#include <linux/module.h>
#include <linux/list.h>
+#include <linux/random.h>
#include <libcfs/libcfs.h>
#include <libcfs/libcfs_hash.h> /* hash_long() */
#include <libcfs/linux/linux-mem.h>
#include <lustre_fid.h>
#include <lu_object.h>
+void lu_qos_rr_init(struct lu_qos_rr *lqr)
+{
+ spin_lock_init(&lqr->lqr_alloc);
+ lqr->lqr_dirty = 1;
+}
+EXPORT_SYMBOL(lu_qos_rr_init);
+
/**
* Add a new target to Quality of Service (QoS) target table.
*
RETURN(rc);
}
EXPORT_SYMBOL(lqos_del_tgt);
+
+/**
+ * lu_prandom_u64_max - returns a pseudo-random u64 number in interval
+ * [0, ep_ro)
+ *
+ * \param[in] ep_ro right open interval endpoint
+ *
+ * \retval a pseudo-random 64-bit number that is in interval [0, ep_ro).
+ */
+u64 lu_prandom_u64_max(u64 ep_ro)
+{
+ u64 rand = 0;
+
+ if (ep_ro) {
+#if BITS_PER_LONG == 32
+ /*
+ * If ep_ro > 32-bit, first generate the high
+ * 32 bits of the random number, then add in the low
+ * 32 bits (truncated to the upper limit, if needed)
+ */
+ if (ep_ro > 0xffffffffULL)
+ rand = prandom_u32_max((u32)(ep_ro >> 32)) << 32;
+
+ if (rand == (ep_ro & 0xffffffff00000000ULL))
+ rand |= prandom_u32_max((u32)ep_ro);
+ else
+ rand |= prandom_u32();
+#else
+ rand = ((u64)prandom_u32() << 32 | prandom_u32()) % ep_ro;
+#endif
+ }
+
+ return rand;
+}
+EXPORT_SYMBOL(lu_prandom_u64_max);
+
+static inline __u64 tgt_statfs_bavail(struct lu_tgt_desc *tgt)
+{
+ struct obd_statfs *statfs = &tgt->ltd_statfs;
+
+ return statfs->os_bavail * statfs->os_bsize;
+}
+
+static inline __u64 tgt_statfs_iavail(struct lu_tgt_desc *tgt)
+{
+ return tgt->ltd_statfs.os_ffree;
+}
+
+/**
+ * Calculate penalties per-tgt and per-server
+ *
+ * Re-calculate penalties when the configuration changes, active targets
+ * change and after statfs refresh (all these are reflected by lq_dirty flag).
+ * On every tgt and server: decay the penalty by half for every 8x the update
+ * interval that the device has been idle. That gives lots of time for the
+ * statfs information to be updated (which the penalty is only a proxy for),
+ * and avoids penalizing server/tgt under light load.
+ * See lqos_calc_weight() for how penalties are factored into the weight.
+ *
+ * \param[in] qos lu_qos
+ * \param[in] ltd lu_tgt_descs
+ * \param[in] active_tgt_nr active tgt number
+ * \param[in] maxage qos max age
+ * \param[in] is_mdt MDT will count inode usage
+ *
+ * \retval 0 on success
+ * \retval -EAGAIN the number of tgt isn't enough or all tgt spaces are
+ * almost the same
+ */
+int lqos_calc_penalties(struct lu_qos *qos, struct lu_tgt_descs *ltd,
+ __u32 active_tgt_nr, __u32 maxage, bool is_mdt)
+{
+ struct lu_tgt_desc *tgt;
+ struct lu_svr_qos *svr;
+ __u64 ba_max, ba_min, ba;
+ __u64 ia_max, ia_min, ia = 1;
+ __u32 num_active;
+ int prio_wide;
+ time64_t now, age;
+ int rc;
+
+ ENTRY;
+
+ if (!qos->lq_dirty)
+ GOTO(out, rc = 0);
+
+ num_active = active_tgt_nr - 1;
+ if (num_active < 1)
+ GOTO(out, rc = -EAGAIN);
+
+ /* find bavail on each server */
+ list_for_each_entry(svr, &qos->lq_svr_list, lsq_svr_list) {
+ svr->lsq_bavail = 0;
+ /* if inode is not counted, set to 1 to ignore */
+ svr->lsq_iavail = is_mdt ? 0 : 1;
+ }
+ qos->lq_active_svr_count = 0;
+
+ /*
+ * How badly user wants to select targets "widely" (not recently chosen
+ * and not on recent MDS's). As opposed to "freely" (free space avail.)
