LU-15619 osc: Remove oap lock

The OAP lock is taken around setting the oap flags, but not
any of the other fields in oap.  As far as I can tell, this
is just some cargo cult belief about locking - there's no
reason for it.

Remove it entirely.  (From the code, a queued spin lock
appears to be 12 bytes on x86_64.)

Signed-off-by: Patrick Farrell <pfarrell@whamcloud.com>
Change-Id: Ib61190d52c08d88c95a0c19b8ef7d114e26cfae2
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/46719
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Zhenyu Xu <bobijam@hotmail.com>

diff --git a/lustre/include/lustre_osc.h b/lustre/include/lustre_osc.h
index 8b574b8..38abb70 100644 (file)
--- a/lustre/include/lustre_osc.h
+++ b/lustre/include/lustre_osc.h
@@ -84,8 +84,6 @@ struct osc_async_page {
 
        struct ptlrpc_request   *oap_request;
        struct osc_object       *oap_obj;
-
-       spinlock_t               oap_lock;
 };
 
 #define oap_page       oap_brw_page.pg

diff --git a/lustre/osc/osc_cache.c b/lustre/osc/osc_cache.c
index fb9b003..20408c0 100644 (file)
--- a/lustre/osc/osc_cache.c
+++ b/lustre/osc/osc_cache.c
@@ -1095,9 +1095,7 @@ static int osc_extent_make_ready(const struct lu_env *env,
                rc = osc_make_ready(env, oap, OBD_BRW_WRITE);
                switch (rc) {
                case 0:
-                       spin_lock(&oap->oap_lock);
                        oap->oap_async_flags |= ASYNC_READY;
-                       spin_unlock(&oap->oap_lock);
                        break;
                case -EALREADY:
                        LASSERT((oap->oap_async_flags & ASYNC_READY) != 0);
@@ -1117,9 +1115,7 @@ static int osc_extent_make_ready(const struct lu_env *env,
                         "last_oap_count %d\n", last_oap_count);
                LASSERT(last->oap_page_off + last_oap_count <= PAGE_SIZE);
                last->oap_count = last_oap_count;
-               spin_lock(&last->oap_lock);
                last->oap_async_flags |= ASYNC_COUNT_STABLE;
-               spin_unlock(&last->oap_lock);
        }
 
        /* for the rest of pages, we don't need to call osf_refresh_count()
@@ -1127,9 +1123,7 @@ static int osc_extent_make_ready(const struct lu_env *env,
        list_for_each_entry(oap, &ext->oe_pages, oap_pending_item) {
                if (!(oap->oap_async_flags & ASYNC_COUNT_STABLE)) {
                        oap->oap_count = PAGE_SIZE - oap->oap_page_off;
-                       spin_lock(&oap->oap_lock);
                        oap->oap_async_flags |= ASYNC_COUNT_STABLE;
-                       spin_unlock(&oap->oap_lock);
                }
        }
 
@@ -1794,9 +1788,7 @@ static void osc_ap_completion(const struct lu_env *env, struct client_obd *cli,
        }
 
        /* As the transfer for this page is being done, clear the flags */
-       spin_lock(&oap->oap_lock);
        oap->oap_async_flags = 0;
-       spin_unlock(&oap->oap_lock);
 
        if (oap->oap_cmd & OBD_BRW_WRITE && xid > 0) {
                spin_lock(&cli->cl_loi_list_lock);
@@ -2264,7 +2256,6 @@ int osc_prep_async_page(struct osc_object *osc, struct osc_page *ops,
        INIT_LIST_HEAD(&oap->oap_pending_item);
        INIT_LIST_HEAD(&oap->oap_rpc_item);
 
-       spin_lock_init(&oap->oap_lock);
        CDEBUG(D_INFO, "oap %p vmpage %p obj off %llu\n",
               oap, vmpage, oap->oap_obj_off);
        RETURN(0);
@@ -2546,9 +2537,7 @@ int osc_flush_async_page(const struct lu_env *env, struct cl_io *io,
        if (rc)
                GOTO(out, rc);
 
-       spin_lock(&oap->oap_lock);
        oap->oap_async_flags |= ASYNC_READY|ASYNC_URGENT;
-       spin_unlock(&oap->oap_lock);
 
        if (current->flags & PF_MEMALLOC)
                ext->oe_memalloc = 1;

diff --git a/lustre/osc/osc_io.c b/lustre/osc/osc_io.c
index aea22bb..f06dec3 100644 (file)
--- a/lustre/osc/osc_io.c
+++ b/lustre/osc/osc_io.c
@@ -194,10 +194,7 @@ int osc_io_submit(const struct lu_env *env, const struct cl_io_slice *ios,
                 }
 
                if (page->cp_type != CPT_TRANSIENT) {
-                       spin_lock(&oap->oap_lock);
-                       oap->oap_async_flags = ASYNC_URGENT|ASYNC_READY;
-                       oap->oap_async_flags |= ASYNC_COUNT_STABLE;
-                       spin_unlock(&oap->oap_lock);
+                       oap->oap_async_flags = ASYNC_URGENT|ASYNC_READY|ASYNC_COUNT_STABLE;
                }
 
                osc_page_submit(env, opg, crt, brw_flags);

diff --git a/lustre/osc/osc_page.c b/lustre/osc/osc_page.c
index 857545d..06aff96 100644 (file)
--- a/lustre/osc/osc_page.c
+++ b/lustre/osc/osc_page.c
@@ -207,12 +207,7 @@ static void osc_page_clip(const struct lu_env *env,
        opg->ops_from = from;
        /* argument @to is exclusive, but @ops_to is inclusive */
        opg->ops_to   = to - 1;
-       /* This isn't really necessary for transient pages, but we also don't
-        * call clip on transient pages often, so it's OK.
-        */
-       spin_lock(&oap->oap_lock);
        oap->oap_async_flags |= ASYNC_COUNT_STABLE;
-       spin_unlock(&oap->oap_lock);
 }
 
 static int osc_page_flush(const struct lu_env *env,