#include <sys/time.h>
#include <errno.h>
#include <signal.h>
+#include <assert.h>
#define STRINGIFY2(x) #x
#define STRINGIFY(x) STRINGIFY2(x)
union {
int flag; /* open and store */
struct traverse *trav; /* traverse start */
- TDB_DATA pre_append; /* append */
+ struct { /* append */
+ TDB_DATA pre;
+ TDB_DATA post;
+ } append;
unsigned int transaction_end; /* transaction start */
};
};
static void op_add_append(const char *filename,
struct op op[], unsigned int op_num, char *words[])
{
- TDB_DATA post_append;
-
if (!words[2] || !words[3] || !words[4] || !words[5] || words[6]
|| !streq(words[4], "="))
fail(filename, op_num+1, "Expect <key> <data> = <rec>");
op[op_num].key = make_tdb_data(op, filename, op_num+1, words[2]);
op[op_num].data = make_tdb_data(op, filename, op_num+1, words[3]);
- post_append = make_tdb_data(op, filename, op_num+1, words[5]);
+ op[op_num].append.post
+ = make_tdb_data(op, filename, op_num+1, words[5]);
/* By subtraction, figure out what previous data was. */
- op[op_num].pre_append.dptr = post_append.dptr;
- op[op_num].pre_append.dsize = post_append.dsize - op[op_num].data.dsize;
+ op[op_num].append.pre.dptr = op[op_num].append.post.dptr;
+ op[op_num].append.pre.dsize
+ = op[op_num].append.post.dsize - op[op_num].data.dsize;
total_keys++;
}
struct depend {
/* We can have more than one */
- struct list_node list;
- unsigned int file;
- unsigned int op;
-};
-
-struct depend_xmit {
- unsigned int dst_op;
- unsigned int src_file, src_op;
+ struct list_node pre_list;
+ struct list_node post_list;
+ unsigned int needs_file;
+ unsigned int needs_opnum;
+ unsigned int satisfies_file;
+ unsigned int satisfies_opnum;
};
-static void remove_matching_dep(struct list_head *deps,
- unsigned int file, unsigned int op)
-{
- struct depend *dep;
-
- list_for_each(deps, dep, list) {
- if (dep->file == file && dep->op == op) {
- list_del(&dep->list);
- return;
- }
- }
- errx(1, "Failed to find depend on file %u line %u\n", file, op+1);
-}
-
static void check_deps(const char *filename, struct op op[], unsigned int num)
{
#ifdef DEBUG_DEPS
struct depend *dep;
printf("%s:%u still waiting for:\n", filename[file], i+1);
- list_for_each(&op[i].pre, dep, list)
- printf(" %s:%u\n", filename[dep->file], dep->op+1);
+ list_for_each(&op[i].pre, dep, pre_list)
+ printf(" %s:%u\n",
+ filename[dep->satisfies_file], dep->satisfies_opnum+1);
check_deps(filename[file], op, i);
}
+/* We simply read/write pointers, since we all are children. */
static void do_pre(char *filename[], unsigned int file, int pre_fd,
struct op op[], unsigned int i)
{
while (!list_empty(&op[i].pre)) {
- struct depend_xmit dep;
+ struct depend *dep;
#if DEBUG_DEPS
printf("%s:%u:waiting for pre\n", filename[file], i+1);
#if DEBUG_DEPS
printf("%s:%u:got pre %u from %s:%u\n", filename[file], i+1,
- dep.dst_op+1, filename[dep.src_file], dep.src_op+1);
+ dep->needs_op, dep->satisfies_file, dep->satisfies_op+1);
fflush(stdout);
#endif
/* This could be any op, not just this one. */
- remove_matching_dep(&op[dep.dst_op].pre,
- dep.src_file, dep.src_op);
+ talloc_free(dep);
}
}
{
struct depend *dep;
- list_for_each(&op[i].post, dep, list) {
- struct depend_xmit dx;
-
- dx.src_file = file;
- dx.src_op = i;
- dx.dst_op = dep->op;
+ list_for_each(&op[i].post, dep, post_list) {
#if DEBUG_DEPS
printf("%s:%u:sending to file %s:%u\n", filename[file], i+1,
- filename[dep->file], dep->op+1);
