staging/lustre/osc: some cleanup to reduce stack overflow chance

ptlrpcd_add_req() will wake_up other process, do not hold a spinlock
before calling ptlrpcd_queue_work()->ptlrpcd_add_req().

If current process is allocating memory, memory shrinker could get to
osc_lru_del(), don't call osc_lru_shrink() further since it could
lead a long calling chain.

Use static string OES_STRINGS in OSC_EXTENT_DUMP() to reduce stack
footprint.

Alloc crattr on heap for osc_build_rpc() to reduce stack footprint.

Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-3281
Lustre-change: http://review.whamcloud.com/6270Signed-off-by: NBobi Jam <bobijam.xu@intel.com>
Reviewed-by: NJinshan Xiong <jinshan.xiong@intel.com>
Reviewed-by: NKeith Mannthey <keith.mannthey@intel.com>
Reviewed-by: NAndreas Dilger <andreas.dilger@intel.com>
Signed-off-by: NPeng Tao <tao.peng@emc.com>
Signed-off-by: NAndreas Dilger <andreas.dilger@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/osc/osc_cache.c

@@ -99,10 +99,11 @@ static inline char list_empty_marker(struct list_head *list)
 
 #define EXTSTR       "[%lu -> %lu/%lu]"
 #define EXTPARA(ext) (ext)->oe_start, (ext)->oe_end, (ext)->oe_max_end
+static const char *oes_strings[] = {
+	"inv", "active", "cache", "locking", "lockdone", "rpc", "trunc", NULL };
 
 #define OSC_EXTENT_DUMP(lvl, extent, fmt, ...) do {			      \
 	struct osc_extent *__ext = (extent);				      \
-	const char *__str[] = OES_STRINGS;				      \
 	char __buf[16];							      \
 									      \
 	CDEBUG(lvl,							      \
@@ -114,7 +115,7 @@ static inline char list_empty_marker(struct list_head *list)
 		atomic_read(&__ext->oe_refc),			      \
 		atomic_read(&__ext->oe_users),			      \
 		list_empty_marker(&__ext->oe_link),			      \
-		__str[__ext->oe_state], ext_flags(__ext, __buf),	      \
+		oes_strings[__ext->oe_state], ext_flags(__ext, __buf),	      \
 		__ext->oe_obj,						      \
 		/* ----- part 2 ----- */				      \
 		__ext->oe_grants, __ext->oe_nr_pages,			      \
@@ -128,10 +129,10 @@ static inline char list_empty_marker(struct list_head *list)
 #undef EASSERTF
 #define EASSERTF(expr, ext, fmt, args...) do {				\
 	if (!(expr)) {							\
-		OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);		 \
-		osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);		 \
+		OSC_EXTENT_DUMP(D_ERROR, (ext), fmt, ##args);		\
+		osc_extent_tree_dump(D_ERROR, (ext)->oe_obj);		\
 		LASSERT(expr);						\
-	}								     \
+	}								\
 } while (0)
 
 #undef EASSERT
@@ -2125,27 +2126,24 @@ static void osc_check_rpcs(const struct lu_env *env, struct client_obd *cli,
 static int osc_io_unplug0(const struct lu_env *env, struct client_obd *cli,
 			  struct osc_object *osc, pdl_policy_t pol, int async)
 {
-	int has_rpcs = 1;
 	int rc = 0;
 
