On Wed, 2024-08-28 at 18:17 -0400, Benjamin Marzinski wrote:
> Instead of updating the path priorities and possibly reloading the
> multipath device when each path is updated, wait till all paths
> have been updated, and then go through the multipath devices updating
> the priorities once, reloading if necessary.
>
> Signed-off-by: Benjamin Marzinski <bmarz...@redhat.com>
> ---
> libmultipath/structs.h | 9 +++
> multipathd/main.c | 169 ++++++++++++++++++++++++++-------------
> --
> 2 files changed, 118 insertions(+), 60 deletions(-)
>
> diff --git a/libmultipath/structs.h b/libmultipath/structs.h
> index af8e31e9..1f531d30 100644
> --- a/libmultipath/structs.h
> +++ b/libmultipath/structs.h
> @@ -318,6 +318,7 @@ enum check_path_states {
> CHECK_PATH_UNCHECKED,
> CHECK_PATH_STARTED,
> CHECK_PATH_CHECKED,
> + CHECK_PATH_NEW_UP,
> CHECK_PATH_SKIPPED,
> CHECK_PATH_REMOVED,
> };
> @@ -421,6 +422,13 @@ enum prflag_value {
> PRFLAG_SET,
> };
>
> +enum prio_update_type {
> + PRIO_UPDATE_NONE,
> + PRIO_UPDATE_NORMAL,
> + PRIO_UPDATE_NEW_PATH,
> + PRIO_UPDATE_MARGINAL,
> +};
> +
> struct multipath {
> char wwid[WWID_SIZE];
> char alias_old[WWID_SIZE];
> @@ -464,6 +472,7 @@ struct multipath {
> int queue_mode;
> unsigned int sync_tick;
> int synced_count;
> + enum prio_update_type prio_update;
> uid_t uid;
> gid_t gid;
> mode_t mode;
> diff --git a/multipathd/main.c b/multipathd/main.c
> index 2bcc6066..1511f701 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -1996,15 +1996,13 @@ mpvec_garbage_collector (struct vectors *
> vecs)
> * best pathgroup, and this is the first path in the pathgroup to
> come back
> * up, then switch to this pathgroup */
> static int
> -followover_should_failback(struct path * pp)
> +do_followover_should_failback(struct path * pp)
> {
> struct pathgroup * pgp;
> struct path *pp1;
> int i;
>
> - if (pp->mpp->pgfailback != -FAILBACK_FOLLOWOVER ||
> - !pp->mpp->pg || !pp->pgindex ||
> - pp->pgindex != pp->mpp->bestpg)
> + if (pp->pgindex != pp->mpp->bestpg)
> return 0;
What happened to the !pp->pgindex test? Is it not necessary any more?
>
> pgp = VECTOR_SLOT(pp->mpp->pg, pp->pgindex - 1);
> @@ -2017,6 +2015,26 @@ followover_should_failback(struct path * pp)
> return 1;
> }
>
> +static int
> +followover_should_failback(struct multipath *mpp)
> +{
> + struct path *pp;
> + struct pathgroup * pgp;
> + int i, j;
> +
> + if (mpp->pgfailback != -FAILBACK_FOLLOWOVER || !mpp->pg ||
> !mpp->bestpg)
> + return 0;
> +
> + vector_foreach_slot (mpp->pg, pgp, i) {
> + vector_foreach_slot (pgp->paths, pp, j) {
> + if (pp->is_checked == CHECK_PATH_NEW_UP &&
> + do_followover_should_failback(pp))
> + return 1;
> + }
> + }
> + return 0;
> +}
> +
> static void
> missing_uev_wait_tick(struct vectors *vecs)
> {
> @@ -2132,41 +2150,53 @@ partial_retrigger_tick(vector pathvec)
> }
> }
>
> -static int update_prio(struct path *pp, int force_refresh_all)
> +static bool update_prio(struct multipath *mpp, bool refresh_all)
> {
> int oldpriority;
> - struct path *pp1;
> + struct path *pp;
> struct pathgroup * pgp;
> - int i, j, changed = 0;
> + int i, j;
> + bool changed = false;
> + bool skipped_path = false;
> struct config *conf;
>
> - oldpriority = pp->priority;
> - if (pp->state != PATH_DOWN) {
> - conf = get_multipath_config();
> - pthread_cleanup_push(put_multipath_config, conf);
> - pathinfo(pp, conf, DI_PRIO);
> - pthread_cleanup_pop(1);
> + vector_foreach_slot (mpp->pg, pgp, i) {
> + vector_foreach_slot (pgp->paths, pp, j) {
> + if (pp->state != PATH_UP && pp->state !=
> PATH_GHOST)
> + continue;
This test used to be pp->state == PATH_DOWN (see below).
