Author: Remi Meier <remi.me...@inf.ethz.ch>
Branch: c8-new-page-handling
Changeset: r1426:fadb937a707d
Date: 2014-09-26 09:57 +0200
http://bitbucket.org/pypy/stmgc/changeset/fadb937a707d/
Log: introduce revision numbers
diff --git a/c8/stm/core.c b/c8/stm/core.c
--- a/c8/stm/core.c
+++ b/c8/stm/core.c
@@ -61,6 +61,7 @@
struct stm_commit_log_entry_s *from,
struct stm_commit_log_entry_s *to)
{
+ assert(from->rev_num >= to->rev_num);
/* walk BACKWARDS the commit log and update the page 'pagenum',
initially at revision 'from', until we reach the revision 'to'. */
@@ -81,6 +82,7 @@
struct stm_commit_log_entry_s *from,
struct stm_commit_log_entry_s *to)
{
+ assert(from->rev_num <= to->rev_num);
if (from == to)
return;
@@ -167,35 +169,18 @@
/* we need to go from 'src_version' to 'target_version'. This
might need a walk into the past or the future. */
- struct stm_commit_log_entry_s *src_version, *target_version, *c1, *c2;
+ struct stm_commit_log_entry_s *src_version, *target_version;
src_version = get_priv_segment(shared_page_holder)->last_commit_log_entry;
target_version = STM_PSEGMENT->last_commit_log_entry;
release_modified_objs_lock(shared_page_holder);
release_all_privatization_locks();
- c1 = src_version;
- c2 = target_version;
- while (1) {
- if (c1 == target_version) {
- go_to_the_future(pagenum, src_version, target_version);
- break;
- }
- if (c2 == src_version) {
- go_to_the_past(pagenum, src_version, target_version);
- break;
- }
- c1 = c1->next;
- if (c1 == (void *)-1 || c1 == NULL) {
- go_to_the_past(pagenum, src_version, target_version);
- break;
- }
- c2 = c2->next;
- if (c2 == (void *)-1 || c2 == NULL) {
- go_to_the_future(pagenum, src_version, target_version);
- break;
- }
- }
+ /* adapt revision of page to our revision: */
+ if (src_version->rev_num < target_version->rev_num)
+ go_to_the_future(pagenum, src_version, target_version);
+ else if (src_version->rev_num > target_version->rev_num)
+ go_to_the_past(pagenum, src_version, target_version);
}
static void _signal_handler(int sig, siginfo_t *siginfo, void *context)
@@ -245,7 +230,7 @@
fprintf(stderr, " INEVITABLE\n");
return;
}
- fprintf(stderr, " entry at %p: seg %d\n", cl, cl->segment_num);
+ fprintf(stderr, " entry at %p: seg %d, rev %lu\n", cl,
cl->segment_num, cl->rev_num);
struct stm_undo_s *undo = cl->written;
struct stm_undo_s *end = undo + cl->written_count;
for (; undo < end; undo++) {
@@ -276,6 +261,9 @@
ordering things, but later. */
acquire_modified_objs_lock(STM_SEGMENT->segment_num);
+ /* XXXXXXXXXX: we shouldn't be able to update pages while someone else
copies
+ from our pages (signal handler / import objs) */
+
bool needs_abort = false;
uint64_t segment_copied_from = 0;
while ((next_cl = cl->next) != NULL) {
@@ -290,10 +278,11 @@
or: XXX do we always need to wait? we should just
break out of this loop and let the caller handle it
if it wants to */
+
_stm_collectable_safe_point();
- acquire_all_privatization_locks();
continue;
}
+ assert(next_cl->rev_num > cl->rev_num);
cl = next_cl;
/*int srcsegnum = cl->segment_num;
@@ -362,6 +351,7 @@
result->next = NULL;
result->segment_num = STM_SEGMENT->segment_num;
+ result->rev_num = -1; /* invalid */
result->written_count = count;
memcpy(result->written, list->items, count * sizeof(struct stm_undo_s));
return result;
@@ -376,9 +366,13 @@
/* try to attach to commit log: */
old = STM_PSEGMENT->last_commit_log_entry;
- if (old->next == NULL &&
- __sync_bool_compare_and_swap(&old->next, NULL, new))
- break; /* success! */
+ if (old->next == NULL) {
+ if ((uintptr_t)new != -1) /* INEVITABLE */
+ new->rev_num = old->rev_num + 1;
+
+ if (__sync_bool_compare_and_swap(&old->next, NULL, new))
+ break; /* success! */
+ }
}
}
@@ -394,6 +388,7 @@
new = _create_commit_log_entry();
if (STM_PSEGMENT->transaction_state == TS_INEVITABLE) {
old = STM_PSEGMENT->last_commit_log_entry;
+ new->rev_num = old->rev_num + 1;
OPT_ASSERT(old->next == (void *)-1);
bool yes = __sync_bool_compare_and_swap(&old->next, (void*)-1, new);
diff --git a/c8/stm/core.h b/c8/stm/core.h
--- a/c8/stm/core.h
+++ b/c8/stm/core.h
@@ -120,10 +120,11 @@
struct stm_commit_log_entry_s {
struct stm_commit_log_entry_s *volatile next;
int segment_num;
+ uint64_t rev_num;
size_t written_count;
struct stm_undo_s written[];
};
-static struct stm_commit_log_entry_s commit_log_root = {NULL, -1, 0};
+static struct stm_commit_log_entry_s commit_log_root = {NULL, -1, 0, 0};
static char *stm_object_pages;
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