+ * 0-256
+ */
+ prio_wide = 256 - qos->lq_prio_free;
+
+ ba_min = (__u64)(-1);
+ ba_max = 0;
+ ia_min = (__u64)(-1);
+ ia_max = 0;
+ now = ktime_get_real_seconds();
+
+ /* Calculate server penalty per object */
+ ltd_foreach_tgt(ltd, tgt) {
+ if (!tgt->ltd_active)
+ continue;
+
+ /* when inode is counted, bavail >> 16 to avoid overflow */
+ ba = tgt_statfs_bavail(tgt);
+ if (is_mdt)
+ ba >>= 16;
+ else
+ ba >>= 8;
+ if (!ba)
+ continue;
+
+ ba_min = min(ba, ba_min);
+ ba_max = max(ba, ba_max);
+
+ /* Count the number of usable servers */
+ if (tgt->ltd_qos.ltq_svr->lsq_bavail == 0)
+ qos->lq_active_svr_count++;
+ tgt->ltd_qos.ltq_svr->lsq_bavail += ba;
+
+ if (is_mdt) {
+ /* iavail >> 8 to avoid overflow */
+ ia = tgt_statfs_iavail(tgt) >> 8;
+ if (!ia)
+ continue;
+
+ ia_min = min(ia, ia_min);
+ ia_max = max(ia, ia_max);
+
+ tgt->ltd_qos.ltq_svr->lsq_iavail += ia;
+ }
+
+ /*
+ * per-tgt penalty is
+ * prio * bavail * iavail / (num_tgt - 1) / 2
+ */
+ tgt->ltd_qos.ltq_penalty_per_obj = prio_wide * ba * ia >> 8;
+ do_div(tgt->ltd_qos.ltq_penalty_per_obj, num_active);
+ tgt->ltd_qos.ltq_penalty_per_obj >>= 1;
+
+ age = (now - tgt->ltd_qos.ltq_used) >> 3;
+ if (qos->lq_reset || age > 32 * maxage)
+ tgt->ltd_qos.ltq_penalty = 0;
+ else if (age > maxage)
+ /* Decay tgt penalty. */
+ tgt->ltd_qos.ltq_penalty >>= (age / maxage);
+ }
+
+ num_active = qos->lq_active_svr_count - 1;
+ if (num_active < 1) {
+ /*
+ * If there's only 1 server, we can't penalize it, so instead
+ * we have to double the tgt penalty
+ */
+ num_active = 1;
+ ltd_foreach_tgt(ltd, tgt) {
+ if (!tgt->ltd_active)
+ continue;
+
+ tgt->ltd_qos.ltq_penalty_per_obj <<= 1;
+ }
+ }
+
+ /*
+ * Per-server penalty is
+ * prio * bavail * iavail / server_tgts / (num_svr - 1) / 2
+ */
+ list_for_each_entry(svr, &qos->lq_svr_list, lsq_svr_list) {
+ ba = svr->lsq_bavail;
+ ia = svr->lsq_iavail;
+ svr->lsq_penalty_per_obj = prio_wide * ba * ia >> 8;
+ do_div(ba, svr->lsq_tgt_count * num_active);
+ svr->lsq_penalty_per_obj >>= 1;
+
+ age = (now - svr->lsq_used) >> 3;
+ if (qos->lq_reset || age > 32 * maxage)
+ svr->lsq_penalty = 0;
+ else if (age > maxage)
+ /* Decay server penalty. */
+ svr->lsq_penalty >>= age / maxage;
+ }
+
+ qos->lq_dirty = 0;
+ qos->lq_reset = 0;
+
+ /*
+ * If each tgt has almost same free space, do rr allocation for better
+ * creation performance
+ */
+ qos->lq_same_space = 0;
+ if ((ba_max * (256 - qos->lq_threshold_rr)) >> 8 < ba_min &&
+ (ia_max * (256 - qos->lq_threshold_rr)) >> 8 < ia_min) {
+ qos->lq_same_space = 1;
+ /* Reset weights for the next time we enter qos mode */
+ qos->lq_reset = 1;
+ }
+ rc = 0;
+
+out:
+ if (!rc && qos->lq_same_space)
+ RETURN(-EAGAIN);
+
+ RETURN(rc);
+}
+EXPORT_SYMBOL(lqos_calc_penalties);
+
+bool lqos_is_usable(struct lu_qos *qos, __u32 active_tgt_nr)
+{
+ if (!qos->lq_dirty && qos->lq_same_space)
+ return false;
+
+ if (active_tgt_nr < 2)
+ return false;
+
+ return true;
+}
+EXPORT_SYMBOL(lqos_is_usable);
+
+/**
+ * Calculate weight for a given tgt.
