[Devel] [RFC PATCH vz9 v5 12/49] dm-ploop: WIP move from wq to kthread
Alexander Atanasov
alexander.atanasov at virtuozzo.com
Mon Nov 18 09:24:39 MSK 2024
This is a base for moving to multithreaded model.
https://virtuozzo.atlassian.net/browse/VSTOR-91821
Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
---
drivers/md/dm-ploop-map.c | 65 ++++++++++++++++++++++++++++++++----
drivers/md/dm-ploop-target.c | 60 +++++++++++++++++++++++++++++++++
drivers/md/dm-ploop.h | 10 ++++++
3 files changed, 128 insertions(+), 7 deletions(-)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 83b4b8148b10..7acb86ad8b46 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -337,6 +337,16 @@ static int ploop_split_pio_to_list(struct ploop *ploop, struct pio *pio,
}
ALLOW_ERROR_INJECTION(ploop_split_pio_to_list, ERRNO);
+#define USE_KTHREAD
+static void ploop_schedule_work(struct ploop *ploop)
+{
+#ifndef USE_KTHREAD
+ queue_work(ploop->wq, &ploop->worker);
+#else
+ wake_up_process(ploop->kt_worker->task);
+#endif
+}
+
static void ploop_dispatch_pio(struct ploop *ploop, struct pio *pio)
{
struct llist_head *list = (struct llist_head *)&ploop->pios[pio->queue_list_id];
@@ -360,7 +370,7 @@ void ploop_dispatch_pios(struct ploop *ploop, struct pio *pio,
ploop_dispatch_pio(ploop, pio);
}
- queue_work(ploop->wq, &ploop->worker);
+ ploop_schedule_work(ploop);
}
static bool ploop_delay_if_md_busy(struct ploop *ploop, struct md_page *md,
@@ -692,7 +702,7 @@ static void ploop_complete_cow(struct ploop_cow *cow, blk_status_t bi_status)
ploop_queue_or_fail(ploop, blk_status_to_errno(bi_status), cow_pio);
- queue_work(ploop->wq, &ploop->worker);
+ ploop_schedule_work(ploop);
ploop_free_pio_with_pages(ploop, cow->aux_pio);
kmem_cache_free(cow_cache, cow);
}
@@ -1141,7 +1151,7 @@ static void ploop_queue_resubmit(struct pio *pio)
llist_add((struct llist_node *)(&pio->list), &ploop->llresubmit_pios);
- queue_work(ploop->wq, &ploop->worker);
+ ploop_schedule_work(ploop);
}
static void ploop_check_standby_mode(struct ploop *ploop, long res)
@@ -1813,9 +1823,8 @@ static void process_ploop_fsync_work(struct ploop *ploop)
}
}
-void do_ploop_work(struct work_struct *ws)
+void do_ploop_run_work(struct ploop *ploop)
{
- struct ploop *ploop = container_of(ws, struct ploop, worker);
LIST_HEAD(deferred_pios);
struct llist_node *llembedded_pios;
struct llist_node *lldeferred_pios;
@@ -1827,12 +1836,14 @@ void do_ploop_work(struct work_struct *ws)
current->flags |= PF_IO_THREAD|PF_LOCAL_THROTTLE|PF_MEMALLOC_NOIO;
llembedded_pios = llist_del_all(&ploop->pios[PLOOP_LIST_PREPARE]);
+ smp_wmb();
+
lldeferred_pios = llist_del_all(&ploop->pios[PLOOP_LIST_DEFERRED]);
lldiscard_pios = llist_del_all(&ploop->pios[PLOOP_LIST_DISCARD]);
llcow_pios = llist_del_all(&ploop->pios[PLOOP_LIST_COW]);
llresubmit = llist_del_all(&ploop->llresubmit_pios);
- /* add old deferred to the list */
+ /* add old deferred back to the list */
if (lldeferred_pios) {
struct llist_node *pos, *t;
struct pio *pio;
@@ -1864,6 +1875,46 @@ void do_ploop_work(struct work_struct *ws)
current->flags = old_flags;
}
+void do_ploop_work(struct work_struct *ws)
+{
+ struct ploop *ploop = container_of(ws, struct ploop, worker);
+ do_ploop_run_work(ploop);
+}
+
+int ploop_worker(void *data)
+{
+ struct ploop_worker *worker = data;
+ struct ploop *ploop = worker->ploop;
+
+ for (;;) {
+ set_current_state(TASK_INTERRUPTIBLE);
+
+ if (kthread_should_stop()) {
+ __set_current_state(TASK_RUNNING);
+ break;
+ }
+#ifdef USE_KTHREAD
+ smp_rmb();
+ if (llist_empty(&ploop->pios[PLOOP_LIST_FLUSH]) &&
+ llist_empty(&ploop->pios[PLOOP_LIST_PREPARE]) &&
+ llist_empty(&ploop->pios[PLOOP_LIST_DEFERRED]) &&
+ llist_empty(&ploop->pios[PLOOP_LIST_DISCARD]) &&
+ llist_empty(&ploop->pios[PLOOP_LIST_COW]) &&
+ llist_empty(&ploop->llresubmit_pios)
+ )
+ schedule();
+