-	client_obd_list_lock(&cli->cl_loi_list_lock);
-	if (osc != NULL)
-		has_rpcs = __osc_list_maint(cli, osc);
-	if (has_rpcs) {
-		if (!async) {
-			/* disable osc_lru_shrink() temporarily to avoid
-			 * potential stack overrun problem. LU-2859 */
-			atomic_inc(&cli->cl_lru_shrinkers);
-			osc_check_rpcs(env, cli, pol);
-			atomic_dec(&cli->cl_lru_shrinkers);
-		} else {
-			CDEBUG(D_CACHE, "Queue writeback work for client %p.\n",
-			       cli);
-			LASSERT(cli->cl_writeback_work != NULL);
-			rc = ptlrpcd_queue_work(cli->cl_writeback_work);
-		}
+	if (osc != NULL && osc_list_maint(cli, osc) == 0)
+		return 0;
+
+	if (!async) {
+		/* disable osc_lru_shrink() temporarily to avoid
+		 * potential stack overrun problem. LU-2859 */
+		atomic_inc(&cli->cl_lru_shrinkers);
+		client_obd_list_lock(&cli->cl_loi_list_lock);
+		osc_check_rpcs(env, cli, pol);
+		client_obd_list_unlock(&cli->cl_loi_list_lock);
+		atomic_dec(&cli->cl_lru_shrinkers);
+	} else {
+		CDEBUG(D_CACHE, "Queue writeback work for client %p.\n", cli);
+		LASSERT(cli->cl_writeback_work != NULL);
+		rc = ptlrpcd_queue_work(cli->cl_writeback_work);
 	}
-	client_obd_list_unlock(&cli->cl_loi_list_lock);
 	return rc;
 }
 

drivers/staging/lustre/lustre/osc/osc_cl_internal.h

@@ -584,8 +584,6 @@ enum osc_extent_state {
 	OES_TRUNC     = 6, /** being truncated */
 	OES_STATE_MAX
 };
-#define OES_STRINGS { "inv", "active", "cache", "locking", "lockdone", "rpc", \
-		      "trunc", NULL }
 
 /**
  * osc_extent data to manage dirty pages.

drivers/staging/lustre/lustre/osc/osc_page.c

@@ -806,7 +806,8 @@ static void osc_lru_del(struct client_obd *cli, struct osc_page *opg, bool del)
 			 * stealing one of them.
 			 * cl_lru_shrinkers is to avoid recursive call in case
 			 * we're already in the context of osc_lru_shrink(). */
-			if (atomic_read(&cli->cl_lru_shrinkers) == 0)
+			if (atomic_read(&cli->cl_lru_shrinkers) == 0 &&
+			    !memory_pressure_get())
 				osc_lru_shrink(cli, osc_cache_too_much(cli));
 			wake_up(&osc_lru_waitq);
 		}

drivers/staging/lustre/lustre/osc/osc_request.c

@@ -2041,21 +2041,26 @@ static int brw_interpret(const struct lu_env *env,
 int osc_build_rpc(const struct lu_env *env, struct client_obd *cli,
 		  struct list_head *ext_list, int cmd, pdl_policy_t pol)
 {
-	struct ptlrpc_request *req = NULL;
-	struct osc_extent *ext;
+	struct ptlrpc_request		*req = NULL;
+	struct osc_extent		*ext;
+	struct brw_page			**pga = NULL;
+	struct osc_brw_async_args	*aa = NULL;
+	struct obdo			*oa = NULL;
+	struct osc_async_page		*oap;
+	struct osc_async_page		*tmp;
+	struct cl_req			*clerq = NULL;
+	enum cl_req_type		crt = (cmd & OBD_BRW_WRITE) ? CRT_WRITE :
+								      CRT_READ;
+	struct ldlm_lock		*lock = NULL;
+	struct cl_req_attr		*crattr = NULL;
+	obd_off				starting_offset = OBD_OBJECT_EOF;
+	obd_off				ending_offset = 0;
+	int				mpflag = 0;
+	int				mem_tight = 0;
+	int				page_count = 0;
+	int				i;
+	int				rc;
 	LIST_HEAD(rpc_list);
-	struct brw_page **pga = NULL;
-	struct osc_brw_async_args *aa = NULL;
-	struct obdo *oa = NULL;
-	struct osc_async_page *oap;
-	struct osc_async_page *tmp;
-	struct cl_req *clerq = NULL;
-	enum cl_req_type crt = (cmd & OBD_BRW_WRITE) ? CRT_WRITE : CRT_READ;
-	struct ldlm_lock *lock = NULL;
-	struct cl_req_attr crattr;
-	obd_off starting_offset = OBD_OBJECT_EOF;
-	obd_off ending_offset = 0;
-	int i, rc, mpflag = 0, mem_tight = 0, page_count = 0;
 
 	ENTRY;
 	LASSERT(!list_empty(ext_list));
@@ -2083,7 +2088,10 @@ int osc_build_rpc(const struct lu_env *env, struct client_obd *cli,
 	if (mem_tight)
 		mpflag = cfs_memory_pressure_get_and_set();
 
