &cl_envs);
+ cl_envs_cached_nr++;
+ spin_unlock(&cl_envs_guard);
+ } else {
+ cl_env_fini(cle);
+ }
}
}
EXPORT_SYMBOL(cl_env_put);