diff options
-rw-r--r-- | drivers/staging/lustre/lnet/lnet/lib-ptl.c | 84 |
1 files changed, 53 insertions, 31 deletions
diff --git a/drivers/staging/lustre/lnet/lnet/lib-ptl.c b/drivers/staging/lustre/lnet/lnet/lib-ptl.c index 0281c6a..2b41205 100644 --- a/drivers/staging/lustre/lnet/lnet/lib-ptl.c +++ b/drivers/staging/lustre/lnet/lnet/lib-ptl.c @@ -472,10 +472,12 @@ lnet_ptl_match_delay(struct lnet_portal *ptl, int rc = 0; int i; - /* - * steal buffer from other CPTs, and delay it if nothing to steal, - * this function is more expensive than a regular match, but we - * don't expect it can happen a lot + /** + * Steal buffer from other CPTs, and delay msg if nothing to + * steal. This function is more expensive than a regular + * match, but we don't expect it can happen a lot. The return + * code contains one of LNET_MATCHMD_OK, LNET_MATCHMD_DROP, or + * LNET_MATCHMD_NONE. */ LASSERT(lnet_ptl_is_wildcard(ptl)); @@ -491,52 +493,71 @@ lnet_ptl_match_delay(struct lnet_portal *ptl, lnet_res_lock(cpt); lnet_ptl_lock(ptl); - if (!i) { /* the first try, attach on stealing list */ + if (!i) { + /* The first try, add to stealing list. */ list_add_tail(&msg->msg_list, &ptl->ptl_msg_stealing); } - if (!list_empty(&msg->msg_list)) { /* on stealing list */ + if (!list_empty(&msg->msg_list)) { + /* On stealing list. */ rc = lnet_mt_match_md(mtable, info, msg); if ((rc & LNET_MATCHMD_EXHAUSTED) && mtable->mt_enabled) lnet_ptl_disable_mt(ptl, cpt); - if (rc & LNET_MATCHMD_FINISH) + if (rc & LNET_MATCHMD_FINISH) { + /* Match found, remove from stealing list. */ + list_del_init(&msg->msg_list); + } else if (i == LNET_CPT_NUMBER - 1 || /* (1) */ + !ptl->ptl_mt_nmaps || /* (2) */ + (ptl->ptl_mt_nmaps == 1 && /* (3) */ + ptl->ptl_mt_maps[0] == cpt)) { + /** + * No match found, and this is either + * (1) the last cpt to check, or + * (2) there is no active cpt, or + * (3) this is the only active cpt. + * There is nothing to steal: delay or + * drop the message. + */ list_del_init(&msg->msg_list); + if (lnet_ptl_is_lazy(ptl)) { + msg->msg_rx_delayed = 1; + list_add_tail(&msg->msg_list, + &ptl->ptl_msg_delayed); + rc = LNET_MATCHMD_NONE; + } else { + rc = LNET_MATCHMD_DROP; + } + } else { + /* Do another iteration. */ + rc = 0; + } } else { - /* - * could be matched by lnet_ptl_attach_md() - * which is called by another thread + /** + * No longer on stealing list: another thread + * matched the message in lnet_ptl_attach_md(). + * We are now expected to handle the message. */ rc = !msg->msg_md ? LNET_MATCHMD_DROP : LNET_MATCHMD_OK; } - if (!list_empty(&msg->msg_list) && /* not matched yet */ - (i == LNET_CPT_NUMBER - 1 || /* the last CPT */ - !ptl->ptl_mt_nmaps || /* no active CPT */ - (ptl->ptl_mt_nmaps == 1 && /* the only active CPT */ - ptl->ptl_mt_maps[0] == cpt))) { - /* nothing to steal, delay or drop */ - list_del_init(&msg->msg_list); - - if (lnet_ptl_is_lazy(ptl)) { - msg->msg_rx_delayed = 1; - list_add_tail(&msg->msg_list, - &ptl->ptl_msg_delayed); - rc = LNET_MATCHMD_NONE; - } else { - rc = LNET_MATCHMD_DROP; - } - } - lnet_ptl_unlock(ptl); lnet_res_unlock(cpt); - if ((rc & LNET_MATCHMD_FINISH) || msg->msg_rx_delayed) + /** + * Note that test (1) above ensures that we always + * exit the loop through this break statement. + * + * LNET_MATCHMD_NONE means msg was added to the + * delayed queue, and we may no longer reference it + * after lnet_ptl_unlock() and lnet_res_unlock(). + */ + if (rc & (LNET_MATCHMD_FINISH | LNET_MATCHMD_NONE)) break; } @@ -598,13 +619,14 @@ lnet_ptl_match_md(struct lnet_match_info *info, struct lnet_msg *msg) lnet_ptl_unlock(ptl); lnet_res_unlock(mtable->mt_cpt); - + rc = LNET_MATCHMD_NONE; } else { lnet_res_unlock(mtable->mt_cpt); rc = lnet_ptl_match_delay(ptl, info, msg); } - if (msg->msg_rx_delayed) { + /* LNET_MATCHMD_NONE means msg was added to the delay queue */ + if (rc & LNET_MATCHMD_NONE) { CDEBUG(D_NET, "Delaying %s from %s ptl %d MB %#llx off %d len %d\n", info->mi_opc == LNET_MD_OP_PUT ? "PUT" : "GET", |