--- /dev/null
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2015 Intel Corporation All Rights Reserved
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation. See file COPYING.
+ *
+ */
+
+#ifdef __KERNEL__
+# include <linux/string.h>
+# include <linux/slab.h>
+# include <linux/bug.h>
+# include <linux/kernel.h>
+# include <linux/crush/crush.h>
+# include <linux/crush/hash.h>
+#else
+# include "crush_compat.h"
+# include "crush.h"
+# include "hash.h"
+#endif
+#include "crush_ln_table.h"
+#include "mapper.h"
+
+#define dprintk(args...) /* printf(args) */
+
+/*
+ * Implement the core CRUSH mapping algorithm.
+ */
+
+/**
+ * crush_find_rule - find a crush_rule id for a given ruleset, type, and size.
+ * @map: the crush_map
+ * @ruleset: the storage ruleset id (user defined)
+ * @type: storage ruleset type (user defined)
+ * @size: output set size
+ */
+int crush_find_rule(const struct crush_map *map, int ruleset, int type, int size)
+{
+ __u32 i;
+
+ for (i = 0; i < map->max_rules; i++) {
+ if (map->rules[i] &&
+ map->rules[i]->mask.ruleset == ruleset &&
+ map->rules[i]->mask.type == type &&
+ map->rules[i]->mask.min_size <= size &&
+ map->rules[i]->mask.max_size >= size)
+ return i;
+ }
+ return -1;
+}
+
+/*
+ * bucket choose methods
+ *
+ * For each bucket algorithm, we have a "choose" method that, given a
+ * crush input @x and replica position (usually, position in output set) @r,
+ * will produce an item in the bucket.
+ */
+
+/*
+ * Choose based on a random permutation of the bucket.
+ *
+ * We used to use some prime number arithmetic to do this, but it
+ * wasn't very random, and had some other bad behaviors. Instead, we
+ * calculate an actual random permutation of the bucket members.
+ * Since this is expensive, we optimize for the r=0 case, which
+ * captures the vast majority of calls.
+ */
+static int bucket_perm_choose(const struct crush_bucket *bucket,
+ struct crush_work_bucket *work,
+ int x, int r)
+{
+ unsigned int pr = r % bucket->size;
+ unsigned int i, s;
+
+ /* start a new permutation if @x has changed */
+ if (work->perm_x != (__u32)x || work->perm_n == 0) {
+ dprintk("bucket %d new x=%d\n", bucket->id, x);
+ work->perm_x = x;
+
+ /* optimize common r=0 case */
+ if (pr == 0) {
+ s = crush_hash32_3(bucket->hash, x, bucket->id, 0) %
+ bucket->size;
+ work->perm[0] = s;
+ work->perm_n = 0xffff; /* magic value, see below */
+ goto out;
+ }
+
+ for (i = 0; i < bucket->size; i++)
+ work->perm[i] = i;
+ work->perm_n = 0;
+ } else if (work->perm_n == 0xffff) {
+ /* clean up after the r=0 case above */
+ for (i = 1; i < bucket->size; i++)
+ work->perm[i] = i;
+ work->perm[work->perm[0]] = 0;
+ work->perm_n = 1;
+ }
+
+ /* calculate permutation up to pr */
+ for (i = 0; i < work->perm_n; i++)
+ dprintk(" perm_choose have %d: %d\n", i, work->perm[i]);
+ while (work->perm_n <= pr) {
+ unsigned int p = work->perm_n;
+ /* no point in swapping the final entry */
+ if (p < bucket->size - 1) {
+ i = crush_hash32_3(bucket->hash, x, bucket->id, p) %
+ (bucket->size - p);
+ if (i) {
+ unsigned int t = work->perm[p + i];
+ work->perm[p + i] = work->perm[p];
+ work->perm[p] = t;
+ }
+ dprintk(" perm_choose swap %d with %d\n", p, p+i);
+ }
+ work->perm_n++;
+ }
+ for (i = 0; i < bucket->size; i++)
+ dprintk(" perm_choose %d: %d\n", i, work->perm[i]);