+ filename[dep->needs_file], dep->needs_opnum+1);
#endif
- if (write(pipes[dep->file].fd[1], &dx, sizeof(dx))
- != sizeof(dx))
+ if (write(pipes[dep->needs_file].fd[1], &dep, sizeof(dep))
+ != sizeof(dep))
err(1, "%s:%u failed to tell file %s",
- filename[file], i+1, filename[dep->file]);
+ filename[file], i+1, filename[dep->needs_file]);
}
}
break;
case OP_TDB_STORE:
try(tdb_store(tdb, op[i].key, op[i].data, op[i].flag),
- op[i].ret < 0 ? op[i].ret : 0);
+ op[i].ret);
break;
case OP_TDB_APPEND:
- try(tdb_append(tdb, op[i].key, op[i].data),
- op[i].ret < 0 ? op[i].ret : 0);
+ try(tdb_append(tdb, op[i].key, op[i].data), op[i].ret);
break;
case OP_TDB_GET_SEQNUM:
try(tdb_get_seqnum(tdb), op[i].ret);
return NULL;
case OP_TDB_APPEND:
- if (op->pre_append.dsize == 0)
+ if (op->append.pre.dsize == 0)
return ¬_exists_or_empty;
- return &op->pre_append;
+ return &op->append.pre;
case OP_TDB_STORE:
if (op->flag == TDB_INSERT) {
}
-enum satisfaction {
- /* This op makes the other one possible. */
- SATISFIES,
- /* This op makes the other one impossible. */
- DISSATISFIES,
- /* This op makes no difference. */
- NO_CHANGE
-};
-
-static enum satisfaction satisfies(const struct op *op, const TDB_DATA *need)
+/* What's the data after this op? pre if nothing changed. */
+static const TDB_DATA *gives(const struct op *op, const TDB_DATA *pre)
{
- bool deletes, creates;
-
/* Failed ops don't change state of db. */
if (op->ret < 0)
- return NO_CHANGE;
-
- deletes = (op->op == OP_TDB_DELETE || op->op == OP_TDB_WIPE_ALL);
- /* Append/store is creating the record if ret == 0 (1 means replaced) */
- if (op->op == OP_TDB_APPEND || op->op == OP_TDB_STORE)
- creates = (op->ret == 0);
- else
- creates = false;
-
- if (need == &must_not_exist) {
- if (deletes)
- return SATISFIES;
- if (creates)
- return DISSATISFIES;
- return NO_CHANGE;
- }
+ return pre;
- if (need == &must_exist) {
- if (deletes)
- return DISSATISFIES;
- if (creates)
- return SATISFIES;
- return NO_CHANGE;
- }
+ if (op->op == OP_TDB_DELETE || op->op == OP_TDB_WIPE_ALL)
+ return &tdb_null;
- if (need == ¬_exists_or_empty) {
- if (deletes)
- return SATISFIES;
- if (!creates)
- return NO_CHANGE;
- }
+ if (op->op == OP_TDB_APPEND)
+ return &op->append.post;
- /* OK, we need an exact match. */
- if (deletes)
- return DISSATISFIES;
-
- /* An append which results in the wrong data dissatisfies. */
- if (op->op == OP_TDB_APPEND) {
- if (op->pre_append.dsize + op->data.dsize != need->dsize)
- return DISSATISFIES;
- if (memcmp(op->pre_append.dptr, need->dptr,
- op->pre_append.dsize) != 0)
- return DISSATISFIES;
- if (memcmp(op->data.dptr, need->dptr + op->pre_append.dsize,
- op->data.dsize) != 0)
- return DISSATISFIES;
- return SATISFIES;
- } else if (op->op == OP_TDB_STORE) {
- if (key_eq(op->data, *need))
- return SATISFIES;
- return DISSATISFIES;
- }
- return NO_CHANGE;
+ if (op->op == OP_TDB_STORE)
+ return &op->data;
+
+ return pre;
}
static struct keyinfo *hash_ops(struct op *op[], unsigned int num_ops[],
unsigned int i, j, h;
struct keyinfo *hash;
- /* Gcc nexted function extension. How cool is this? */
- int compare_user_serial(const void *_a, const void *_b)
- {
- const struct key_user *a = _a, *b = _b;
- int ret = op[a->file][a->op_num].serial
- - op[b->file][b->op_num].serial;
-
- /* Serial is not completely reliable. First, fetches don't
- * inc serial, second we don't lock to get seq number.
