[Devel] [PATCH RHEL9 COMMIT] dm-ploop: end fsync pios in parallel
Konstantin Khorenko
khorenko at virtuozzo.com
Mon Jan 27 16:12:54 MSK 2025
The commit is pushed to "branch-rh9-5.14.0-427.44.1.vz9.80.x-ovz" and will appear at git at bitbucket.org:openvz/vzkernel.git
after rh9-5.14.0-427.44.1.vz9.80.6
------>
commit f68f8ecb535c9b780e85d1f9c6f0e6b74bb38c0e
Author: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
Date: Fri Jan 24 17:36:31 2025 +0200
dm-ploop: end fsync pios in parallel
Send all pios attached to sync operation to runners
to call endio.
https://virtuozzo.atlassian.net/browse/VSTOR-91821
Signed-off-by: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
======
Patchset description:
ploop: optimistations and scalling
Ploop processes requsts in a different threads in parallel
where possible which results in significant improvement in
performance and makes further optimistations possible.
Known bugs:
- delayed metadata writeback is not working and is missing error handling
- patch to disable it until fixed
- fast path is not working - causes rcu lockups - patch to disable it
Further improvements:
- optimize md pages lookups
Alexander Atanasov (50):
dm-ploop: md_pages map all pages at creation time
dm-ploop: Use READ_ONCE/WRITE_ONCE to access md page data
dm-ploop: fsync after all pios are sent
dm-ploop: move md status to use proper bitops
dm-ploop: convert wait_list and wb_batch_llist to use lockless lists
dm-ploop: convert enospc handling to use lockless lists
dm-ploop: convert suspended_pios list to use lockless list
dm-ploop: convert the rest of the lists to use llist variant
dm-ploop: combine processing of pios thru prepare list and remove
fsync worker
dm-ploop: move from wq to kthread
dm-ploop: move preparations of pios into the caller from worker
dm-ploop: fast path execution for reads
dm-ploop: do not use a wrapper for set_bit to make a page writeback
dm-ploop: BAT use only one list for writeback
dm-ploop: make md writeback timeout to be per page
dm-ploop: add interface to disable bat writeback delay
dm-ploop: convert wb_batch_list to lockless variant
dm-ploop: convert high_prio to status
dm-ploop: split cow processing into two functions
dm-ploop: convert md page rw lock to spin lock
dm-ploop: convert bat_rwlock to bat_lock spinlock
dm-ploop: prepare bat updates under bat_lock
dm-ploop: make ploop_bat_write_complete ready for parallel pio
completion
dm-ploop: make ploop_submit_metadata_writeback return number of
requests sent
dm-ploop: introduce pio runner threads
dm-ploop: add pio list ids to be used when passing pios to runners
dm-ploop: process pios via runners
dm-ploop: disable metadata writeback delay
dm-ploop: disable fast path
dm-ploop: use lockless lists for chained cow updates list
dm-ploop: use lockless lists for data ready pios
dm-ploop: give runner threads better name
dm-ploop: resize operation - add holes bitmap locking
dm-ploop: remove unnecessary operations
dm-ploop: use filp per thread
dm-ploop: catch if we try to advance pio past bio end
dm-ploop: support REQ_FUA for data pios
dm-ploop: proplerly access nr_bat_entries
dm-ploop: fix locking and improve error handling when submitting pios
dm-ploop: fix how ENOTBLK is handled
dm-ploop: sync when suspended or stopping
dm-ploop: rework bat completion logic
dm-ploop: rework logic in pio processing
dm-ploop: end fsync pios in parallel
dm-ploop: make filespace preallocations async
dm-ploop: resubmit enospc pios from dispatcher thread
dm-ploop: dm-ploop: simplify discard completion
dm-ploop: use GFP_ATOMIC instead of GFP_NOIO