+
+ s = work->perm[pr];
+out:
+ dprintk(" perm_choose %d sz=%d x=%d r=%d (%d) s=%d\n", bucket->id,
+ bucket->size, x, r, pr, s);
+ return bucket->items[s];
+}
+
+/* uniform */
+static int bucket_uniform_choose(const struct crush_bucket_uniform *bucket,
+ struct crush_work_bucket *work, int x, int r)
+{
+ return bucket_perm_choose(&bucket->h, work, x, r);
+}
+
+/* list */
+static int bucket_list_choose(const struct crush_bucket_list *bucket,
+ int x, int r)
+{
+ int i;
+
+ for (i = bucket->h.size-1; i >= 0; i--) {
+ __u64 w = crush_hash32_4(bucket->h.hash, x, bucket->h.items[i],
+ r, bucket->h.id);
+ w &= 0xffff;
+ dprintk("list_choose i=%d x=%d r=%d item %d weight %x "
+ "sw %x rand %llx",
+ i, x, r, bucket->h.items[i], bucket->item_weights[i],
+ bucket->sum_weights[i], w);
+ w *= bucket->sum_weights[i];
+ w = w >> 16;
+ /*dprintk(" scaled %llx\n", w);*/
+ if (w < bucket->item_weights[i]) {
+ return bucket->h.items[i];
+ }
+ }
+
+ dprintk("bad list sums for bucket %d\n", bucket->h.id);
+ return bucket->h.items[0];
+}
+
+
+/* (binary) tree */
+static int height(int n)
+{
+ int h = 0;
+ while ((n & 1) == 0) {
+ h++;
+ n = n >> 1;
+ }
+ return h;
+}
+
+static int left(int x)
+{
+ int h = height(x);
+ return x - (1 << (h-1));
+}
+
+static int right(int x)
+{
+ int h = height(x);
+ return x + (1 << (h-1));
+}
+
+static int terminal(int x)
+{
+ return x & 1;
+}
+
+static int bucket_tree_choose(const struct crush_bucket_tree *bucket,
+ int x, int r)
+{
+ int n;
+ __u32 w;
+ __u64 t;
+
+ /* start at root */
+ n = bucket->num_nodes >> 1;
+
+ while (!terminal(n)) {
+ int l;
+ /* pick point in [0, w) */
+ w = bucket->node_weights[n];
+ t = (__u64)crush_hash32_4(bucket->h.hash, x, n, r,
+ bucket->h.id) * (__u64)w;
+ t = t >> 32;
+
+ /* descend to the left or right? */
+ l = left(n);
+ if (t < bucket->node_weights[l])
+ n = l;
+ else
+ n = right(n);
+ }
+
+ return bucket->h.items[n >> 1];
+}
+
+
+/* straw */
+
+static int bucket_straw_choose(const struct crush_bucket_straw *bucket,
+ int x, int r)
+{
+ __u32 i;
+ int high = 0;
+ __u64 high_draw = 0;
+ __u64 draw;
+
+ for (i = 0; i < bucket->h.size; i++) {
+ draw = crush_hash32_3(bucket->h.hash, x, bucket->h.items[i], r);
+ draw &= 0xffff;
+ draw *= bucket->straws[i];
+ if (i == 0 || draw > high_draw) {
+ high = i;
+ high_draw = draw;
+ }
+ }
+ return bucket->h.items[high];
+}
+
+/* compute 2^44*log2(input+1) */
+static __u64 crush_ln(unsigned int xin)
+{
+ unsigned int x = xin;
+ int iexpon, index1, index2;
+ __u64 RH, LH, LL, xl64, result;
+
+ x++;
+
+ /* normalize input */
+ iexpon = 15;
+
+ // figure out number of bits we need to shift and
+ // do it in one step instead of iteratively
+ if (!(x & 0x18000)) {
+ int bits = __builtin_clz(x & 0x1FFFF) - 16;
+ x <<= bits;
+ iexpon = 15 - bits;
+ }
+
+ index1 = (x >> 8) << 1;
+ /* RH ~ 2^56/index1 */
+ RH = __RH_LH_tbl[index1 - 256];
+ /* LH ~ 2^48 * log2(index1/256) */
+ LH = __RH_LH_tbl[index1 + 1 - 256];
+
+ /* RH*x ~ 2^48 * (2^15 + xf), xf<2^8 */
+ xl64 = (__s64)x * RH;
+ xl64 >>= 48;
+
+ result = iexpon;
+ result <<= (12 + 32);
+
+ index2 = xl64 & 0xff;
+ /* LL ~ 2^48*log2(1.0+index2/2^15) */
+ LL = __LL_tbl[index2];
+
+ LH = LH + LL;
+
+ LH >>= (48 - 12 - 32);
+ result += LH;
+
+ return result;
+}
+
+
+/*
+ * straw2
+ *
+ * for reference, see:
+ *