- * This smooths things a little for simple cases. */
- if (ret == 0) {
- const TDB_DATA *a_needs, *b_needs;
-
- b_needs = needs(&op[b->file][b->op_num]);
- switch (satisfies(&op[a->file][a->op_num], b_needs)) {
- case SATISFIES:
- /* A comes first: it satisfies B. */
- return -1;
- case DISSATISFIES:
- /* A doesn't come first: it messes up B. */
- return 1;
- default:
- break;
- }
-
- a_needs = needs(&op[a->file][a->op_num]);
- switch (satisfies(&op[b->file][b->op_num], a_needs)) {
- case SATISFIES:
- /* B comes first: it satisfies A. */
- return 1;
- case DISSATISFIES:
- /* B doesn't come first: it messes up A. */
- return -1;
- default:
- break;
- }
- }
- return ret;
- }
-
hash = talloc_zero_array(op[0], struct keyinfo, total_keys*2);
for (i = 0; i < num; i++) {
for (j = 1; j < num_ops[i]; j++) {
}
}
- /* Now sort into seqnum order. */
- for (h = 0; h < total_keys * 2; h++)
- qsort(hash[h].user, hash[h].num_users, sizeof(hash[h].user[0]),
- compare_user_serial);
-
return hash;
}
+static bool satisfies(const TDB_DATA *data, const TDB_DATA *need)
+{
+ /* Don't need anything? Cool. */
+ if (!need)
+ return true;
+
+ /* This should be tdb_null or a real value. */
+ assert(data != &must_exist);
+ assert(data != &must_not_exist);
+ assert(data != ¬_exists_or_empty);
+
+ /* must_not_exist == must_not_exist, must_exist == must_exist, or
+ not_exists_or_empty == not_exists_or_empty. */
+ if (data->dsize == need->dsize && data->dptr == need->dptr)
+ return true;
+
+ /* Must not exist? data must not exist. */
+ if (need == &must_not_exist)
+ return data->dptr == NULL;
+
+ /* Must exist? */
+ if (need == &must_exist)
+ return data->dptr != NULL;
+
+ /* Either noexist or empty. */
+ if (need == ¬_exists_or_empty)
+ return data->dsize == 0;
+
+ /* Needs something specific. */
+ return key_eq(*data, *need);
+}
+
+static void move_to_front(struct key_user res[], unsigned int elem)
+{
+ if (elem != 0) {
+ struct key_user tmp = res[elem];
+ memmove(res + 1, res, elem*sizeof(res[0]));
+ res[0] = tmp;
+ }
+}
+
+static void restore_to_pos(struct key_user res[], unsigned int elem)
+{
+ if (elem != 0) {
+ struct key_user tmp = res[0];
+ memmove(res, res + 1, elem*sizeof(res[0]));
+ res[elem] = tmp;
+ }
+}
+
+static bool sort_deps(char *filename[], struct op *op[],
+ struct key_user res[], unsigned num,
+ const TDB_DATA *data, unsigned num_files)
+{
+ unsigned int i, files_done;
+ struct op *this_op;
+ bool done[num_files];
+
+ /* Nothing left? We're sorted. */
+ if (num == 0)
+ return true;
+
+ memset(done, 0, sizeof(done));
+
+ /* Since ops within a trace file are ordered, we just need to figure
+ * out which file to try next. Since we don't take into account
+ * inter-key relationships (which exist by virtue of trace file order),
+ * we minimize the chance of harm by trying to keep in serial order. */
+ for (files_done = 0, i = 0; i < num && files_done < num_files; i++) {
+ if (done[res[i].file])
+ continue;
+
+ this_op = &op[res[i].file][res[i].op_num];
+ /* Is what we have good enough for this op? */
+ if (satisfies(data, needs(this_op))) {
+ move_to_front(res, i);
+ if (sort_deps(filename, op, res+1, num-1,
+ gives(this_op, data), num_files))
+ return true;
+ restore_to_pos(res, i);
+ }
+ done[res[i].file] = true;
+ files_done++;
+ }
+
+ /* No combination worked. */
+ return false;
+}
+
+static void check_dep_sorting(struct key_user user[], unsigned num_users,
+ unsigned num_files)
+{
+#if DEBUG_DEPS
+ unsigned int i;
+ unsigned minima[num_files];
+
+ memset(minima, 0, sizeof(minima));
+ for (i = 0; i < num_users; i++) {
+ assert(minima[user[i].file] < user[i].op_num);
+ minima[user[i].file] = user[i].op_num;
+ }
+#endif
+}
+
+/* All these ops have the same serial number. Which comes first?