-	memset(&crattr, 0, sizeof crattr);
+	OBD_ALLOC(crattr, sizeof(*crattr));
+	if (crattr == NULL)
+		GOTO(out, rc = -ENOMEM);
+
 	OBD_ALLOC(pga, sizeof(*pga) * page_count);
 	if (pga == NULL)
 		GOTO(out, rc = -ENOMEM);
@@ -2097,8 +2105,7 @@ int osc_build_rpc(const struct lu_env *env, struct client_obd *cli,
 		struct cl_page *page = oap2cl_page(oap);
 		if (clerq == NULL) {
 			clerq = cl_req_alloc(env, page, crt,
-					     1 /* only 1-object rpcs for
-						* now */);
+					     1 /* only 1-object rpcs for now */);
 			if (IS_ERR(clerq))
 				GOTO(out, rc = PTR_ERR(clerq));
 			lock = oap->oap_ldlm_lock;
@@ -2108,17 +2115,16 @@ int osc_build_rpc(const struct lu_env *env, struct client_obd *cli,
 		pga[i] = &oap->oap_brw_page;
 		pga[i]->off = oap->oap_obj_off + oap->oap_page_off;
 		CDEBUG(0, "put page %p index %lu oap %p flg %x to pga\n",
-		       pga[i]->pg, page_index(oap->oap_page), oap, pga[i]->flag);
+		       pga[i]->pg, page_index(oap->oap_page), oap,
+		       pga[i]->flag);
 		i++;
 		cl_req_page_add(env, clerq, page);
 	}
 
 	/* always get the data for the obdo for the rpc */
 	LASSERT(clerq != NULL);
-	crattr.cra_oa = oa;
-	crattr.cra_capa = NULL;
-	memset(crattr.cra_jobid, 0, JOBSTATS_JOBID_SIZE);
-	cl_req_attr_set(env, clerq, &crattr, ~0ULL);
+	crattr->cra_oa = oa;
+	cl_req_attr_set(env, clerq, crattr, ~0ULL);
 	if (lock) {
 		oa->o_handle = lock->l_remote_handle;
 		oa->o_valid |= OBD_MD_FLHANDLE;
@@ -2132,7 +2138,7 @@ int osc_build_rpc(const struct lu_env *env, struct client_obd *cli,
 
 	sort_brw_pages(pga, page_count);
 	rc = osc_brw_prep_request(cmd, cli, oa, NULL, page_count,
-			pga, &req, crattr.cra_capa, 1, 0);
+			pga, &req, crattr->cra_capa, 1, 0);
 	if (rc != 0) {
 		CERROR("prep_req failed: %d\n", rc);
 		GOTO(out, rc);
@@ -2148,10 +2154,10 @@ int osc_build_rpc(const struct lu_env *env, struct client_obd *cli,
 	 * later setattr before earlier BRW (as determined by the request xid),
 	 * the OST will not use BRW timestamps.  Sadly, there is no obvious
 	 * way to do this in a single call.  bug 10150 */
-	cl_req_attr_set(env, clerq, &crattr,
+	cl_req_attr_set(env, clerq, crattr,
 			OBD_MD_FLMTIME|OBD_MD_FLCTIME|OBD_MD_FLATIME);
 
-	lustre_msg_set_jobid(req->rq_reqmsg, crattr.cra_jobid);
+	lustre_msg_set_jobid(req->rq_reqmsg, crattr->cra_jobid);
 
 	CLASSERT(sizeof(*aa) <= sizeof(req->rq_async_args));
 	aa = ptlrpc_req_async_args(req);
@@ -2218,7 +2224,11 @@ int osc_build_rpc(const struct lu_env *env, struct client_obd *cli,
 	if (mem_tight != 0)
 		cfs_memory_pressure_restore(mpflag);
 
-	capa_put(crattr.cra_capa);
+	if (crattr != NULL) {
+		capa_put(crattr->cra_capa);
+		OBD_FREE(crattr, sizeof(*crattr));
+	}
+
 	if (rc != 0) {
 		LASSERT(req == NULL);