+ * http://en.wikipedia.org/wiki/Exponential_distribution#Distribution_of_the_minimum_of_exponential_random_variables
+ *
+ */
+
+static inline __u32 *get_choose_arg_weights(const struct crush_bucket_straw2 *bucket,
+ const struct crush_choose_arg *arg,
+ int position)
+{
+ if ((arg == NULL) ||
+ (arg->weight_set == NULL))
+ return bucket->item_weights;
+ if (position >= arg->weight_set_size)
+ position = arg->weight_set_size - 1;
+ return arg->weight_set[position].weights;
+}
+
+static inline __s32 *get_choose_arg_ids(const struct crush_bucket_straw2 *bucket,
+ const struct crush_choose_arg *arg)
+{
+ if ((arg == NULL) || (arg->ids == NULL))
+ return bucket->h.items;
+ return arg->ids;
+}
+
+static int bucket_straw2_choose(const struct crush_bucket_straw2 *bucket,
+ int x, int r, const struct crush_choose_arg *arg,
+ int position)
+{
+ unsigned int i, high = 0;
+ unsigned int u;
+ __s64 ln, draw, high_draw = 0;
+ __u32 *weights = get_choose_arg_weights(bucket, arg, position);
+ __s32 *ids = get_choose_arg_ids(bucket, arg);
+ for (i = 0; i < bucket->h.size; i++) {
+ dprintk("weight 0x%x item %d\n", weights[i], ids[i]);
+ if (weights[i]) {
+ u = crush_hash32_3(bucket->h.hash, x, ids[i], r);
+ u &= 0xffff;
+
+ /*
+ * for some reason slightly less than 0x10000 produces
+ * a slightly more accurate distribution... probably a
+ * rounding effect.
+ *
+ * the natural log lookup table maps [0,0xffff]
+ * (corresponding to real numbers [1/0x10000, 1] to
+ * [0, 0xffffffffffff] (corresponding to real numbers
+ * [-11.090355,0]).
+ */
+ ln = crush_ln(u) - 0x1000000000000ll;
+
+ /*
+ * divide by 16.16 fixed-point weight. note
+ * that the ln value is negative, so a larger
+ * weight means a larger (less negative) value
+ * for draw.
+ */
+ draw = div64_s64(ln, weights[i]);
+ } else {
+ draw = S64_MIN;
+ }
+
+ if (i == 0 || draw > high_draw) {
+ high = i;
+ high_draw = draw;
+ }
+ }
+
+ return bucket->h.items[high];
+}
+
+
+static int crush_bucket_choose(const struct crush_bucket *in,
+ struct crush_work_bucket *work,
+ int x, int r,
+ const struct crush_choose_arg *arg,
+ int position)
+{
+ dprintk(" crush_bucket_choose %d x=%d r=%d\n", in->id, x, r);
+ BUG_ON(in->size == 0);
+ switch (in->alg) {
+ case CRUSH_BUCKET_UNIFORM:
+ return bucket_uniform_choose(
+ (const struct crush_bucket_uniform *)in,
+ work, x, r);
+ case CRUSH_BUCKET_LIST:
+ return bucket_list_choose((const struct crush_bucket_list *)in,
+ x, r);
+ case CRUSH_BUCKET_TREE:
+ return bucket_tree_choose((const struct crush_bucket_tree *)in,
+ x, r);
+ case CRUSH_BUCKET_STRAW:
+ return bucket_straw_choose(
+ (const struct crush_bucket_straw *)in,
+ x, r);
+ case CRUSH_BUCKET_STRAW2:
+ return bucket_straw2_choose(
+ (const struct crush_bucket_straw2 *)in,
+ x, r, arg, position);
+ default:
+ dprintk("unknown bucket %d alg %d\n", in->id, in->alg);
+ return in->items[0];
+ }
+}
+
+/*
+ * true if device is marked "out" (failed, fully offloaded)
+ * of the cluster
+ */
+static int is_out(const struct crush_map *map,
+ const __u32 *weight, int weight_max,
+ int item, int x)
+{
+ if (item >= weight_max)
+ return 1;
+ if (weight[item] >= 0x10000)
+ return 0;
+ if (weight[item] == 0)
+ return 1;
+ if ((crush_hash32_2(CRUSH_HASH_RJENKINS1, x, item) & 0xffff)
+ < weight[item])
+ return 0;
+ return 1;
+}
+
+/**