+ __set_current_state(TASK_RUNNING);
+ do_ploop_run_work(ploop);
+ cond_resched();
+#else
+ schedule(); // just do nothing yet
+#endif
+ }
+ return 0;
+
+}
+
static void ploop_submit_embedded_pio(struct ploop *ploop, struct pio *pio)
{
struct ploop_rq *prq = pio->endio_cb_data;
@@ -1888,7 +1939,7 @@ static void ploop_submit_embedded_pio(struct ploop *ploop, struct pio *pio)
out:
if (queue)
- queue_work(ploop->wq, &ploop->worker);
+ ploop_schedule_work(ploop);
}
void ploop_submit_embedded_pios(struct ploop *ploop, struct list_head *list)
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index ea9af6b6abe9..06a429a23302 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -166,6 +166,28 @@ static void ploop_destroy(struct ploop *ploop)
destroy_workqueue(ploop->wq);
WARN_ON_ONCE(ploop_has_pending_activity(ploop));
}
+
+ if (ploop->kt_worker) {
+ wake_up_process(ploop->kt_worker->task);
+ // FIXME: a better way to wait for lists to drain
+ /* try to send all pending - if we have partial io and enospc end bellow */
+ while(!llist_empty(&ploop->pios[PLOOP_LIST_FLUSH]) ||
+ !llist_empty(&ploop->pios[PLOOP_LIST_PREPARE]) ||
+ !llist_empty(&ploop->pios[PLOOP_LIST_DEFERRED]) ||
+ !llist_empty(&ploop->pios[PLOOP_LIST_DISCARD]) ||
+ !llist_empty(&ploop->pios[PLOOP_LIST_COW])
+ ) {
+ schedule();
+ smp_rmb();
+ }
+
+ kthread_stop(ploop->kt_worker->task); /* waits for the thread to stop */
+ WARN_ON(!llist_empty(&ploop->pios[PLOOP_LIST_PREPARE]));
+ WARN_ON(!llist_empty(&ploop->llresubmit_pios));
+ // TODO: check if any pios left and end them with error
+ kfree(ploop->kt_worker);
+ }
+
for (i = 0; i < 2; i++)
percpu_ref_exit(&ploop->inflight_bios_ref[i]);
/* Nobody uses it after destroy_workqueue() */
@@ -330,6 +352,39 @@ ALLOW_ERROR_INJECTION(ploop_add_deltas_stack, ERRNO);
argc--; \
argv++; \
} while (0);
+
+static struct ploop_worker *ploop_worker_create(struct ploop *ploop)
+{
+ struct ploop_worker *worker;
+ struct task_struct *task;
+
+ worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT);
+ if (!worker)
+ return NULL;
+
+ worker->ploop = ploop;
+ task = kthread_create(ploop_worker, worker, "ploop-%d-0",
+ current->pid);
+
+ if (IS_ERR(task))
+ goto out_err;
+ worker->task = task;
+
+ wake_up_process(task);
+ // TODO: handle cgroups
+ // ret = ploop_attach_cgroups(worker);
+ // if (ret)
+ // goto stop_worker;
+
+ return worker;
+
+// stop_worker:
+// kthread_stop(worker->task);
+out_err:
+ kfree(worker);
+ return NULL;
+}
+#endif
/*
* <data dev>
*/
@@ -474,6 +529,11 @@ static int ploop_ctr(struct dm_target *ti, unsigned int argc, char **argv)
if (argc <= 0)
goto err;
+
+ ploop->kt_worker = ploop_worker_create(ploop);
+ if (!ploop->kt_worker)
+ goto err;
+
ret = ploop_add_deltas_stack(ploop, &argv[0], argc);
if (ret)
goto err;
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index bd4906e4c2b5..803f3f324550 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -139,6 +139,12 @@ enum {
PLOOP_LIST_INVALID = PLOOP_LIST_COUNT,
};
+struct ploop_worker {
+ struct ploop *ploop;
+ struct task_struct *task;
+ u64 kcov_handle;
+};
+
struct ploop {
struct dm_target *ti;
#define PLOOP_PRQ_POOL_SIZE 512 /* Twice nr_requests from blk_mq_init_sched() */
@@ -184,6 +190,7 @@ struct ploop {
struct work_struct worker;
struct work_struct event_work;
+ struct ploop_worker *kt_worker;
struct completion inflight_bios_ref_comp;
struct percpu_ref inflight_bios_ref[2];
bool inflight_ref_comp_pending;
@@ -599,4 +606,7 @@ extern void ploop_call_rw_iter(struct file *file, loff_t pos, unsigned rw,
struct iov_iter *iter, struct pio *pio);
extern void ploop_enospc_timer(struct timer_list *timer);
extern loff_t ploop_llseek_hole(struct dm_target *ti, loff_t offset, int whence);
+
+int ploop_worker(void *data);
+
#endif /* __DM_PLOOP_H */
--
2.43.0
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