I checked this commit.
v3 doesn't work in dw_mmc host driver.
It makes some driver warning while v1 is fine.
I'm finding the reason. And could you check minor one below?
On Tuesday, November 13, 2012, Seungwon Jeon <tgih....@samsung.com>
> Hi Konstantin,
>
> I'm looking into this patch.
> Idea looks good as a whole.
>
> On Tuesday, November 13, 2012, Konstantin Dorfman <kdorf...@codeaurora.org>
> 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 <kdorf...@codeaurora.org>
> > ---
> > 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 172a768..34d8bd9 100644
> > --- a/drivers/mmc/card/block.c
> > +++ b/drivers/mmc/card/block.c
> > @@ -112,17 +112,6 @@ 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");
> >
> > @@ -1225,6 +1214,7 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req
> > *mqrq,
> >
> > mqrq->mmc_active.mrq = &brq->mrq;
> > mqrq->mmc_active.err_check = mmc_blk_err_check;
> > + mqrq->mmc_active.mrq->context_info = &mq->context_info;
> >
> > mmc_queue_bounce_pre(mqrq);
> > }
> > @@ -1284,9 +1274,12 @@ 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;
> > @@ -1295,6 +1288,8 @@ 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:
> > /*
> > @@ -1367,7 +1362,8 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq,
> > struct request *rqc)
> > * prepare it again and resend.
> > */
> > mmc_blk_rw_rq_prep(mq_rq, card, disable_multi, mq);
> > - mmc_start_req(card->host, &mq_rq->mmc_active, NULL);
> > + mmc_start_req(card->host, &mq_rq->mmc_active,
> > + (int *)&status);
> Here, we'll try to send previous request which is not completed successfully.
> And then at the top of do~while, mmc_start_req will be called for current
> request and get the status.
> Above change looks like unnecessary. Is there any reason?
>
> Thanks,
> Seungwon Jeon
>
> > }
> > } while (ret);
> >
> > @@ -1407,6 +1403,8 @@ 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)
> > @@ -1426,9 +1424,10 @@ 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..ef575ac 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->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 +111,7 @@ static void mmc_request_fn(struct request_queue *q)
> > {
> > struct mmc_queue *mq = q->queuedata;
> > struct request *req;
> > + unsigned long flags;
> >
> > if (!mq) {
> > while ((req = blk_fetch_request(q)) != NULL) {
> > @@ -111,8 +120,19 @@ static void mmc_request_fn(struct request_queue *q)
> > }
> > return;
> > }
> > -
> > - if (!mq->mqrq_cur->req && !mq->mqrq_prev->req)
> > + 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(&mq->context_info.lock, flags);
> > + if (mq->context_info.is_waiting_last_req) {
> > + mq->context_info.is_new_req = true;
> > + wake_up_interruptible(&mq->context_info.wait);
> > + }
> > + spin_unlock_irqrestore(&mq->context_info.lock, flags);
> > + } else if (!mq->mqrq_cur->req && !mq->mqrq_prev->req)
> > wake_up_process(mq->thread);
> > }
> >
> > @@ -262,6 +282,11 @@ int mmc_init_queue(struct mmc_queue *mq, struct
> > mmc_card *card,
> > }
> >
> > sema_init(&mq->thread_sem, 1);
> > + spin_lock_init(&mq->context_info.lock);
> > + mq->context_info.is_new_req = false;
> > + mq->context_info.is_done_rcv = false;
> > + mq->context_info.is_waiting_last_req = false;
> > + init_waitqueue_head(&mq->context_info.wait);
> >
> > mq->thread = kthread_run(mmc_queue_thread, mq, "mmcqd/%d%s",
> > host->index, subname ? subname : "");
> > diff --git a/drivers/mmc/card/queue.h b/drivers/mmc/card/queue.h
> > index d2a1eb4..f5885e9 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;
> > @@ -33,6 +35,7 @@ struct mmc_queue {
> > struct mmc_queue_req mqrq[2];
> > struct mmc_queue_req *mqrq_cur;
> > struct mmc_queue_req *mqrq_prev;
> > + struct mmc_context_info context_info;
> > };
> >
> > extern int mmc_init_queue(struct mmc_queue *, struct mmc_card *,
> > spinlock_t *,
> > diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> > index 06c42cf..3374195 100644
> > --- a/drivers/mmc/core/core.c
> > +++ b/drivers/mmc/core/core.c
> > @@ -316,11 +316,43 @@ 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->context_info->is_done_rcv = true;
> > + wake_up_interruptible(&mrq->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;
> > + 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);
> > @@ -334,6 +366,60 @@ 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 = mrq->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)
> > {
> > @@ -396,23 +482,17 @@ static void mmc_post_req(struct mmc_host *host,
> > struct mmc_request *mrq,
> > }
> >
> > /**
> > - * mmc_start_req - start a non-blocking request
> > - * @host: MMC host to start command
> > - * @areq: async request to start
> > - * @error: out parameter returns 0 for success, otherwise non zero
> > - *
> > - * Start a new MMC custom command request for a host.
> > - * If there is on ongoing async request wait for completion
> > - * of that request and start the new one and return.
> > - * Does not wait for the new request to complete.
> > + * mmc_start_req - start a non-blocking data request
> > + * @host: MMC host to start the command
> > + * @areq: async request to start
> > + * @error: out parameter; returns 0 for success, otherwise non zero
> > *
> > - * Returns the completed request, NULL in case of none completed.
> > - * Wait for the an ongoing request (previoulsy started) to complete and
> > - * return the completed request. If there is no ongoing request, NULL
> > - * is returned without waiting. NULL is not an error condition.
> > + * Wait for the ongoing request (previoulsy started) to complete and
> > + * return the completed request. If there is no ongoing request, NULL
> > + * is returned without waiting. NULL is not an error condition.
> > */
> > struct mmc_async_req *mmc_start_req(struct mmc_host *host,
> > - struct mmc_async_req *areq, int *error)
> > + struct mmc_async_req *areq, int *error)
> > {
> > int err = 0;
> > int start_err = 0;
> > @@ -423,8 +503,20 @@ 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();
> > + }
> > + *error = err;
Need to check NULL of error.
if (error)
Thanks,
Seungwon Jeon
> > + /*
> > + * The previous request was not completed,
> > + * nothing to return
> > + */
> > + return NULL;
> > + }
> > /*
> > * Check BKOPS urgency for each R1 response
> > */
> > @@ -436,7 +528,7 @@ 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);
> > @@ -452,6 +544,7 @@ struct mmc_async_req *mmc_start_req(struct mmc_host
> > *host,
> >
> > if (error)
> > *error = err;
> > +
> > return data;
> > }
> > EXPORT_SYMBOL(mmc_start_req);
> > diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> > index 943550d..9681d8f 100644
> > --- a/include/linux/mmc/card.h
> > +++ b/include/linux/mmc/card.h
> > @@ -186,6 +186,18 @@ 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 9b9cdaf..aa17096 100644
> > --- a/include/linux/mmc/core.h
> > +++ b/include/linux/mmc/core.h
> > @@ -120,6 +120,21 @@ struct mmc_data {
> > s32 host_cookie; /* host private data */
> > };
> >
> > +/**
> > + * 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_request {
> > struct mmc_command *sbc; /* SET_BLOCK_COUNT for
> > multiblock */
> > struct mmc_command *cmd;
> > @@ -128,6 +143,7 @@ struct mmc_request {
> >
> > struct completion completion;
> > void (*done)(struct mmc_request *);/* completion
> > function */
> > + struct mmc_context_info *context_info;
> > };
> >
> > struct mmc_host;
> > --
> > 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 majord...@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>
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