+ * crush_choose_firstn - choose numrep distinct items of given type
+ * @map: the crush_map
+ * @bucket: the bucket we are choose an item from
+ * @x: crush input value
+ * @numrep: the number of items to choose
+ * @type: the type of item to choose
+ * @out: pointer to output vector
+ * @outpos: our position in that vector
+ * @out_size: size of the out vector
+ * @tries: number of attempts to make
+ * @recurse_tries: number of attempts to have recursive chooseleaf make
+ * @local_retries: localized retries
+ * @local_fallback_retries: localized fallback retries
+ * @recurse_to_leaf: true if we want one device under each item of given type (chooseleaf instead of choose)
+ * @stable: stable mode starts rep=0 in the recursive call for all replicas
+ * @vary_r: pass r to recursive calls
+ * @out2: second output vector for leaf items (if @recurse_to_leaf)
+ * @parent_r: r value passed from the parent
+ */
+static int crush_choose_firstn(const struct crush_map *map,
+ struct crush_work *work,
+ const struct crush_bucket *bucket,
+ const __u32 *weight, int weight_max,
+ int x, int numrep, int type,
+ int *out, int outpos,
+ int out_size,
+ unsigned int tries,
+ unsigned int recurse_tries,
+ unsigned int local_retries,
+ unsigned int local_fallback_retries,
+ int recurse_to_leaf,
+ unsigned int vary_r,
+ unsigned int stable,
+ int *out2,
+ int parent_r,
+ const struct crush_choose_arg *choose_args)
+{
+ int rep;
+ unsigned int ftotal, flocal;
+ int retry_descent, retry_bucket, skip_rep;
+ const struct crush_bucket *in = bucket;
+ int r;
+ int i;
+ int item = 0;
+ int itemtype;
+ int collide, reject;
+ int count = out_size;
+
+ dprintk("CHOOSE%s bucket %d x %d outpos %d numrep %d tries %d \
+recurse_tries %d local_retries %d local_fallback_retries %d \
+parent_r %d stable %d\n",
+ recurse_to_leaf ? "_LEAF" : "",
+ bucket->id, x, outpos, numrep,
+ tries, recurse_tries, local_retries, local_fallback_retries,
+ parent_r, stable);
+
+ for (rep = stable ? 0 : outpos; rep < numrep && count > 0 ; rep++) {
+ /* keep trying until we get a non-out, non-colliding item */
+ ftotal = 0;
+ skip_rep = 0;
+ do {
+ retry_descent = 0;
+ in = bucket; /* initial bucket */
+
+ /* choose through intervening buckets */
+ flocal = 0;
+ do {
+ collide = 0;
+ retry_bucket = 0;
+ r = rep + parent_r;
+ /* r' = r + f_total */
+ r += ftotal;
+
+ /* bucket choose */
+ if (in->size == 0) {
+ reject = 1;
+ goto reject;
+ }
+ if (local_fallback_retries > 0 &&
+ flocal >= (in->size>>1) &&
+ flocal > local_fallback_retries)
+ item = bucket_perm_choose(
+ in, work->work[-1-in->id],
+ x, r);
+ else
+ item = crush_bucket_choose(
+ in, work->work[-1-in->id],
+ x, r,
+ (choose_args ? &choose_args[-1-in->id] : 0),
+ outpos);
+ if (item >= map->max_devices) {
+ dprintk(" bad item %d\n", item);
+ skip_rep = 1;
+ break;
+ }
+
+ /* desired type? */
+ if (item < 0)
+ itemtype = map->buckets[-1-item]->type;
+ else
+ itemtype = 0;
+ dprintk(" item %d type %d\n", item, itemtype);
+
+ /* keep going? */
+ if (itemtype != type) {
+ if (item >= 0 ||
+ (-1-item) >= map->max_buckets) {
+ dprintk(" bad item type %d\n", type);
+ skip_rep = 1;
+ break;
+ }
+ in = map->buckets[-1-item];
+ retry_bucket = 1;
+ continue;
+ }
+
+ /* collision? */
+ for (i = 0; i < outpos; i++) {
+ if (out[i] == item) {
+ collide = 1;
+ break;
+ }
