Messages in this thread Patch in this message | | | Date | Tue, 09 Sep 2003 17:04:10 +1000 | From | Nick Piggin <> | Subject | Re: Badness in as_completed_request warning |
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Dave Olien wrote:
>On Tue, Sep 09, 2003 at 01:40:57PM +1000, Nick Piggin wrote: > >>Hi Dave, >>Can you try 2.6.0-test5 with the following patch please. Thanks >> >> > >I applied this patch, and gave it a shot. It seems to have made things >worse. Instead of the warnings occurring only at the end of the mkfs >runs, they now occur pretty much constantly, and it finally ends >with an Bug_On. Attached is the console output. There are 20 >occurrances of Badness in as-iosched.c line 1020. There is one >occurrance of Badness in as-iosched.c line 1025. The Bug_On() is in >as-iosched.c line 1243. > >Console output is attached. >
Thanks Dave, Can you try this one? I can't reproduce the problem here as I don't have enough disks unfortunately. Thanks
Nick linux-2.6-npiggin/drivers/block/as-iosched.c | 60 +++++++++++++++++++-------- 1 files changed, 43 insertions(+), 17 deletions(-)
diff -puN drivers/block/as-iosched.c~as-warn-fix drivers/block/as-iosched.c --- linux-2.6/drivers/block/as-iosched.c~as-warn-fix 2003-09-09 17:02:41.000000000 +1000 +++ linux-2.6-npiggin/drivers/block/as-iosched.c 2003-09-09 17:02:41.000000000 +1000 @@ -373,7 +373,7 @@ static void as_move_to_dispatch(struct a * direct IO, then move the alias to the dispatch list and then add the * request. */ -static void as_add_arq_rb(struct as_data *ad, struct as_rq *arq) +static int as_add_arq_rb(struct as_data *ad, struct as_rq *arq) { struct as_rq *alias; struct request *rq = arq->request; @@ -381,10 +381,20 @@ static void as_add_arq_rb(struct as_data arq->rb_key = rq_rb_key(rq); /* This can be caused by direct IO */ +#if 0 while ((alias = __as_add_arq_rb(ad, arq))) as_move_to_dispatch(ad, alias); +#endif + if ((alias = __as_add_arq_rb(ad, arq))) { + arq->state = AS_RQ_NEW; + list_add_tail(&arq->request->queuelist, + &alias->request->queuelist); + + return 1; + } rb_insert_color(&arq->rb_node, ARQ_RB_ROOT(ad, arq)); + return 0; } static inline void as_del_arq_rb(struct as_data *ad, struct as_rq *arq) @@ -1131,7 +1141,21 @@ static void as_move_to_dispatch(struct a * take it off the sort and fifo list, add to dispatch queue */ as_remove_queued_request(ad->q, arq->request); + + for (;;) { + struct list_head *alias = &arq->request->queuelist; + + if (!list_empty(alias)) { + struct request *rq; + rq = list_entry_rq(alias->next); + list_del(&rq->queuelist); + list_add_tail(&rq->queuelist, ad->dispatch); + } else + break; + } + list_add_tail(&arq->request->queuelist, ad->dispatch); + if (arq->io_context && arq->io_context->aic) atomic_inc(&arq->io_context->aic->nr_dispatched); @@ -1303,22 +1327,22 @@ static void as_add_request(struct as_dat arq->is_sync = 0; data_dir = arq->is_sync; - arq->io_context = as_get_io_context(); + if (!as_add_arq_rb(ad, arq)) { + arq->io_context = as_get_io_context(); - if (arq->io_context) { - atomic_inc(&arq->io_context->aic->nr_queued); - as_update_iohist(arq->io_context->aic, arq->request); - } - - as_add_arq_rb(ad, arq); + if (arq->io_context) { + atomic_inc(&arq->io_context->aic->nr_queued); + as_update_iohist(arq->io_context->aic, arq->request); + } - /* - * set expire time (only used for reads) and add to fifo list - */ - arq->expires = jiffies + ad->fifo_expire[data_dir]; - list_add_tail(&arq->fifo, &ad->fifo_list[data_dir]); - arq->state = AS_RQ_QUEUED; - as_update_arq(ad, arq); /* keep state machine up to date */ + /* + * set expire time (only used for reads) and add to fifo list + */ + arq->expires = jiffies + ad->fifo_expire[data_dir]; + list_add_tail(&arq->fifo, &ad->fifo_list[data_dir]); + arq->state = AS_RQ_QUEUED; + as_update_arq(ad, arq); /* keep state machine up to date */ + } } /* @@ -1495,7 +1519,8 @@ static void as_merged_request(request_qu */ if (rq_rb_key(req) != arq->rb_key) { as_del_arq_rb(ad, arq); - as_add_arq_rb(ad, arq); + if (as_add_arq_rb(ad, arq)) + WARN_ON(1); /* * Note! At this stage of this and the next function, our next * request may not be optimal - eg the request may have "grown" @@ -1526,7 +1551,8 @@ as_merged_requests(request_queue_t *q, s if (rq_rb_key(req) != arq->rb_key) { as_del_arq_rb(ad, arq); - as_add_arq_rb(ad, arq); + if (as_add_arq_rb(ad, arq)) + WARN_ON(1); } /* _
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