LU-13799 lov: Cache stripe offset calculation

[fs/lustre-release.git] / lustre / lov / lov_page.c

diff --git a/lustre/lov/lov_page.c b/lustre/lov/lov_page.c
index 48ef262..887b304 100644 (file)
--- a/lustre/lov/lov_page.c
+++ b/lustre/lov/lov_page.c
@@ -27,7 +27,6 @@
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
- * Lustre is a trademark of Sun Microsystems, Inc.
  *
  * Implementation of cl_page for LOV layer.
  *
@@ -56,8 +55,7 @@ static int lov_comp_page_print(const struct lu_env *env,
        struct lov_page *lp = cl2lov_page(slice);
 
        return (*printer)(env, cookie,
-                         LUSTRE_LOV_NAME"-page@%p, gen: %u\n",
-                         lp, lp->lps_layout_gen);
+                         LUSTRE_LOV_NAME"-page@%p\n", lp);
 }
 
 static const struct cl_page_operations lov_comp_page_ops = {
@@ -76,37 +74,68 @@ int lov_page_init_composite(const struct lu_env *env, struct cl_object *obj,
        struct lov_layout_raid0 *r0;
        loff_t offset;
        loff_t suboff;
+       bool stripe_cached = false;
        int entry;
        int stripe;
        int rc;
 
        ENTRY;
 
+       /* Direct i/o (CPT_TRANSIENT) is split strictly to stripes, so we can
+        * cache the stripe information.  Buffered i/o is differently
+        * organized, and stripe calculation isn't a significant cost for
+        * buffered i/o, so we only cache this for direct i/o.
+        */
+       stripe_cached = lio->lis_cached_entry != LIS_CACHE_ENTRY_NONE &&
+                       page->cp_type == CPT_TRANSIENT;
+
        offset = cl_offset(obj, index);
-       entry = lov_io_layout_at(lio, offset);
+
+       if (stripe_cached) {
+               entry = lio->lis_cached_entry;
+               stripe = lio->lis_cached_stripe;
+               /* Offset can never go backwards in an i/o, so this is valid */
+               suboff = lio->lis_cached_suboff + offset - lio->lis_cached_off;
+       } else {
+               entry = lov_io_layout_at(lio, offset);
+
+               stripe = lov_stripe_number(loo->lo_lsm, entry, offset);
+               rc = lov_stripe_offset(loo->lo_lsm, entry, offset, stripe,
+                                      &suboff);
+               LASSERT(rc == 0);
+               lio->lis_cached_entry = entry;
+               lio->lis_cached_stripe = stripe;
+               lio->lis_cached_off = offset;
+               lio->lis_cached_suboff = suboff;
+       }
+
        if (entry < 0 || !lsm_entry_inited(loo->lo_lsm, entry)) {
                /* non-existing layout component */
                lov_page_init_empty(env, obj, page, index);
                RETURN(0);
        }
 
-       r0 = lov_r0(loo, entry);
-       stripe = lov_stripe_number(loo->lo_lsm, entry, offset);
-       LASSERT(stripe < r0->lo_nr);
-       rc = lov_stripe_offset(loo->lo_lsm, entry, offset, stripe, &suboff);
-       LASSERT(rc == 0);
+       CDEBUG(D_PAGE, "offset %llu, entry %d, stripe %d, suboff %llu\n",
+              offset, entry, stripe, suboff);
 
        page->cp_lov_index = lov_comp_index(entry, stripe);
-       lpg->lps_layout_gen = loo->lo_lsm->lsm_layout_gen;
        cl_page_slice_add(page, &lpg->lps_cl, obj, &lov_comp_page_ops);
 
-       sub = lov_sub_get(env, lio, page->cp_lov_index);
-       if (IS_ERR(sub))
-               RETURN(PTR_ERR(sub));
+       if (!stripe_cached) {
+               sub = lov_sub_get(env, lio, page->cp_lov_index);
+               if (IS_ERR(sub))
+                       RETURN(PTR_ERR(sub));
+       } else {
+               sub = lio->lis_cached_sub;
+       }
+
+       lio->lis_cached_sub = sub;
+
+       r0 = lov_r0(loo, entry);
+       LASSERT(stripe < r0->lo_nr);
 
        subobj = lovsub2cl(r0->lo_sub[stripe]);
-       list_for_each_entry(o, &subobj->co_lu.lo_header->loh_layers,
-                           co_lu.lo_linkage) {
+       cl_object_for_each(o, subobj) {
                if (o->co_ops->coo_page_init) {
                        rc = o->co_ops->coo_page_init(sub->sub_env, o, page,
                                                      cl_index(subobj, suboff));