From: Jinshan Xiong <jinshan.xiong@xxxxxxxxx> This change adds support for a single preallocated cl_env per CPU which can be used in circumstances where reschedule is not possible. Currently this interface is only used by the ll_releasepage function. Signed-off-by: Jinshan Xiong <jinshan.xiong@xxxxxxxxx> Signed-off-by: Prakash Surya <surya1@xxxxxxxx> Reviewed-on: http://review.whamcloud.com/8174 Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3321 Reviewed-by: Lai Siyao <lai.siyao@xxxxxxxxx> Reviewed-by: Bobi Jam <bobijam@xxxxxxxxx> Signed-off-by: Oleg Drokin <green@xxxxxxxxxxxxxx> --- drivers/staging/lustre/lustre/include/cl_object.h | 12 +++ drivers/staging/lustre/lustre/llite/rw26.c | 54 +++++++---- drivers/staging/lustre/lustre/obdclass/cl_lock.c | 1 - drivers/staging/lustre/lustre/obdclass/cl_object.c | 107 +++++++++++++++++++++ drivers/staging/lustre/lustre/obdclass/cl_page.c | 1 - 5 files changed, 152 insertions(+), 23 deletions(-) diff --git a/drivers/staging/lustre/lustre/include/cl_object.h b/drivers/staging/lustre/lustre/include/cl_object.h index 5daf688..e8455dc 100644 --- a/drivers/staging/lustre/lustre/include/cl_object.h +++ b/drivers/staging/lustre/lustre/include/cl_object.h @@ -2773,6 +2773,16 @@ static inline void *cl_object_page_slice(struct cl_object *clob, return (void *)((char *)page + clob->co_slice_off); } +/** + * Return refcount of cl_object. + */ +static inline int cl_object_refc(struct cl_object *clob) +{ + struct lu_object_header *header = clob->co_lu.lo_header; + + return atomic_read(&header->loh_ref); +} + /** @} cl_object */ /** \defgroup cl_page cl_page @@ -3226,6 +3236,8 @@ 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); +struct lu_env *cl_env_percpu_get(void); +void cl_env_percpu_put(struct lu_env *env); /** @} cl_env */ diff --git a/drivers/staging/lustre/lustre/llite/rw26.c b/drivers/staging/lustre/lustre/llite/rw26.c index b5335de..cc49c21 100644 --- a/drivers/staging/lustre/lustre/llite/rw26.c +++ b/drivers/staging/lustre/lustre/llite/rw26.c @@ -107,12 +107,12 @@ static void ll_invalidatepage(struct page *vmpage, unsigned int offset, static int ll_releasepage(struct page *vmpage, gfp_t gfp_mask) { - struct cl_env_nest nest; struct lu_env *env; + void *cookie; struct cl_object *obj; struct cl_page *page; struct address_space *mapping; - int result; + int result = 0; LASSERT(PageLocked(vmpage)); if (PageWriteback(vmpage) || PageDirty(vmpage)) @@ -126,30 +126,42 @@ static int ll_releasepage(struct page *vmpage, gfp_t gfp_mask) if (!obj) return 1; - /* 1 for page allocator, 1 for cl_page and 1 for page cache */ + /* 1 for caller, 1 for cl_page and 1 for page cache */ if (page_count(vmpage) > 3) return 0; - /* TODO: determine what gfp should be used by @gfp_mask. */ - env = cl_env_nested_get(&nest); - if (IS_ERR(env)) - /* If we can't allocate an env we won't call cl_page_put() - * later on which further means it's impossible to drop - * page refcount by cl_page, so ask kernel to not free - * this page. - */ - return 0; - page = cl_vmpage_page(vmpage, obj); - result = !page; - if (page) { - if (!cl_page_in_use(page)) { - result = 1; - cl_page_delete(env, page); - } - cl_page_put(env, page); + if (!page) + return 1; + + cookie = cl_env_reenter(); + env = cl_env_percpu_get(); + LASSERT(!IS_ERR(env)); + + if (!cl_page_in_use(page)) { + result = 1; + cl_page_delete(env, page); } - cl_env_nested_put(&nest, env); + + /* To use percpu env array, the call path can not be rescheduled; + * otherwise percpu array will be messed if ll_releaspage() called + * again on the same CPU. + * + * If this page holds the last refc of cl_object, the following + * call path may cause reschedule: + * cl_page_put -> cl_page_free -> cl_object_put -> + * lu_object_put -> lu_object_free -> lov_delete_raid0 -> + * cl_locks_prune. + * + * However, the kernel can't get rid of this inode until all pages have + * been cleaned up. Now that we hold page lock here, it's pretty safe + * that we won't get into object delete path. + */ + LASSERT(cl_object_refc(obj) > 1); + cl_page_put(env, page); + + cl_env_percpu_put(env); + cl_env_reexit(cookie); return result; } diff --git a/drivers/staging/lustre/lustre/obdclass/cl_lock.c