[pypy-commit] stmgc c8-small-uniform: fix another (currently untestable) bug
Raemi
noreply at buildbot.pypy.org
Wed Dec 3 08:31:15 CET 2014
Author: Remi Meier <remi.meier at gmail.com>
Branch: c8-small-uniform
Changeset: r1513:222d1845dff3
Date: 2014-12-02 17:00 +0100
http://bitbucket.org/pypy/stmgc/changeset/222d1845dff3/
Log: fix another (currently untestable) bug
diff --git a/c8/stm/core.c b/c8/stm/core.c
--- a/c8/stm/core.c
+++ b/c8/stm/core.c
@@ -278,94 +278,108 @@
return;
}
- /* Find the set of segments we need to copy from and lock them: */
- uint64_t segments_to_lock = 1UL << my_segnum;
- cl = first_cl;
- while ((next_cl = cl->next) != NULL) {
- if (next_cl == INEV_RUNNING) {
+ bool needs_abort = false;
+
+ while(1) {
+ /* retry IF: */
+ /* if at the time of "HERE" (s.b.) there happen to be
+ more commits (and bk copies) then it could be that
+ copy_bk_objs_in_page_from (s.b.) reads a bk copy that
+ is itself more recent than last_cl. This is fixed
+ by re-validating. */
+ first_cl = STM_PSEGMENT->last_commit_log_entry;
+ if (first_cl->next == NULL)
+ break;
+
+ /* Find the set of segments we need to copy from and lock them: */
+ uint64_t segments_to_lock = 1UL << my_segnum;
+ cl = first_cl;
+ while ((next_cl = cl->next) != NULL) {
+ if (next_cl == INEV_RUNNING) {
#if STM_TESTS
- if (free_if_abort != (void *)-1)
- free(free_if_abort);
- stm_abort_transaction();
+ if (free_if_abort != (void *)-1)
+ free(free_if_abort);
+ stm_abort_transaction();
#endif
- /* only validate entries up to INEV */
- break;
+ /* only validate entries up to INEV */
+ break;
+ }
+ assert(next_cl->rev_num > cl->rev_num);
+ cl = next_cl;
+
+ if (cl->written_count) {
+ segments_to_lock |= (1UL << cl->segment_num);
+ }
}
- assert(next_cl->rev_num > cl->rev_num);
- cl = next_cl;
+ last_cl = cl;
+ /* HERE */
+ acquire_modification_lock_set(segments_to_lock);
- if (cl->written_count) {
- segments_to_lock |= (1UL << cl->segment_num);
- }
- }
- last_cl = cl;
- acquire_modification_lock_set(segments_to_lock);
+ /* import objects from first_cl to last_cl: */
+ if (first_cl != last_cl) {
+ uint64_t segment_really_copied_from = 0UL;
- /* import objects from first_cl to last_cl: */
- bool needs_abort = false;
- if (first_cl != last_cl) {
- uint64_t segment_really_copied_from = 0UL;
-
- cl = first_cl;
- while ((cl = cl->next) != NULL) {
- if (!needs_abort) {
- struct stm_undo_s *undo = cl->written;
- struct stm_undo_s *end = cl->written + cl->written_count;
- for (; undo < end; undo++) {
- if (_stm_was_read(undo->object)) {
- /* first reset all modified objects from the backup
- copies as soon as the first conflict is detected;
- then we will proceed below to update our segment from
- the old (but unmodified) version to the newer version.
- */
- reset_modified_from_backup_copies(my_segnum);
- needs_abort = true;
- break;
+ cl = first_cl;
+ while ((cl = cl->next) != NULL) {
+ if (!needs_abort) {
+ struct stm_undo_s *undo = cl->written;
+ struct stm_undo_s *end = cl->written + cl->written_count;
+ for (; undo < end; undo++) {
+ if (_stm_was_read(undo->object)) {
+ /* first reset all modified objects from the backup
+ copies as soon as the first conflict is detected;
+ then we will proceed below to update our segment from
+ the old (but unmodified) version to the newer version.
+ */
+ reset_modified_from_backup_copies(my_segnum);
+ needs_abort = true;
+ break;
+ }
}
}
+
+ if (cl->written_count) {
+ struct stm_undo_s *undo = cl->written;
+ struct stm_undo_s *end = cl->written + cl->written_count;
+
+ segment_really_copied_from |= (1UL << cl->segment_num);
+ import_objects(cl->segment_num, -1, undo, end);
+
+ /* here we can actually have our own modified version, so
+ make sure to only copy things that are not modified in our
+ segment... (if we do not abort) */
+ copy_bk_objs_in_page_from
+ (cl->segment_num, -1, /* any page */
+ !needs_abort); /* if we abort, we still want to copy everything */
+ }
+
+ /* last fully validated entry */
+ STM_PSEGMENT->last_commit_log_entry = cl;
+ if (cl == last_cl)
+ break;
}
+ assert(cl == last_cl);
- if (cl->written_count) {
- struct stm_undo_s *undo = cl->written;
- struct stm_undo_s *end = cl->written + cl->written_count;
+ /* XXX: this optimization fails in test_basic.py, bug3 */
+ /* OPT_ASSERT(segment_really_copied_from < (1 << NB_SEGMENTS)); */
+ /* int segnum; */
+ /* for (segnum = 0; segnum < NB_SEGMENTS; segnum++) { */
+ /* if (segment_really_copied_from & (1UL << segnum)) { */
+ /* /\* here we can actually have our own modified version, so */
+ /* make sure to only copy things that are not modified in our */
+ /* segment... (if we do not abort) *\/ */
+ /* copy_bk_objs_in_page_from( */
+ /* segnum, -1, /\* any page *\/ */
+ /* !needs_abort); /\* if we abort, we still want to copy everything *\/ */
+ /* } */
+ /* } */
+ }
- segment_really_copied_from |= (1UL << cl->segment_num);
- import_objects(cl->segment_num, -1, undo, end);
-
- /* here we can actually have our own modified version, so
- make sure to only copy things that are not modified in our
- segment... (if we do not abort) */
- copy_bk_objs_in_page_from
- (cl->segment_num, -1, /* any page */
- !needs_abort); /* if we abort, we still want to copy everything */
- }
-
- /* last fully validated entry */
- STM_PSEGMENT->last_commit_log_entry = cl;
- if (cl == last_cl)
- break;
- }
- assert(cl == last_cl);
-
- /* XXX: this optimization fails in test_basic.py, bug3 */
- /* OPT_ASSERT(segment_really_copied_from < (1 << NB_SEGMENTS)); */
- /* int segnum; */
- /* for (segnum = 0; segnum < NB_SEGMENTS; segnum++) { */
- /* if (segment_really_copied_from & (1UL << segnum)) { */
- /* /\* here we can actually have our own modified version, so */
- /* make sure to only copy things that are not modified in our */
- /* segment... (if we do not abort) *\/ */
- /* copy_bk_objs_in_page_from( */
- /* segnum, -1, /\* any page *\/ */
- /* !needs_abort); /\* if we abort, we still want to copy everything *\/ */
- /* } */
- /* } */
+ /* done with modifications */
+ release_modification_lock_set(segments_to_lock);
}
- /* done with modifications */
- release_modification_lock_set(segments_to_lock);
-
if (needs_abort) {
if (free_if_abort != (void *)-1)
free(free_if_abort);
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