Just trying to confirm that you did this on purpose. It might justify a
separate patch, with rationale. After all, AFAICS, we will now keep the
old priority for all path states except PATH_UP and PATH_GHOST, while
previously we attempted to fetch the prio for most of them, and only
used the previous value if fetching the prio failed.
> + if (!refresh_all &&
> + pp->is_checked != CHECK_PATH_CHECKED) {
> + skipped_path = true;
> + continue;
> + }
> + oldpriority = pp->priority;
> + conf = get_multipath_config();
> + pthread_cleanup_push(put_multipath_config,
> conf);
> + pathinfo(pp, conf, DI_PRIO);
> + pthread_cleanup_pop(1);
> + if (pp->priority != oldpriority)
> + changed = true;
> + }
> }
> -
> - if (pp->priority != oldpriority)
> - changed = 1;
> - else if (!force_refresh_all)
> - return 0;
> -
> - vector_foreach_slot (pp->mpp->pg, pgp, i) {
> - vector_foreach_slot (pgp->paths, pp1, j) {
> - if (pp1 == pp || pp1->state == PATH_DOWN)
> + if (!changed || !skipped_path)
> + return changed;
> + /*
> + * If a path changed priorities, refresh the priorities of
> any
> + * paths we skipped
> + */
> + vector_foreach_slot (mpp->pg, pgp, i) {
> + vector_foreach_slot (pgp->paths, pp, j) {
> + if (pp->state != PATH_UP && pp->state !=
> PATH_GHOST)
> + continue;
> + if (pp->is_checked == CHECK_PATH_CHECKED)
> continue;
> - oldpriority = pp1->priority;
> conf = get_multipath_config();
> pthread_cleanup_push(put_multipath_config,
> conf);
> - pathinfo(pp1, conf, DI_PRIO);
> + pathinfo(pp, conf, DI_PRIO);
> pthread_cleanup_pop(1);
> - if (pp1->priority != oldpriority)
> - changed = 1;
> }
> }
> - return changed;
> + return true;
> }
>
> static int reload_map(struct vectors *vecs, struct multipath *mpp,
> @@ -2393,14 +2423,12 @@ static int
> update_path_state (struct vectors * vecs, struct path * pp)
> {
> int newstate;
> - int new_path_up = 0;
> int chkr_new_path_up = 0;
> int disable_reinstate = 0;
> int oldchkrstate = pp->chkrstate;
> unsigned int checkint, max_checkint;
> struct config *conf;
> - int marginal_pathgroups, marginal_changed = 0;
> - bool need_reload;
> + int marginal_pathgroups;
>
> conf = get_multipath_config();
> checkint = conf->checkint;
> @@ -2462,7 +2490,7 @@ update_path_state (struct vectors * vecs,
> struct path * pp)
> }
> if (!pp->marginal) {
> pp->marginal = 1;
> - marginal_changed = 1;
> + pp->mpp->prio_update =
> PRIO_UPDATE_MARGINAL;
> }
> } else {
> if (pp->marginal || pp->state ==
> PATH_DELAYED)
> @@ -2470,7 +2498,7 @@ update_path_state (struct vectors * vecs,
> struct path * pp)
> pp->dev);
> if (marginal_pathgroups && pp->marginal) {
> pp->marginal = 0;
> - marginal_changed = 1;
> + pp->mpp->prio_update =
> PRIO_UPDATE_MARGINAL;
> }
> }
> }
> @@ -2537,7 +2565,8 @@ update_path_state (struct vectors * vecs,
> struct path * pp)
> */
> if (!disable_reinstate)
> reinstate_path(pp);
> - new_path_up = 1;
> + if (pp->mpp->prio_update != PRIO_UPDATE_MARGINAL)
> + pp->mpp->prio_update = PRIO_UPDATE_NEW_PATH;
>
> if (oldchkrstate != PATH_UP && oldchkrstate !=
> PATH_GHOST)
> chkr_new_path_up = 1;
> @@ -2588,38 +2617,48 @@ update_path_state (struct vectors * vecs,
> struct path * pp)
> LOG_MSG(2, pp);
> }
> }
> -
> + if (pp->mpp->prio_update == PRIO_UPDATE_NONE &&
> + (newstate == PATH_UP || newstate == PATH_GHOST))
> + pp->mpp->prio_update = PRIO_UPDATE_NORMAL;
> pp->state = newstate;
