Author: Remi Meier <remi.me...@gmail.com> Branch: c8-reshare-pages Changeset: r2154:9e9180b5bdf3 Date: 2018-03-18 16:01 +0100 http://bitbucket.org/pypy/stmgc/changeset/9e9180b5bdf3/
Log: add some comments diff --git a/c8/TODO b/c8/TODO --- a/c8/TODO +++ b/c8/TODO @@ -1,3 +1,10 @@ +- MOVNTI for non-temporal 32bit store (for read markers) +- do we actually know if paying the cost of getting the current read-version + in every stm_read is lower than paying the cost of zeroing the readmarker + on every commit (and just use a flag)? + +- stm_enable_atomic() simply sets a huge value for nursery_mark, which is + unreliable in theory - investigate if userfaultfd() helps: http://kernelnewbies.org/Linux_4.3#head-3deefea7b0add8c1b171b0e72ce3b69c5ed35cb0 diff --git a/c8/doc/page-resharing.md b/c8/doc/page-resharing.md --- a/c8/doc/page-resharing.md +++ b/c8/doc/page-resharing.md @@ -51,14 +51,14 @@ In signal handler: - if read or write: + if is_read or is_write: if is `RO`: `RO -> ACC` (and `RO -> NOACC` for all others) else if is `NOACC`: if !is_write and noone has `ACC`: `NOACC -> RO` else: - `NOACC -> ACC` + `NOACC -> ACC` (and `RO -> NOACC` for all others) On validate: always imports into `ACC`, into `RO` would be a bug. @@ -66,6 +66,10 @@ 1. Validation of seg0: gets all changes; any `RO` views still around means that there was *no change* in those pages, so the views stay valid. + + XXX: what about the modifications that major GC makes during tracing? how + does it affect the page-sharing in the kernel? + 2. All other segments validate their `ACC` pages; again `RO` pages *cannot* have changes that need importing. 3. While tracing modified objs and overflow objs, remember pages with diff --git a/c8/stm/core.c b/c8/stm/core.c --- a/c8/stm/core.c +++ b/c8/stm/core.c @@ -235,6 +235,7 @@ cl = first_cl; while ((cl = cl->next) != NULL) { if (!needs_abort) { + /* check if there is a conflict: */ struct stm_undo_s *undo = cl->written; struct stm_undo_s *end = cl->written + cl->written_count; for (; undo < end; undo++) { @@ -301,6 +302,7 @@ } if (cl->written_count) { + /* copy most recent version of modified objs to our segment: */ struct stm_undo_s *undo = cl->written; struct stm_undo_s *end = cl->written + cl->written_count; @@ -314,6 +316,13 @@ copy_bk_objs_in_page_from (cl->segment_num, -1, /* any page */ !needs_abort); /* if we abort, we still want to copy everything */ + + /* reason we must always update to the last (non-INEV) + * commit log entry: a currently running transaction in + * segment_num may have backup copies that revert the + * objects in cl->written to a more current revision than + * the cl-entry represents. This is fine as long as we + * *also* validate to that more current revision. */ } dprintf(("_stm_validate() to cl=%p, rev=%lu\n", cl, cl->rev_num)); _______________________________________________ pypy-commit mailing list pypy-commit@python.org https://mail.python.org/mailman/listinfo/pypy-commit
