LU-2139 osc: Use SOFT_SYNC to urge server commit

[fs/lustre-release.git] / lustre / osc / osc_page.c

diff --git a/lustre/osc/osc_page.c b/lustre/osc/osc_page.c
index cba22fe..affd0d2 100644 (file)
--- a/lustre/osc/osc_page.c
+++ b/lustre/osc/osc_page.c
@@ -70,7 +70,7 @@ static int osc_page_is_dlocked(const struct lu_env *env,
        struct lustre_handle   *lockh;
        ldlm_policy_data_t     *policy;
        ldlm_mode_t             dlmmode;
-       int                     flags;
+       __u64                   flags;
 
        might_sleep();
 
@@ -544,6 +544,30 @@ int osc_page_init(const struct lu_env *env, struct cl_object *obj,
        return result;
 }
 
+int osc_over_unstable_soft_limit(struct client_obd *cli)
+{
+       long obd_upages, obd_dpages, osc_upages;
+
+       /* Can't check cli->cl_unstable_count, therefore, no soft limit */
+       if (cli == NULL)
+               return 0;
+
+       obd_upages = cfs_atomic_read(&obd_unstable_pages);
+       obd_dpages = cfs_atomic_read(&obd_dirty_pages);
+
+       osc_upages = cfs_atomic_read(&cli->cl_unstable_count);
+
+       /* obd_max_dirty_pages is the max number of (dirty + unstable)
+        * pages allowed at any given time. To simulate an unstable page
+        * only limit, we subtract the current number of dirty pages
+        * from this max. This difference is roughly the amount of pages
+        * currently available for unstable pages. Thus, the soft limit
+        * is half of that difference. Check osc_upages to ensure we don't
+        * set SOFT_SYNC for OSCs without any outstanding unstable pages. */
+       return osc_upages != 0 &&
+              obd_upages >= (obd_max_dirty_pages - obd_dpages) / 2;
+}
+
 /**
  * Helper function called by osc_io_submit() for every page in an immediate
  * transfer (i.e., transferred synchronously).
@@ -567,6 +591,9 @@ void osc_page_submit(const struct lu_env *env, struct osc_page *opg,
        oap->oap_count     = opg->ops_to - opg->ops_from;
        oap->oap_brw_flags = OBD_BRW_SYNC | brw_flags;
 
+       if (osc_over_unstable_soft_limit(oap->oap_cli))
+               oap->oap_brw_flags |= OBD_BRW_SOFT_SYNC;
+
        if (!client_is_remote(osc_export(obj)) &&
                        cfs_capable(CFS_CAP_SYS_RESOURCE)) {
                oap->oap_brw_flags |= OBD_BRW_NOQUOTA;