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Code Issues Releases Activity

Use atomic load and stores to ensure that the compiler doesn't

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optimize away these loops. Change boolean to int to match what atomic
API supplies. Remove wmb() since the atomic_store_rel() on status.done
ensure the prior writes to status. It also fixes the fact that there
wasn't a rmb() before reading done. This should also be more efficient
since wmb() is fairly heavy weight.

Sponsored by: Netflix
Reviewed by: kib@, jim harris
Differential Revision: https://reviews.freebsd.org/D14053
This commit is contained in:
Warner Losh 2018-01-29 00:00:52 +00:00
parent 8cc3cfa86d
commit 29077eb456
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=328521
3 changed files with 12 additions and 13 deletions
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3
sys/dev/nvme/nvme.c
View File

@ -469,6 +469,5 @@ nvme_completion_poll_cb(void *arg, const struct nvme_completion *cpl)
* the request passed or failed.
*/
memcpy(&status->cpl, cpl, sizeof(*cpl));
wmb();
status->done = TRUE;
atomic_store_rel_int(&status->done, 1);
}

20
sys/dev/nvme/nvme_ctrlr.c
View File

@ -404,10 +404,10 @@ nvme_ctrlr_identify(struct nvme_controller *ctrlr)
{
struct nvme_completion_poll_status status;
status.done = FALSE;
status.done = 0;
nvme_ctrlr_cmd_identify_controller(ctrlr, &ctrlr->cdata,
nvme_completion_poll_cb, &status);
while (status.done == FALSE)
while (!atomic_load_acq_int(&status.done))
pause("nvme", 1);
if (nvme_completion_is_error(&status.cpl)) {
nvme_printf(ctrlr, "nvme_identify_controller failed!\n");
@ -431,10 +431,10 @@ nvme_ctrlr_set_num_qpairs(struct nvme_controller *ctrlr)
struct nvme_completion_poll_status status;
int cq_allocated, sq_allocated;
status.done = FALSE;
status.done = 0;
nvme_ctrlr_cmd_set_num_queues(ctrlr, ctrlr->num_io_queues,
nvme_completion_poll_cb, &status);
while (status.done == FALSE)
while (!atomic_load_acq_int(&status.done))
pause("nvme", 1);
if (nvme_completion_is_error(&status.cpl)) {
nvme_printf(ctrlr, "nvme_ctrlr_set_num_qpairs failed!\n");
@ -470,20 +470,20 @@ nvme_ctrlr_create_qpairs(struct nvme_controller *ctrlr)
for (i = 0; i < ctrlr->num_io_queues; i++) {
qpair = &ctrlr->ioq[i];
status.done = FALSE;
status.done = 0;
nvme_ctrlr_cmd_create_io_cq(ctrlr, qpair, qpair->vector,
nvme_completion_poll_cb, &status);
while (status.done == FALSE)
while (!atomic_load_acq_int(&status.done))
pause("nvme", 1);
if (nvme_completion_is_error(&status.cpl)) {
nvme_printf(ctrlr, "nvme_create_io_cq failed!\n");
return (ENXIO);
}
status.done = FALSE;
status.done = 0;
nvme_ctrlr_cmd_create_io_sq(qpair->ctrlr, qpair,
nvme_completion_poll_cb, &status);
while (status.done == FALSE)
while (!atomic_load_acq_int(&status.done))
pause("nvme", 1);
if (nvme_completion_is_error(&status.cpl)) {
nvme_printf(ctrlr, "nvme_create_io_sq failed!\n");
@ -693,10 +693,10 @@ nvme_ctrlr_configure_aer(struct nvme_controller *ctrlr)
ctrlr->async_event_config.raw = 0xFF;
ctrlr->async_event_config.bits.reserved = 0;
status.done = FALSE;
status.done = 0;
nvme_ctrlr_cmd_get_feature(ctrlr, NVME_FEAT_TEMPERATURE_THRESHOLD,
0, NULL, 0, nvme_completion_poll_cb, &status);
while (status.done == FALSE)
while (!atomic_load_acq_int(&status.done))
pause("nvme", 1);
if (nvme_completion_is_error(&status.cpl) ||
(status.cpl.cdw0 & 0xFFFF) == 0xFFFF ||

2
sys/dev/nvme/nvme_private.h
View File

@ -128,7 +128,7 @@ extern int32_t nvme_retry_count;
struct nvme_completion_poll_status {
struct nvme_completion cpl;
boolean_t done;
int done;
};
#define NVME_REQUEST_VADDR 1