b/drivers/staging/lustre/lustre/obdclass/cl_lock.c index 32ecc5a..fe8059a 100644 --- a/drivers/staging/lustre/lustre/obdclass/cl_lock.c +++ b/drivers/staging/lustre/lustre/obdclass/cl_lock.c @@ -255,7 +255,6 @@ static void cl_lock_free(const struct lu_env *env, struct cl_lock *lock) LINVRNT(!cl_lock_is_mutexed(lock)); cl_lock_trace(D_DLMTRACE, env, "free lock", lock); - might_sleep(); while (!list_empty(&lock->cll_layers)) { struct cl_lock_slice *slice; diff --git a/drivers/staging/lustre/lustre/obdclass/cl_object.c b/drivers/staging/lustre/lustre/obdclass/cl_object.c index 65b6402..fa9b083 100644 --- a/drivers/staging/lustre/lustre/obdclass/cl_object.c +++ b/drivers/staging/lustre/lustre/obdclass/cl_object.c @@ -390,6 +390,8 @@ static int cache_stats_print(const struct cache_stats *cs, return 0; } +static void cl_env_percpu_refill(void); + /** * Initialize client site. * @@ -409,6 +411,7 @@ int cl_site_init(struct cl_site *s, struct cl_device *d) atomic_set(&s->cs_pages_state[0], 0); for (i = 0; i < ARRAY_SIZE(s->cs_locks_state); ++i) atomic_set(&s->cs_locks_state[i], 0); + cl_env_percpu_refill(); } return result; } @@ -1001,6 +1004,104 @@ void cl_lvb2attr(struct cl_attr *attr, const struct ost_lvb *lvb) } EXPORT_SYMBOL(cl_lvb2attr); +static struct cl_env cl_env_percpu[NR_CPUS]; + +static int cl_env_percpu_init(void) +{ + struct cl_env *cle; + int tags = LCT_REMEMBER | LCT_NOREF; + int i, j; + int rc = 0; + + for_each_possible_cpu(i) { + struct lu_env *env; + + cle = &cl_env_percpu[i]; + env = &cle->ce_lu; + + INIT_LIST_HEAD(&cle->ce_linkage); + cle->ce_magic = &cl_env_init0; + rc = lu_env_init(env, LCT_CL_THREAD | tags); + if (rc == 0) { + rc = lu_context_init(&cle->ce_ses, LCT_SESSION | tags); + if (rc == 0) { + lu_context_enter(&cle->ce_ses); + env->le_ses = &cle->ce_ses; + } else { + lu_env_fini(env); + } + } + if (rc != 0) + break; + } + if (rc != 0) { + /* Indices 0 to i (excluding i) were correctly initialized, + * thus we must uninitialize up to i, the rest are undefined. + */ + for (j = 0; j < i; j++) { + cle = &cl_env_percpu[i]; + lu_context_exit(&cle->ce_ses); + lu_context_fini(&cle->ce_ses); + lu_env_fini(&cle->ce_lu); + } + } + + return rc; +} + +static void cl_env_percpu_fini(void) +{ + int i; + + for_each_possible_cpu(i) { + struct cl_env *cle = &cl_env_percpu[i]; + + lu_context_exit(&cle->ce_ses); + lu_context_fini(&cle->ce_ses); + lu_env_fini(&cle->ce_lu); + } +} + +static void cl_env_percpu_refill(void) +{ + int i; + + for_each_possible_cpu(i) + lu_env_refill(&cl_env_percpu[i].ce_lu); +} + +void cl_env_percpu_put(struct lu_env *env) +{ + struct cl_env *cle; + int cpu; + + cpu = smp_processor_id(); + cle = cl_env_container(env); + LASSERT(cle == &cl_env_percpu[cpu]); + + cle->ce_ref--; + LASSERT(cle->ce_ref == 0); + + CL_ENV_DEC(busy); + cl_env_detach(cle); + cle->ce_debug = NULL; + + put_cpu(); +} +EXPORT_SYMBOL(cl_env_percpu_put); + +struct lu_env *cl_env_percpu_get() +{ + struct cl_env *cle; + + cle = &cl_env_percpu[get_cpu()]; + cl_env_init0(cle, __builtin_return_address(0)); + + cl_env_attach(cle); + return &cle->ce_lu; +} +EXPORT_SYMBOL(cl_env_percpu_get); + /***************************************************************************** * * Temporary prototype thing: mirror obd-devices into cl devices. @@ -1154,6 +1255,11 @@ int cl_global_init(void) if (result) goto out_lock; + result = cl_env_percpu_init(); + if (result) + /* no cl_env_percpu_fini on error */ + goto out_lock; + return 0; out_lock: cl_lock_fini(); @@ -1171,6 +1277,7 @@ out_store: */ void cl_global_fini(void) { + cl_env_percpu_fini(); cl_lock_fini(); cl_page_fini(); lu_context_key_degister(&cl_key); diff --git a/drivers/staging/lustre/lustre/obdclass/cl_page.c b/drivers/staging/lustre/lustre/obdclass/cl_page.c index 8169836..bab8a74 100644 --- a/drivers/staging/lustre/lustre/obdclass/cl_page.c +++ b/drivers/staging/lustre/lustre/obdclass/cl_page.c @@ -123,7 +123,6 @@ static void cl_page_free(const struct lu_env *env, struct cl_page *page) PASSERT(env, page, !page->cp_parent); PASSERT(env, page, page->cp_state == CPS_FREEING); - might_sleep(); while (!list_empty(&page->cp_layers)) { struct cl_page_slice *slice; -- 2.1.0 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
