leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

mmc: block: Add CQE support

Browse Source 
Add CQE support to the block driver, including:
    - optionally using DCMD for flush requests
    - "manually" issuing discard requests
    - issuing read / write requests to the CQE
    - supporting block-layer timeouts
    - handling recovery
    - supporting re-tuning

CQE offers 25% - 50% better random multi-threaded I/O.  There is a slight
(e.g. 2%) drop in sequential read speed but no observable change to sequential
write.

CQE automatically sends the commands to complete requests.  However it only
supports reads / writes and so-called "direct commands" (DCMD).  Furthermore
DCMD is limited to one command at a time, but discards require 3 commands.
That makes issuing discards through CQE very awkward, but some CQE's don't
support DCMD anyway.  So for discards, the existing non-CQE approach is
taken, where the mmc core code issues the 3 commands one at a time i.e.
mmc_erase(). Where DCMD is used, is for issuing flushes.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Adrian Hunter
2017-11-29 15:41:04 +02:00
committed by Ulf Hansson
parent 81196976ed
commit 1e8e55b670
4 changed files with 326 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
drivers/mmc/core/queue.h
View File

@@ -17,6 +17,7 @@ enum mmc_issued {
enum mmc_issue_type {
MMC_ISSUE_SYNC,
MMC_ISSUE_DCMD,
MMC_ISSUE_ASYNC,
MMC_ISSUE_MAX,
};
@@ -92,8 +93,15 @@ struct mmc_queue {
int qcnt;
int in_flight[MMC_ISSUE_MAX];
unsigned int cqe_busy;
#define MMC_CQE_DCMD_BUSY BIT(0)
#define MMC_CQE_QUEUE_FULL BIT(1)
bool use_cqe;
bool recovery_needed;
bool in_recovery;
bool rw_wait;
bool waiting;
struct work_struct recovery_work;
wait_queue_head_t wait;
struct request *complete_req;
struct mutex complete_lock;
@@ -108,11 +116,21 @@ extern void mmc_queue_resume(struct mmc_queue *);
extern unsigned int mmc_queue_map_sg(struct mmc_queue *,
struct mmc_queue_req *);
void mmc_cqe_check_busy(struct mmc_queue *mq);
void mmc_cqe_recovery_notifier(struct mmc_request *mrq);
enum mmc_issue_type mmc_issue_type(struct mmc_queue *mq, struct request *req);
static inline int mmc_tot_in_flight(struct mmc_queue *mq)
{
return mq->in_flight[MMC_ISSUE_SYNC] +
mq->in_flight[MMC_ISSUE_DCMD] +
mq->in_flight[MMC_ISSUE_ASYNC];
}
static inline int mmc_cqe_qcnt(struct mmc_queue *mq)
{
return mq->in_flight[MMC_ISSUE_DCMD] +
mq->in_flight[MMC_ISSUE_ASYNC];
}