[PATCH 04/43] staging/lustre: Reintroduce global env list

From: green
Date: Wed Mar 30 2016 - 12:48:51 EST


From: Jinshan Xiong <jinshan.xiong@xxxxxxxxx>

This reverts a patch that was merged before lustre client
was introduced into the staging tree, so it's not in the history.

The performance dropped a lot when memory reclaim process kicked
in as ll_releasepage() was called to destroy lustre pages. It turned
out that big overhead to allocate cl_env and keys on the fly so we
have to revert this patch.

The original problem for the reverted patch would be solved in a
follow on patch instead.

Signed-off-by: Jinshan Xiong <jinshan.xiong@xxxxxxxxx>
Reviewed-on: http://review.whamcloud.com/7888
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3321
Reviewed-by: Niu Yawei <yawei.niu@xxxxxxxxx>
Reviewed-by: Lai Siyao <lai.siyao@xxxxxxxxx>
Signed-off-by: Oleg Drokin <green@xxxxxxxxxxxxxx>
---
drivers/staging/lustre/lustre/include/cl_object.h | 1 +
drivers/staging/lustre/lustre/llite/lcommon_misc.c | 3 +-
drivers/staging/lustre/lustre/llite/llite_lib.c | 2 +
drivers/staging/lustre/lustre/obdclass/cl_object.c | 90 ++++++++++++++++++++--
drivers/staging/lustre/lustre/obdclass/lu_object.c | 2 +
5 files changed, 92 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/lustre/lustre/include/cl_object.h b/drivers/staging/lustre/lustre/include/cl_object.h
index fb971de..e611f79 100644
--- a/drivers/staging/lustre/lustre/include/cl_object.h
+++ b/drivers/staging/lustre/lustre/include/cl_object.h
@@ -3241,6 +3241,7 @@ void *cl_env_reenter(void);
void cl_env_reexit(void *cookie);
void cl_env_implant(struct lu_env *env, int *refcheck);
void cl_env_unplant(struct lu_env *env, int *refcheck);
+unsigned int cl_env_cache_purge(unsigned int nr);

/** @} cl_env */

diff --git a/drivers/staging/lustre/lustre/llite/lcommon_misc.c b/drivers/staging/lustre/lustre/llite/lcommon_misc.c
index d80bcedd..f68c368 100644
--- a/drivers/staging/lustre/lustre/llite/lcommon_misc.c
+++ b/drivers/staging/lustre/lustre/llite/lcommon_misc.c
@@ -146,10 +146,11 @@ int cl_get_grouplock(struct cl_object *obj, unsigned long gid, int nonblock,

rc = cl_io_init(env, io, CIT_MISC, io->ci_obj);
if (rc) {
+ cl_io_fini(env, io);
+ cl_env_put(env, &refcheck);
/* Does not make sense to take GL for released layout */
if (rc > 0)
rc = -ENOTSUPP;
- cl_env_put(env, &refcheck);
return rc;
}

diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c
index 6d6bb33..673d31e 100644
--- a/drivers/staging/lustre/lustre/llite/llite_lib.c
+++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
@@ -999,6 +999,8 @@ void ll_put_super(struct super_block *sb)

lustre_common_put_super(sb);

+ cl_env_cache_purge(~0);
+
module_put(THIS_MODULE);
} /* client_put_super */

diff --git a/drivers/staging/lustre/lustre/obdclass/cl_object.c b/drivers/staging/lustre/lustre/obdclass/cl_object.c
index 43e299d..0772706 100644
--- a/drivers/staging/lustre/lustre/obdclass/cl_object.c
+++ b/drivers/staging/lustre/lustre/obdclass/cl_object.c
@@ -492,6 +492,13 @@ EXPORT_SYMBOL(cl_site_stats_print);
* 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;
@@ -697,6 +704,39 @@ static void cl_env_fini(struct cl_env *cle)
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);
@@ -727,6 +767,8 @@ static struct lu_env *cl_env_peek(int *refcheck)
* 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
@@ -740,10 +782,7 @@ struct lu_env *cl_env_get(int *refcheck)

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;

@@ -787,6 +826,32 @@ static void cl_env_exit(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
@@ -808,7 +873,22 @@ void cl_env_put(struct lu_env *env, int *refcheck)
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);
diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers/staging/lustre/lustre/obdclass/lu_object.c
index 69fdcee..770d5bd 100644
--- a/drivers/staging/lustre/lustre/obdclass/lu_object.c
+++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c
@@ -55,6 +55,7 @@
#include "../include/lustre_disk.h"
#include "../include/lustre_fid.h"
#include "../include/lu_object.h"
+#include "../include/cl_object.h"
#include "../include/lu_ref.h"
#include <linux/list.h>

@@ -1468,6 +1469,7 @@ void lu_context_key_quiesce(struct lu_context_key *key)
/*
* XXX layering violation.
*/
+ cl_env_cache_purge(~0);
key->lct_tags |= LCT_QUIESCENT;
/*
* XXX memory barrier has to go here.
--
2.1.0