+ *
+ * This can happen both because read ops or failed write ops don't
+ * change serial number, and also due to race since we access the
+ * number unlocked (the race can cause less detectable ordering problems,
+ * in which case we'll deadlock and report: fix manually in that case).
+ */
+static void figure_deps(char *filename[], struct op *op[],
+ struct key_user user[], unsigned num_users,
+ unsigned num_files)
+{
+ /* We assume database starts empty. */
+ const struct TDB_DATA *data = &tdb_null;
+
+ if (!sort_deps(filename, op, user, num_users, data, num_files))
+ fail(filename[user[0].file], user[0].op_num+1,
+ "Could not resolve inter-dependencies");
+
+ check_dep_sorting(user, num_users, num_files);
+}
+
+static void sort_ops(struct keyinfo hash[], char *filename[], struct op *op[],
+ unsigned int num)
+{
+ unsigned int h;
+
+ /* Gcc nexted function extension. How cool is this? */
+ int compare_serial(const void *_a, const void *_b)
+ {
+ const struct key_user *a = _a, *b = _b;
+
+ /* First, maintain order within any trace file. */
+ if (a->file == b->file)
+ return a->op_num - b->op_num;
+
+ /* Otherwise, arrange by serial order. */
+ return op[a->file][a->op_num].serial
+ - op[b->file][b->op_num].serial;
+ }
+
+ /* Now sort into serial order. */
+ for (h = 0; h < total_keys * 2; h++) {
+ struct key_user *user = hash[h].user;
+
+ qsort(user, hash[h].num_users, sizeof(user[0]), compare_serial);
+ figure_deps(filename, op, user, hash[h].num_users, num);
+ }
+}
+
+static int destroy_depend(struct depend *dep)
+{
+ list_del(&dep->pre_list);
+ list_del(&dep->post_list);
+ return 0;
+}
+
static void add_dependency(void *ctx,
struct op *op[],
char *filename[],
unsigned int satisfies_file,
unsigned int satisfies_opnum)
{
- struct depend *post, *pre;
+ struct depend *dep;
unsigned int needs_start, sat_start;
/* We don't depend on ourselves. */
}
}
- post = talloc(ctx, struct depend);
- post->file = needs_file;
- post->op = needs_opnum;
- list_add(&op[satisfies_file][satisfies_opnum].post, &post->list);
-
- pre = talloc(ctx, struct depend);
- pre->file = satisfies_file;
- pre->op = satisfies_opnum;
- list_add(&op[needs_file][needs_opnum].pre, &pre->list);
+ dep = talloc(ctx, struct depend);
+ dep->needs_file = needs_file;
+ dep->needs_opnum = needs_opnum;
+ dep->satisfies_file = satisfies_file;
+ dep->satisfies_opnum = satisfies_opnum;
+ list_add(&op[satisfies_file][satisfies_opnum].post, &dep->post_list);
+ list_add(&op[needs_file][needs_opnum].pre, &dep->pre_list);
+ talloc_set_destructor(dep, destroy_depend);
}
#if TRAVERSALS_TAKE_TRANSACTION_LOCK
}
#endif /* TRAVERSALS_TAKE_TRANSACTION_LOCK */
+static bool changes_db(const struct op *op)
+{
+ return gives(op, NULL) != NULL;
+}
+
+static void depend_on_previous(struct op *op[],
+ char *filename[],
+ unsigned int num,
+ struct key_user user[],
+ unsigned int i,
+ int prev)
+{
+ bool deps[num];
+ int j;
+
+ if (i == 0)