+ }
+
+ reject = 0;
+ if (!collide && recurse_to_leaf) {
+ if (item < 0) {
+ int sub_r;
+ if (vary_r)
+ sub_r = r >> (vary_r-1);
+ else
+ sub_r = 0;
+ if (crush_choose_firstn(
+ map,
+ work,
+ map->buckets[-1-item],
+ weight, weight_max,
+ x, stable ? 1 : outpos+1, 0,
+ out2, outpos, count,
+ recurse_tries, 0,
+ local_retries,
+ local_fallback_retries,
+ 0,
+ vary_r,
+ stable,
+ NULL,
+ sub_r,
+ choose_args) <= outpos)
+ /* didn't get leaf */
+ reject = 1;
+ } else {
+ /* we already have a leaf! */
+ out2[outpos] = item;
+ }
+ }
+
+ if (!reject && !collide) {
+ /* out? */
+ if (itemtype == 0)
+ reject = is_out(map, weight,
+ weight_max,
+ item, x);
+ }
+
+reject:
+ if (reject || collide) {
+ ftotal++;
+ flocal++;
+
+ if (collide && flocal <= local_retries)
+ /* retry locally a few times */
+ retry_bucket = 1;
+ else if (local_fallback_retries > 0 &&
+ flocal <= in->size + local_fallback_retries)
+ /* exhaustive bucket search */
+ retry_bucket = 1;
+ else if (ftotal < tries)
+ /* then retry descent */
+ retry_descent = 1;
+ else
+ /* else give up */
+ skip_rep = 1;
+ dprintk(" reject %d collide %d "
+ "ftotal %u flocal %u\n",
+ reject, collide, ftotal,
+ flocal);
+ }
+ } while (retry_bucket);
+ } while (retry_descent);
+
+ if (skip_rep) {
+ dprintk("skip rep\n");
+ continue;
+ }
+
+ dprintk("CHOOSE got %d\n", item);
+ out[outpos] = item;
+ outpos++;
+ count--;
+#ifndef __KERNEL__
+ if (map->choose_tries && ftotal <= map->choose_total_tries)
+ map->choose_tries[ftotal]++;
+#endif
+ }
+
+ dprintk("CHOOSE returns %d\n", outpos);
+ return outpos;
+}
+
+
+/**
+ * crush_choose_indep: alternative breadth-first positionally stable mapping
+ *
+ */
+static void crush_choose_indep(const struct crush_map *map,
+ struct crush_work *work,
+ const struct crush_bucket *bucket,
+ const __u32 *weight, int weight_max,
+ int x, int left, int numrep, int type,
+ int *out, int outpos,
+ unsigned int tries,
+ unsigned int recurse_tries,
+ int recurse_to_leaf,
+ int *out2,
+ int parent_r,
+ const struct crush_choose_arg *choose_args)
+{
+ const struct crush_bucket *in = bucket;
+ int endpos = outpos + left;
+ int rep;
+ unsigned int ftotal;
+ int r;
+ int i;
+ int item = 0;
+ int itemtype;
+ int collide;
+
+ dprintk("CHOOSE%s INDEP bucket %d x %d outpos %d numrep %d\n", recurse_to_leaf ? "_LEAF" : "",
+ bucket->id, x, outpos, numrep);
+
+ /* initially my result is undefined */
+ for (rep = outpos; rep < endpos; rep++) {
+ out[rep] = CRUSH_ITEM_UNDEF;
+ if (out2)
+ out2[rep] = CRUSH_ITEM_UNDEF;
+ }
+
+ for (ftotal = 0; left > 0 && ftotal < tries; ftotal++) {
+#ifdef DEBUG_INDEP
+ if (out2 && ftotal) {
+ dprintk("%u %d a: ", ftotal, left);
+ for (rep = outpos; rep < endpos; rep++) {
+ dprintk(" %d", out[rep]);
+ }
+ dprintk("\n");
+ dprintk("%u %d b: ", ftotal, left);
+ for (rep = outpos; rep < endpos; rep++) {
+ dprintk(" %d", out2[rep]);
+ }
+ dprintk("\n");
+ }
+#endif
+ for (rep = outpos; rep < endpos; rep++) {
+ if (out[rep] != CRUSH_ITEM_UNDEF)
+ continue;
+
+ in = bucket; /* initial bucket */
+
+ /* choose through intervening buckets */
+ for (;;) {
+ /* note: we base the choice on the position
+ * even in the nested call. that means that
+ * if the first layer chooses the same bucket
+ * in a different position, we will tend to
+ * choose a different item in that bucket.
