Hi, Doesn't it consider SD path? It have a problem with uninitialized 'context_info'. 'context_info' is moved into mmc_host struct in v4. Please, could you explain the reason in brief?
Thanks, Seungwon Jeon On Wednesday, December 05, 2012, Konstantin Dorfman wrote: > When current request is running on the bus and if next request fetched > by mmcqd is NULL, mmc context (mmcqd thread) gets blocked until the > current request completes. This means if new request comes in while > the mmcqd thread is blocked, this new request can not be prepared in > parallel to current ongoing request. This may result in latency to > start new request. > > This change allows to wake up the MMC thread (which > is waiting for the current running request to complete). Now once the > MMC thread is woken up, new request can be fetched and prepared in > parallel to current running request which means this new request can > be started immediately after the current running request completes. > > With this change read throughput is improved by 16%. > > Signed-off-by: Konstantin Dorfman <[email protected]> > --- > v4: keeps new synchronization mechanism within mmc/core > layer, so mmc/core external API's are not changed. > - context_info moved into mmc_host struct > - context_info initialized in mmc_attach_mmc() > > v3: > - new MMC_QUEUE_NEW_REQUEST flag to mark new request case > - lock added to update is_new_req flag > - condition for sending new req notification changed > - Moved start waiting for new req notification > after fetching NULL > v2: > - Removed synchronization flags > - removed lock from done() > - flags names changed > v1: > - Initial submit > > diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c > index 21056b9..f4f295e 100644 > --- a/drivers/mmc/card/block.c > +++ b/drivers/mmc/card/block.c > @@ -113,17 +113,6 @@ struct mmc_blk_data { > > static DEFINE_MUTEX(open_lock); > > -enum mmc_blk_status { > - MMC_BLK_SUCCESS = 0, > - MMC_BLK_PARTIAL, > - MMC_BLK_CMD_ERR, > - MMC_BLK_RETRY, > - MMC_BLK_ABORT, > - MMC_BLK_DATA_ERR, > - MMC_BLK_ECC_ERR, > - MMC_BLK_NOMEDIUM, > -}; > - > module_param(perdev_minors, int, 0444); > MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device"); > > @@ -1363,9 +1352,12 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, > struct request *rqc) > areq = &mq->mqrq_cur->mmc_active; > } else > areq = NULL; > - areq = mmc_start_req(card->host, areq, (int *) &status); > - if (!areq) > + areq = mmc_start_req(card->host, areq, (int *)&status); > + if (!areq) { > + if (status == MMC_BLK_NEW_REQUEST) > + mq->flags |= MMC_QUEUE_NEW_REQUEST; > return 0; > + } > > mq_rq = container_of(areq, struct mmc_queue_req, mmc_active); > brq = &mq_rq->brq; > @@ -1374,6 +1366,8 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, > struct request *rqc) > mmc_queue_bounce_post(mq_rq); > > switch (status) { > + case MMC_BLK_NEW_REQUEST: > + BUG(); /* should never get here */ > case MMC_BLK_SUCCESS: > case MMC_BLK_PARTIAL: > /* > @@ -1486,6 +1480,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, > struct request *req) > goto out; > } > > + mq->flags &= ~MMC_QUEUE_NEW_REQUEST; > if (req && req->cmd_flags & REQ_DISCARD) { > /* complete ongoing async transfer before issuing discard */ > if (card->host->areq) > @@ -1505,7 +1500,7 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, > struct request *req) > } > > out: > - if (!req) > + if (!req && !(mq->flags & MMC_QUEUE_NEW_REQUEST)) > /* release host only when there are no more requests */ > mmc_release_host(card->host); > return ret; > diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c > index fadf52e..0c37b49 100644 > --- a/drivers/mmc/card/queue.c > +++ b/drivers/mmc/card/queue.c > @@ -22,7 +22,6 @@ > > #define MMC_QUEUE_BOUNCESZ 65536 > > -#define MMC_QUEUE_SUSPENDED (1 << 0) > > /* > * Prepare a MMC request. This just filters out odd stuff. > @@ -63,11 +62,20 @@ static int mmc_queue_thread(void *d) > set_current_state(TASK_INTERRUPTIBLE); > req = blk_fetch_request(q); > mq->mqrq_cur->req = req; > + if (!req && mq->mqrq_prev->req && > + !(mq->mqrq_prev->req->cmd_flags & REQ_FLUSH) && > + !