diff options
Diffstat (limited to 'src/backend/storage/aio/aio.c')
| -rw-r--r-- | src/backend/storage/aio/aio.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/src/backend/storage/aio/aio.c b/src/backend/storage/aio/aio.c index c64d815ebd1..3643f27ad6e 100644 --- a/src/backend/storage/aio/aio.c +++ b/src/backend/storage/aio/aio.c @@ -556,6 +556,13 @@ bool pgaio_io_was_recycled(PgAioHandle *ioh, uint64 ref_generation, PgAioHandleState *state) { *state = ioh->state; + + /* + * Ensure that we don't see an earlier state of the handle than ioh->state + * due to compiler or CPU reordering. This protects both ->generation as + * directly used here, and other fields in the handle accessed in the + * caller if the handle was not reused. + */ pg_read_barrier(); return ioh->generation != ref_generation; @@ -752,7 +759,7 @@ pgaio_io_wait_for_free(void) { int reclaimed = 0; - pgaio_debug(DEBUG2, "waiting for free IO with %d pending, %d in-flight, %d idle IOs", + pgaio_debug(DEBUG2, "waiting for free IO with %d pending, %u in-flight, %u idle IOs", pgaio_my_backend->num_staged_ios, dclist_count(&pgaio_my_backend->in_flight_ios), dclist_count(&pgaio_my_backend->idle_ios)); @@ -773,7 +780,12 @@ pgaio_io_wait_for_free(void) * Note that no interrupts are processed between the state check * and the call to reclaim - that's important as otherwise an * interrupt could have already reclaimed the handle. + * + * Need to ensure that there's no reordering, in the more common + * paths, where we wait for IO, that's done by + * pgaio_io_was_recycled(). */ + pg_read_barrier(); pgaio_io_reclaim(ioh); reclaimed++; } @@ -797,7 +809,7 @@ pgaio_io_wait_for_free(void) if (dclist_count(&pgaio_my_backend->in_flight_ios) == 0) ereport(ERROR, errmsg_internal("no free IOs despite no in-flight IOs"), - errdetail_internal("%d pending, %d in-flight, %d idle IOs", + errdetail_internal("%d pending, %u in-flight, %u idle IOs", pgaio_my_backend->num_staged_ios, dclist_count(&pgaio_my_backend->in_flight_ios), dclist_count(&pgaio_my_backend->idle_ios))); @@ -828,7 +840,7 @@ pgaio_io_wait_for_free(void) case PGAIO_HS_COMPLETED_IO: case PGAIO_HS_SUBMITTED: pgaio_debug_io(DEBUG2, ioh, - "waiting for free io with %d in flight", + "waiting for free io with %u in flight", dclist_count(&pgaio_my_backend->in_flight_ios)); /* @@ -852,7 +864,12 @@ pgaio_io_wait_for_free(void) * check and the call to reclaim - that's important as * otherwise an interrupt could have already reclaimed the * handle. + * + * Need to ensure that there's no reordering, in the more + * common paths, where we wait for IO, that's done by + * pgaio_io_was_recycled(). */ + pg_read_barrier(); pgaio_io_reclaim(ioh); break; } @@ -1252,7 +1269,7 @@ pgaio_closing_fd(int fd) break; pgaio_debug_io(DEBUG2, ioh, - "waiting for IO before FD %d gets closed, %d in-flight IOs", + "waiting for IO before FD %d gets closed, %u in-flight IOs", fd, dclist_count(&pgaio_my_backend->in_flight_ios)); /* see comment in pgaio_io_wait_for_free() about raciness */ @@ -1288,7 +1305,7 @@ pgaio_shutdown(int code, Datum arg) uint64 generation = ioh->generation; pgaio_debug_io(DEBUG2, ioh, - "waiting for IO to complete during shutdown, %d in-flight IOs", + "waiting for IO to complete during shutdown, %u in-flight IOs", dclist_count(&pgaio_my_backend->in_flight_ios)); /* see comment in pgaio_io_wait_for_free() about raciness */ |