+ * this will involve more devices in data
+ * movement and tend to distribute the load.
+ */
+ r = rep + parent_r;
+
+ /* be careful */
+ if (in->alg == CRUSH_BUCKET_UNIFORM &&
+ in->size % numrep == 0)
+ /* r'=r+(n+1)*f_total */
+ r += (numrep+1) * ftotal;
+ else
+ /* r' = r + n*f_total */
+ r += numrep * ftotal;
+
+ /* bucket choose */
+ if (in->size == 0) {
+ dprintk(" empty bucket\n");
+ break;
+ }
+
+ item = crush_bucket_choose(
+ in, work->work[-1-in->id],
+ x, r,
+ (choose_args ? &choose_args[-1-in->id] : 0),
+ outpos);
+ if (item >= map->max_devices) {
+ dprintk(" bad item %d\n", item);
+ out[rep] = CRUSH_ITEM_NONE;
+ if (out2)
+ out2[rep] = CRUSH_ITEM_NONE;
+ left--;
+ break;
+ }
+
+ /* desired type? */
+ if (item < 0)
+ itemtype = map->buckets[-1-item]->type;
+ else
+ itemtype = 0;
+ dprintk(" item %d type %d\n", item, itemtype);
+
+ /* keep going? */
+ if (itemtype != type) {
+ if (item >= 0 ||
+ (-1-item) >= map->max_buckets) {
+ dprintk(" bad item type %d\n", type);
+ out[rep] = CRUSH_ITEM_NONE;
+ if (out2)
+ out2[rep] =
+ CRUSH_ITEM_NONE;
+ left--;
+ break;
+ }
+ in = map->buckets[-1-item];
+ continue;
+ }
+
+ /* collision? */
+ collide = 0;
+ for (i = outpos; i < endpos; i++) {
+ if (out[i] == item) {
+ collide = 1;
+ break;
+ }
+ }
+ if (collide)
+ break;
+
+ if (recurse_to_leaf) {
+ if (item < 0) {
+ crush_choose_indep(
+ map,
+ work,
+ map->buckets[-1-item],
+ weight, weight_max,
+ x, 1, numrep, 0,
+ out2, rep,
+ recurse_tries, 0,
+ 0, NULL, r, choose_args);
+ if (out2[rep] == CRUSH_ITEM_NONE) {
+ /* placed nothing; no leaf */
+ break;
+ }
+ } else {
+ /* we already have a leaf! */
+ out2[rep] = item;
+ }
+ }
+
+ /* out? */
+ if (itemtype == 0 &&
+ is_out(map, weight, weight_max, item, x))
+ break;
+
+ /* yay! */
+ out[rep] = item;
+ left--;
+ break;
+ }
+ }
+ }
+ for (rep = outpos; rep < endpos; rep++) {
+ if (out[rep] == CRUSH_ITEM_UNDEF) {
+ out[rep] = CRUSH_ITEM_NONE;
+ }
+ if (out2 && out2[rep] == CRUSH_ITEM_UNDEF) {
+ out2[rep] = CRUSH_ITEM_NONE;
+ }
+ }
+#ifndef __KERNEL__
+ if (map->choose_tries && ftotal <= map->choose_total_tries)
+ map->choose_tries[ftotal]++;
+#endif
+#ifdef DEBUG_INDEP
+ if (out2) {
+ dprintk("%u %d a: ", ftotal, left);
+ for (rep = outpos; rep < endpos; rep++) {
+ dprintk(" %d", out[rep]);
+ }
+ dprintk("\n");
+ dprintk("%u %d b: ", ftotal, left);
+ for (rep = outpos; rep < endpos; rep++) {
+ dprintk(" %d", out2[rep]);
+ }
+ dprintk("\n");
+ }
+#endif
+}
+
+
+/* This takes a chunk of memory and sets it up to be a shiny new
+ working area for a CRUSH placement computation. It must be called
+ on any newly allocated memory before passing it in to
+ crush_do_rule. It may be used repeatedly after that, so long as the
+ map has not changed. If the map /has/ changed, you must make sure
+ the working size is no smaller than what was allocated and re-run
+ crush_init_workspace.