> + return chkr_new_path_up ? CHECK_PATH_NEW_UP :
> CHECK_PATH_CHECKED;
> +}
>
> - if (pp->mpp->wait_for_udev)
> - return CHECK_PATH_CHECKED;
> - /*
> - * path prio refreshing
> - */
> - condlog(4, "path prio refresh");
> -
> - if (marginal_changed) {
> - update_prio(pp, 1);
> - reload_and_sync_map(pp->mpp, vecs);
> - } else if (update_prio(pp, new_path_up) &&
> - pp->mpp->pgpolicyfn == (pgpolicyfn
> *)group_by_prio &&
> - pp->mpp->pgfailback == -FAILBACK_IMMEDIATE) {
> +static int
> +update_mpp_prio(struct vectors *vecs, struct multipath *mpp)
> +{
> + bool need_reload, changed;
> + enum prio_update_type prio_update = mpp->prio_update;
> + mpp->prio_update = PRIO_UPDATE_NONE;
> +
> + if (mpp->wait_for_udev || prio_update == PRIO_UPDATE_NONE)
> + return 0;
> + condlog(4, "prio refresh");
> +
> + changed = update_prio(mpp, prio_update !=
> PRIO_UPDATE_NORMAL);
> + if (prio_update == PRIO_UPDATE_MARGINAL)
> + return reload_and_sync_map(mpp, vecs);
> + if (changed && mpp->pgpolicyfn == (pgpolicyfn
> *)group_by_prio &&
> + mpp->pgfailback == -FAILBACK_IMMEDIATE) {
> condlog(2, "%s: path priorities changed. reloading",
> - pp->mpp->alias);
> - reload_and_sync_map(pp->mpp, vecs);
> - } else if (need_switch_pathgroup(pp->mpp, &need_reload)) {
> - if (pp->mpp->pgfailback > 0 &&
> - (new_path_up || pp->mpp->failback_tick <= 0))
> - pp->mpp->failback_tick = pp->mpp->pgfailback
> + 1;
> - else if (pp->mpp->pgfailback == -FAILBACK_IMMEDIATE
> ||
> - (chkr_new_path_up &&
> followover_should_failback(pp))) {
> + mpp->alias);
> + return reload_and_sync_map(mpp, vecs);
> + }
> + if (need_switch_pathgroup(mpp, &need_reload)) {
> + if (mpp->pgfailback > 0 &&
> + (prio_update == PRIO_UPDATE_NEW_PATH ||
> + mpp->failback_tick <= 0))
> + mpp->failback_tick = mpp->pgfailback + 1;
> + else if (mpp->pgfailback == -FAILBACK_IMMEDIATE ||
> + (prio_update == PRIO_UPDATE_NEW_PATH &&
> + followover_should_failback(mpp))) {
> if (need_reload)
> - reload_and_sync_map(pp->mpp, vecs);
> + return reload_and_sync_map(mpp,
> vecs);
> else
> - switch_pathgroup(pp->mpp);
> + switch_pathgroup(mpp);
> }
> }
> - return CHECK_PATH_CHECKED;
> + return 0;
> }
>
> static int
> @@ -2859,7 +2898,7 @@ update_paths(struct vectors *vecs, int
> *num_paths_p, time_t start_secs)
> i--;
> else {
> pp->is_checked = rc;
> - if (rc == CHECK_PATH_CHECKED)
> + if (rc == CHECK_PATH_CHECKED ||
> CHECK_PATH_NEW_UP)
> (*num_paths_p)++;
> }
> if (++paths_checked % 128 == 0 &&
> @@ -2932,8 +2971,10 @@ checkerloop (void *ap)
> vector_foreach_slot(vecs->mpvec, mpp, i)
> mpp->synced_count = 0;
> if (checker_state == CHECKER_STARTING) {
> - vector_foreach_slot(vecs->mpvec,
> mpp, i)
> + vector_foreach_slot(vecs->mpvec,
> mpp, i) {
> sync_mpp(vecs, mpp, ticks);
> + mpp->prio_update =
> PRIO_UPDATE_NONE;
> + }
> vector_foreach_slot(vecs->pathvec,
> pp, i)
> pp->is_checked =
> CHECK_PATH_UNCHECKED;
> checker_state =
> CHECKER_CHECKING_PATHS;
> @@ -2943,6 +2984,14 @@ checkerloop (void *ap)
> if (checker_state == CHECKER_UPDATING_PATHS)
> checker_state = update_paths(vecs,
> &num_paths,
>
> start_time.tv_sec);
> + if (checker_state == CHECKER_FINISHED) {
> + vector_foreach_slot(vecs->mpvec,
> mpp, i) {
> + if (update_mpp_prio(vecs,
> mpp) == 2) {
> + /* multipath device
> deleted */
> + i--;
> + }
> + }
> + }
> lock_cleanup_pop(vecs->lock);
> if (checker_state != CHECKER_FINISHED) {
> /* Yield to waiters */