(mq->mqrq_prev->req->cmd_flags & REQ_DISCARD)) > + mq->card->host->context_info.is_waiting_last_req = true; > + > spin_unlock_irq(q->queue_lock); > > if (req || mq->mqrq_prev->req) { > set_current_state(TASK_RUNNING); > mq->issue_fn(mq, req); > + if (mq->flags & MMC_QUEUE_NEW_REQUEST) { > + mq->flags &= ~MMC_QUEUE_NEW_REQUEST; > + continue; /* fetch again */ > + } > > /* > * Current request becomes previous request > @@ -103,6 +111,8 @@ static void mmc_request_fn(struct request_queue *q) > { > struct mmc_queue *mq = q->queuedata; > struct request *req; > + unsigned long flags; > + struct mmc_context_info *cntx; > > if (!mq) { > while ((req = blk_fetch_request(q)) != NULL) { > @@ -112,7 +122,20 @@ static void mmc_request_fn(struct request_queue *q) > return; > } > > - if (!mq->mqrq_cur->req && !mq->mqrq_prev->req) > + cntx = &mq->card->host->context_info; > + if (!mq->mqrq_cur->req && mq->mqrq_prev->req) { > + /* > + * New MMC request arrived when MMC thread may be > + * blocked on the previous request to be complete > + * with no current request fetched > + */ > + spin_lock_irqsave(&cntx->lock, flags); > + if (cntx->is_waiting_last_req) { > + cntx->is_new_req = true; > + wake_up_interruptible(&cntx->wait); > + } > + spin_unlock_irqrestore(&cntx->lock, flags); > + } else if (!mq->mqrq_cur->req && !mq->mqrq_prev->req) > wake_up_process(mq->thread); > } > > diff --git a/drivers/mmc/card/queue.h b/drivers/mmc/card/queue.h > index d2a1eb4..970d9e7 100644 > --- a/drivers/mmc/card/queue.h > +++ b/drivers/mmc/card/queue.h > @@ -26,6 +26,8 @@ struct mmc_queue { > struct mmc_card *card; > struct task_struct *thread; > struct semaphore thread_sem; > +#define MMC_QUEUE_SUSPENDED (1 << 0) > +#define MMC_QUEUE_NEW_REQUEST (1 << 1) > unsigned int flags; > int (*issue_fn)(struct mmc_queue *, struct request > *); > void *data; > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c > index aaed768..855336d 100644 > --- a/drivers/mmc/core/core.c > +++ b/drivers/mmc/core/core.c > @@ -319,11 +319,44 @@ out: > } > EXPORT_SYMBOL(mmc_start_bkops); > > +/* > + * mmc_wait_data_done() - done callback for data request > + * @mrq: done data request > + * > + * Wakes up mmc context, passed as callback to host controller driver > + */ > +static void mmc_wait_data_done(struct mmc_request *mrq) > +{ > + mrq->host->context_info.is_done_rcv = true; > + wake_up_interruptible(&mrq->host->context_info.wait); > +} > + > static void mmc_wait_done(struct mmc_request *mrq) > { > complete(&mrq->completion); > } > > +/* > + *__mmc_start_data_req() - starts data request > + * @host: MMC host to start the request > + * @mrq: data request to start > + * > + * Fills done callback that will be used when request are done by card. > + * Starts data mmc request execution > + */ > +static int __mmc_start_data_req(struct mmc_host *host, struct mmc_request > *mrq) > +{ > + mrq->done = mmc_wait_data_done; > + mrq->host = host; > + if (mmc_card_removed(host->card)) { > + mrq->cmd->error = -ENOMEDIUM; > + return -ENOMEDIUM; > + } > + mmc_start_request(host, mrq); > + > + return 0; > +} > + > static int __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq) > { > init_completion(&mrq->completion); > @@ -337,6 +370,60 @@ static int __mmc_start_req(struct mmc_host *host, struct > mmc_request *mrq) > return 0; > } > > +/* > + * mmc_wait_for_data_req_done() - wait for request completed or new > + * request notification arrives > + * @host: MMC host to prepare the command. > + * @mrq: MMC request to wait for > + * > + * Blocks MMC context till host controller will ack end of data request > + * execution or new request arrives from block layer. Handles > + * command retries. > + * > + * Returns enum mmc_blk_status after checking errors. > + */ > +static int mmc_wait_for_data_req_done(struct mmc_host *host, > + struct mmc_request *mrq) > +{ > + struct mmc_command *cmd; > + struct mmc_context_info *context_info = &host->context_info; > + int err; > + unsigned long flags; > + > + while (1) { > + wait_event_interruptible(context_info->wait, > + (context_info->is_done_rcv || > + context_info->is_new_req)); > + spin_lock_irqsave(&context_info->lock, flags); > + context_info->is_waiting_last_req = false; > + spin_unlock_irqrestore(&context_info->lock, flags); > + if (context_info->is_done_rcv) { > + context_info->is_done_rcv = false; > + context_info->is_new_req = false; > + cmd = mrq->cmd; > + if (!cmd->error || !cmd->retries || > + mmc_card_removed(host->card)) { > + err = host->areq->err_check(host->card, > + host->areq); > + break; /* return err */ > + } else { > + pr_info("%s: req failed (CMD%u): %d, > retrying...