+
+ If you do retain the working space between calls to crush, make it
+ thread-local. If you reinstitute the locking I've spent so much
+ time getting rid of, I will be very unhappy with you. */
+
+void crush_init_workspace(const struct crush_map *m, void *v) {
+ /* We work by moving through the available space and setting
+ values and pointers as we go.
+
+ It's a bit like Forth's use of the 'allot' word since we
+ set the pointer first and then reserve the space for it to
+ point to by incrementing the point. */
+ struct crush_work *w = (struct crush_work *)v;
+ char *point = (char *)v;
+ __s32 b;
+ point += sizeof(struct crush_work);
+ w->work = (struct crush_work_bucket **)point;
+ point += m->max_buckets * sizeof(struct crush_work_bucket *);
+ for (b = 0; b < m->max_buckets; ++b) {
+ if (m->buckets[b] == 0)
+ continue;
+
+ w->work[b] = (struct crush_work_bucket *) point;
+ switch (m->buckets[b]->alg) {
+ default:
+ point += sizeof(struct crush_work_bucket);
+ break;
+ }
+ w->work[b]->perm_x = 0;
+ w->work[b]->perm_n = 0;
+ w->work[b]->perm = (__u32 *)point;
+ point += m->buckets[b]->size * sizeof(__u32);
+ }
+ BUG_ON((char *)point - (char *)w != m->working_size);
+}
+
+/**
+ * crush_do_rule - calculate a mapping with the given input and rule
+ * @map: the crush_map
+ * @ruleno: the rule id
+ * @x: hash input
+ * @result: pointer to result vector
+ * @result_max: maximum result size
+ * @weight: weight vector (for map leaves)
+ * @weight_max: size of weight vector
+ * @cwin: Pointer to at least map->working_size bytes of memory or NULL.
+ */
+int crush_do_rule(const struct crush_map *map,
+ int ruleno, int x, int *result, int result_max,
+ const __u32 *weight, int weight_max,
+ void *cwin, const struct crush_choose_arg *choose_args)
+{
+ int result_len;
+ struct crush_work *cw = cwin;
+ int *a = (int *)((char *)cw + map->working_size);
+ int *b = a + result_max;
+ int *c = b + result_max;
+ int *w = a;
+ int *o = b;
+ int recurse_to_leaf;
+ int wsize = 0;
+ int osize;
+ int *tmp;
+ const struct crush_rule *rule;
+ __u32 step;
+ int i, j;
+ int numrep;
+ int out_size;
+ /*
+ * the original choose_total_tries value was off by one (it
+ * counted "retries" and not "tries"). add one.