+ *
+ * The final tgt weight is bavail >> 16 * iavail >> 8 minus the tgt and server
+ * penalties. See lqos_calc_ppts() for how penalties are calculated.
+ *
+ * \param[in] tgt target descriptor
+ */
+void lqos_calc_weight(struct lu_tgt_desc *tgt)
+{
+ struct lu_tgt_qos *ltq = &tgt->ltd_qos;
+ __u64 temp, temp2;
+
+ temp = (tgt_statfs_bavail(tgt) >> 16) * (tgt_statfs_iavail(tgt) >> 8);
+ temp2 = ltq->ltq_penalty + ltq->ltq_svr->lsq_penalty;
+ if (temp < temp2)
+ ltq->ltq_weight = 0;
+ else
+ ltq->ltq_weight = temp - temp2;
+}
+EXPORT_SYMBOL(lqos_calc_weight);
+
+/**
+ * Re-calculate weights.
+ *
+ * The function is called when some target was used for a new object. In
+ * this case we should re-calculate all the weights to keep new allocations
+ * balanced well.
+ *
+ * \param[in] qos lu_qos
+ * \param[in] ltd lu_tgt_descs
+ * \param[in] tgt target where a new object was placed
+ * \param[in] active_tgt_nr active tgt number
+ * \param[out] total_wt new total weight for the pool
+ *
+ * \retval 0
+ */
+int lqos_recalc_weight(struct lu_qos *qos, struct lu_tgt_descs *ltd,
+ struct lu_tgt_desc *tgt, __u32 active_tgt_nr,
+ __u64 *total_wt)
+{
+ struct lu_tgt_qos *ltq;
+ struct lu_svr_qos *svr;
+
+ ENTRY;
+
+ ltq = &tgt->ltd_qos;
+ LASSERT(ltq);
+
+ /* Don't allocate on this device anymore, until the next alloc_qos */
+ ltq->ltq_usable = 0;
+
+ svr = ltq->ltq_svr;
+
+ /*
+ * Decay old penalty by half (we're adding max penalty, and don't
+ * want it to run away.)
+ */
+ ltq->ltq_penalty >>= 1;
+ svr->lsq_penalty >>= 1;
+
+ /* mark the server and tgt as recently used */
+ ltq->ltq_used = svr->lsq_used = ktime_get_real_seconds();
+
+ /* Set max penalties for this tgt and server */
+ ltq->ltq_penalty += ltq->ltq_penalty_per_obj * active_tgt_nr;
+ svr->lsq_penalty += svr->lsq_penalty_per_obj * active_tgt_nr;
+
+ /* Decrease all MDS penalties */
+ list_for_each_entry(svr, &qos->lq_svr_list, lsq_svr_list) {
+ if (svr->lsq_penalty < svr->lsq_penalty_per_obj)
+ svr->lsq_penalty = 0;
+ else
+ svr->lsq_penalty -= svr->lsq_penalty_per_obj;
+ }
+
+ *total_wt = 0;
+ /* Decrease all tgt penalties */
+ ltd_foreach_tgt(ltd, tgt) {
+ if (!tgt->ltd_active)
+ continue;
+
+ if (ltq->ltq_penalty < ltq->ltq_penalty_per_obj)
+ ltq->ltq_penalty = 0;
+ else
+ ltq->ltq_penalty -= ltq->ltq_penalty_per_obj;
+
+ lqos_calc_weight(tgt);
+
+ /* Recalc the total weight of usable osts */
+ if (ltq->ltq_usable)
+ *total_wt += ltq->ltq_weight;
+
+ CDEBUG(D_OTHER, "recalc tgt %d usable=%d avail=%llu"
+ " tgtppo=%llu tgtp=%llu svrppo=%llu"
+ " svrp=%llu wt=%llu\n",
+ tgt->ltd_index, ltq->ltq_usable,
+ tgt_statfs_bavail(tgt) >> 10,
+ ltq->ltq_penalty_per_obj >> 10,
+ ltq->ltq_penalty >> 10,
+ ltq->ltq_svr->lsq_penalty_per_obj >> 10,
+ ltq->ltq_svr->lsq_penalty >> 10,
+ ltq->ltq_weight >> 10);
+ }
+
+ RETURN(0);
+}
+EXPORT_SYMBOL(lqos_recalc_weight);
git://git.whamcloud.com / fs / lustre-release.git / blobdiff