\n", > + mmc_hostname(host), > + cmd->opcode, cmd->error); > + cmd->retries--; > + cmd->error = 0; > + host->ops->request(host, mrq); > + continue; /* wait for done/new event again */ > + } > + } else if (context_info->is_new_req) { > + context_info->is_new_req = false; > + err = MMC_BLK_NEW_REQUEST; > + break; /* return err */ > + } > + } /* while */ > + return err; > +} > + > static void mmc_wait_for_req_done(struct mmc_host *host, > struct mmc_request *mrq) > { > @@ -426,8 +513,21 @@ struct mmc_async_req *mmc_start_req(struct mmc_host > *host, > mmc_pre_req(host, areq->mrq, !host->areq); > > if (host->areq) { > - mmc_wait_for_req_done(host, host->areq->mrq); > - err = host->areq->err_check(host->card, host->areq); > + err = mmc_wait_for_data_req_done(host, host->areq->mrq); > + if (err == MMC_BLK_NEW_REQUEST) { > + if (areq) { > + pr_err("%s: new request while areq = %p", > + mmc_hostname(host), areq); > + BUG_ON(1); > + } > + if (error) > + *error = err; > + /* > + * The previous request was not completed, > + * nothing to return > + */ > + return NULL; > + } > /* > * Check BKOPS urgency for each R1 response > */ > @@ -439,7 +539,7 @@ struct mmc_async_req *mmc_start_req(struct mmc_host *host, > } > > if (!err && areq) > - start_err = __mmc_start_req(host, areq->mrq); > + start_err = __mmc_start_data_req(host, areq->mrq); > > if (host->areq) > mmc_post_req(host, host->areq->mrq, 0); > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c > index e6e3911..dd3bc11 100644 > --- a/drivers/mmc/core/mmc.c > +++ b/drivers/mmc/core/mmc.c > @@ -1497,6 +1497,12 @@ int mmc_attach_mmc(struct mmc_host *host) > BUG_ON(!host); > WARN_ON(!host->claimed); > > + spin_lock_init(&host->context_info.lock); > + host->context_info.is_new_req = false; > + host->context_info.is_done_rcv = false; > + host->context_info.is_waiting_last_req = false; > + init_waitqueue_head(&host->context_info.wait); > + > /* Set correct bus mode for MMC before attempting attach */ > if (!mmc_host_is_spi(host)) > mmc_set_bus_mode(host, MMC_BUSMODE_OPENDRAIN); > diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h > index 5c69315..be2500a 100644 > --- a/include/linux/mmc/card.h > +++ b/include/linux/mmc/card.h > @@ -187,6 +187,18 @@ struct sdio_func_tuple; > > #define SDIO_MAX_FUNCS 7 > > +enum mmc_blk_status { > + MMC_BLK_SUCCESS = 0, > + MMC_BLK_PARTIAL, > + MMC_BLK_CMD_ERR, > + MMC_BLK_RETRY, > + MMC_BLK_ABORT, > + MMC_BLK_DATA_ERR, > + MMC_BLK_ECC_ERR, > + MMC_BLK_NOMEDIUM, > + MMC_BLK_NEW_REQUEST, > +}; > + > /* The number of MMC physical partitions. These consist of: > * boot partitions (2), general purpose partitions (4) in MMC v4.4. > */ > diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h > index 5bf7c22..724cc95 100644 > --- a/include/linux/mmc/core.h > +++ b/include/linux/mmc/core.h > @@ -120,6 +120,7 @@ struct mmc_data { > s32 host_cookie; /* host private data */ > }; > > +struct mmc_host; > struct mmc_request { > struct mmc_command *sbc; /* SET_BLOCK_COUNT for > multiblock */ > struct mmc_command *cmd; > @@ -128,9 +129,9 @@ struct mmc_request { > > struct completion completion; > void (*done)(struct mmc_request *);/* completion > function */ > + struct mmc_host *host; > }; > > -struct mmc_host; > struct mmc_card; > struct mmc_async_req; > > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h > index 23df21e..08a8203 100644 > --- a/include/linux/mmc/host.h > +++ b/include/linux/mmc/host.h > @@ -176,6 +176,21 @@ struct mmc_supply { > struct regulator *vqmmc; /* Optional Vccq supply */ > }; > > +/** > + * mmc_context_info - synchronization details for mmc context > + * @is_done_rcv wake up reason was done request > + * @is_new_req wake up reason was new request > + * @is_waiting_last_req mmc context waiting for single running request > + * @wait wait queue > + */ > +struct mmc_context_info { > + bool is_done_rcv; > + bool is_new_req; > + bool is_waiting_last_req; > + wait_queue_head_t wait; > + spinlock_t lock; > +}; > + > struct mmc_host { > struct device *parent; > struct device class_dev; > @@ -330,6 +345,7 @@ struct mmc_host { > struct dentry *debugfs_root; > > struct mmc_async_req *areq; /* active async req */ > + struct mmc_context_info context_info; /* async synchronization info */ > > #ifdef CONFIG_FAIL_MMC_REQUEST > struct fault_attr fail_mmc_request; > -- > 1.7.6 > -- > Konstantin Dorfman, > QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, > Inc. is a member of Code Aurora Forum, > hosted by The Linux Foundation > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