+ */
+ int choose_tries = map->choose_total_tries + 1;
+ int choose_leaf_tries = 0;
+ /*
+ * the local tries values were counted as "retries", though,
+ * and need no adjustment
+ */
+ int choose_local_retries = map->choose_local_tries;
+ int choose_local_fallback_retries = map->choose_local_fallback_tries;
+
+ int vary_r = map->chooseleaf_vary_r;
+ int stable = map->chooseleaf_stable;
+
+ if ((__u32)ruleno >= map->max_rules) {
+ dprintk(" bad ruleno %d\n", ruleno);
+ return 0;
+ }
+
+ rule = map->rules[ruleno];
+ result_len = 0;
+
+ for (step = 0; step < rule->len; step++) {
+ int firstn = 0;
+ const struct crush_rule_step *curstep = &rule->steps[step];
+
+ switch (curstep->op) {
+ case CRUSH_RULE_TAKE:
+ if ((curstep->arg1 >= 0 &&
+ curstep->arg1 < map->max_devices) ||
+ (-1-curstep->arg1 >= 0 &&
+ -1-curstep->arg1 < map->max_buckets &&
+ map->buckets[-1-curstep->arg1])) {
+ w[0] = curstep->arg1;
+ wsize = 1;
+ } else {
+ dprintk(" bad take value %d\n", curstep->arg1);
+ }
+ break;
+
+ case CRUSH_RULE_SET_CHOOSE_TRIES:
+ if (curstep->arg1 > 0)
+ choose_tries = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_SET_CHOOSELEAF_TRIES:
+ if (curstep->arg1 > 0)
+ choose_leaf_tries = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_SET_CHOOSE_LOCAL_TRIES:
+ if (curstep->arg1 >= 0)
+ choose_local_retries = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_SET_CHOOSE_LOCAL_FALLBACK_TRIES:
+ if (curstep->arg1 >= 0)
+ choose_local_fallback_retries = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_SET_CHOOSELEAF_VARY_R:
+ if (curstep->arg1 >= 0)
+ vary_r = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_SET_CHOOSELEAF_STABLE:
+ if (curstep->arg1 >= 0)
+ stable = curstep->arg1;
+ break;
+
+ case CRUSH_RULE_CHOOSELEAF_FIRSTN:
+ case CRUSH_RULE_CHOOSE_FIRSTN:
+ firstn = 1;
+ /* fall through */
+ case CRUSH_RULE_CHOOSELEAF_INDEP:
+ case CRUSH_RULE_CHOOSE_INDEP:
+ if (wsize == 0)
+ break;
+
+ recurse_to_leaf =
+ curstep->op ==
+ CRUSH_RULE_CHOOSELEAF_FIRSTN ||
+ curstep->op ==
+ CRUSH_RULE_CHOOSELEAF_INDEP;
+
+ /* reset output */
+ osize = 0;
+
+ for (i = 0; i < wsize; i++) {
+ int bno;
+ numrep = curstep->arg1;
+ if (numrep <= 0) {
+ numrep += result_max;
+ if (numrep <= 0)
+ continue;
+ }
+ j = 0;
+ /* make sure bucket id is valid */
+ bno = -1 - w[i];
+ if (bno < 0 || bno >= map->max_buckets) {
+ // w[i] is probably CRUSH_ITEM_NONE
+ dprintk(" bad w[i] %d\n", w[i]);
+ continue;
+ }
+ if (firstn) {
+ int recurse_tries;
+ if (choose_leaf_tries)
+ recurse_tries =
+ choose_leaf_tries;
+ else if (map->chooseleaf_descend_once)
+ recurse_tries = 1;
+ else
+ recurse_tries = choose_tries;
+ osize += crush_choose_firstn(
+ map,
+ cw,
+ map->buckets[bno],
+ weight, weight_max,
+ x, numrep,
+ curstep->arg2,
+ o+osize, j,
+ result_max-osize,
+ choose_tries,
+ recurse_tries,
+ choose_local_retries,
+ choose_local_fallback_retries,
+ recurse_to_leaf,
+ vary_r,
+ stable,
+ c+osize,
+ 0,
+ choose_args);
+ } else {
+ out_size = ((numrep < (result_max-osize)) ?
+ numrep : (result_max-osize));
+ crush_choose_indep(
+ map,
+ cw,
+ map->buckets[bno],
+ weight, weight_max,
+ x, out_size, numrep,
+ curstep->arg2,
+ o+osize, j,
+ choose_tries,
+ choose_leaf_tries ?
+ choose_leaf_tries : 1,
+ recurse_to_leaf,
+ c+osize,
+ 0,
+ choose_args);
+ osize += out_size;
+ }
+ }
+
+ if (recurse_to_leaf)
+ /* copy final _leaf_ values to output set */
+ memcpy(o, c, osize*sizeof(*o));
+
+ /* swap o and w arrays */
+ tmp = o;
+ o = w;
+ w = tmp;
+ wsize = osize;
+ break;
+
+
+ case CRUSH_RULE_EMIT:
+ for (i = 0; i < wsize && result_len < result_max; i++) {
+ result[result_len] = w[i];
+ result_len++;
+ }
+ wsize = 0;
+ break;
+
+ default:
+ dprintk(" unknown op %d at step %d\n",
+ curstep->op, step);
+ break;
+ }
+ }
+
+ return result_len;
+}
Code Review / stor4nfv.git / blobdiff