+ return;
+
+ if (prev == i - 1) {
+ /* Just depend on previous. */
+ add_dependency(NULL, op, filename,
+ user[i].file, user[i].op_num,
+ user[prev].file, user[prev].op_num);
+ return;
+ }
+
+ /* We have to wait for the readers. Find last one in *each* file. */
+ memset(deps, 0, sizeof(deps));
+ deps[user[i].file] = true;
+ for (j = i - 1; j > prev; j--) {
+ if (!deps[user[j].file]) {
+ add_dependency(NULL, op, filename,
+ user[i].file, user[i].op_num,
+ user[j].file, user[j].op_num);
+ deps[user[j].file] = true;
+ }
+ }
+}
+
+/* This is simple, but not complete. We don't take into account
+ * indirect dependencies. */
+static void optimize_dependencies(struct op *op[], unsigned int num_ops[],
+ unsigned int num)
+{
+ unsigned int i, j;
+
+ for (i = 0; i < num; i++) {
+ int deps[num];
+
+ for (j = 0; j < num; j++)
+ deps[j] = -1;
+
+ for (j = 1; j < num_ops[i]; j++) {
+ struct depend *dep, *next;
+
+ list_for_each_safe(&op[i][j].pre, dep, next, pre_list) {
+ if (deps[dep->satisfies_file]
+ >= (int)dep->satisfies_opnum)
+ talloc_free(dep);
+ else
+ deps[dep->satisfies_file]
+ = dep->satisfies_opnum;
+ }
+ }
+ }
+}
+
static void derive_dependencies(char *filename[],
struct op *op[], unsigned int num_ops[],
unsigned int num)
{
struct keyinfo *hash;
- unsigned int i, j;
+ unsigned int h, i;
/* Create hash table for faster key lookup. */
hash = hash_ops(op, num_ops, num);
- /* We make the naive assumption that two ops on the same key
- * have to be ordered; it's overkill. */
- for (i = 0; i < total_keys * 2; i++) {
- for (j = 1; j < hash[i].num_users; j++) {
- add_dependency(hash, op, filename,
- hash[i].user[j].file,
- hash[i].user[j].op_num,
- hash[i].user[j-1].file,
- hash[i].user[j-1].op_num);
+ /* Sort them by serial number. */
+ sort_ops(hash, filename, op, num);
+
+ /* Create dependencies back to the last change, rather than
+ * creating false dependencies by naively making each one
+ * depend on the previous. This has two purposes: it makes
+ * later optimization simpler, and it also avoids deadlock with
+ * same sequence number ops inside traversals (if one
+ * traversal doesn't write anything, two ops can have the same
+ * sequence number yet we can create a traversal dependency
+ * the other way). */
+ for (h = 0; h < total_keys * 2; h++) {
+ int prev = -1;
+
+ if (hash[h].num_users < 2)
+ continue;
+
+ for (i = 0; i < hash[h].num_users; i++) {
+ if (changes_db(&op[hash[h].user[i].file]
+ [hash[h].user[i].op_num])) {
+ depend_on_previous(op, filename, num,
+ hash[h].user, i, prev);
+ prev = i;
+ } else if (prev >= 0)
+ add_dependency(hash, op, filename,
+ hash[h].user[i].file,
+ hash[h].user[i].op_num,
+ hash[h].user[prev].file,
+ hash[h].user[prev].op_num);
}
}
#if TRAVERSALS_TAKE_TRANSACTION_LOCK
make_traverse_depends(filename, op, num_ops, num);
#endif
+
+ optimize_dependencies(op, num_ops, num);
}
int main(int argc, char *argv[])
projects / ccan / blobdiff