dm-ploop: fix locks used in mixed context
dm-ploop: fix how current flags are managed inside threads
Andrey Zhadchenko (13):
dm-ploop: do not flush after metadata writes
dm-ploop: set IOCB_DSYNC on all FUA requests
dm-ploop: remove extra ploop_cluster_is_in_top_delta()
dm-ploop: introduce per-md page locking
dm-ploop: reduce BAT accesses on discard completion
dm-ploop: simplify llseek
dm-ploop: speed up ploop_prepare_bat_update()
dm-ploop: make new allocations immediately visible in BAT
dm-ploop: drop ploop_cluster_is_in_top_delta()
dm-ploop: do not wait for BAT update for non-FUA requests
dm-ploop: add delay for metadata writeback
dm-ploop: submit all postponed metadata on REQ_OP_FLUSH
dm-ploop: handle REQ_PREFLUSH
Feature: dm-ploop: ploop target driver
---
drivers/md/dm-ploop-map.c | 18 ++++++++++++------
drivers/md/dm-ploop-target.c | 1 +
drivers/md/dm-ploop.h | 2 ++
3 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index f9904e708c35..cb25255e5bf4 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -2006,7 +2006,10 @@ static int process_ploop_fsync_work(struct ploop *ploop, struct llist_node *llfl
if (static_branch_unlikely(&ploop_standby_check))
ploop_check_standby_mode(ploop, ret);
}
- ploop_pio_endio(pio);
+ pio->queue_list_id = PLOOP_LIST_FLUSHPIO;
+ atomic_inc(&ploop->kt_worker->fsync_pios);
+ ploop_runners_add_work(ploop, pio);
+ npios++;
}
return npios;
}
@@ -2105,14 +2108,12 @@ void do_ploop_run_work(struct ploop *ploop)
/* Now process fsync pios after we have done all other */
npios = process_ploop_fsync_work(ploop, llflush_pios);
/* Since dispatcher is single thread no other work can be queued */
-#ifdef USE_RUNNERS__NOT_READY
if (npios) {
current->flags = old_flags;
wait_event_interruptible(ploop->dispatcher_wq_fsync,
- atomic_read(&wrkr->fsync_pios) != 0);
+ !atomic_read(&ploop->kt_worker->fsync_pios));
current->flags |= PF_IO_THREAD|PF_LOCAL_THROTTLE|PF_MEMALLOC_NOIO;
}
-#endif
}
current->flags = old_flags;
@@ -2134,6 +2135,7 @@ int ploop_pio_runner(void *data)
struct llist_node *pos, *t;
unsigned int old_flags = current->flags;
int did_process_pios = 0;
+ int did_process_fsync = 0;
for (;;) {
current->flags = old_flags;
@@ -2146,6 +2148,10 @@ int ploop_pio_runner(void *data)
did_process_pios = 0;
wake_up_interruptible(&ploop->dispatcher_wq_data);
}
+ if (did_process_fsync) {
+ did_process_fsync = 0;
+ wake_up_interruptible(&ploop->dispatcher_wq_fsync);
+ }
/* Only stop when there is no more pios */
if (kthread_should_stop()) {
__set_current_state(TASK_RUNNING);
@@ -2170,9 +2176,9 @@ int ploop_pio_runner(void *data)
WARN_ON_ONCE(1); /* We must not see prepares here */
break;
case PLOOP_LIST_FLUSHPIO:
- // fsync pios can come here for endio
- // XXX: make it a FSYNC list
+ did_process_fsync++;
ploop_pio_endio(pio);
+ atomic_dec(&ploop->kt_worker->fsync_pios);
break;
case PLOOP_LIST_DEFERRED:
ploop_process_one_deferred_bio(ploop, pio);
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index 8b0d2b7ae85b..61190f2f7eae 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -558,6 +558,7 @@ static int ploop_ctr(struct dm_target *ti, unsigned int argc, char **argv)
init_waitqueue_head(&ploop->dispatcher_wq_data);
+ init_waitqueue_head(&ploop->dispatcher_wq_fsync);
ploop->kt_worker = ploop_worker_create(ploop, ploop_worker, "d", 0);
if (!ploop->kt_worker)
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index 11e50ab1293b..7dbe8819acf7 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -153,11 +153,13 @@ struct ploop_worker {
struct llist_head work_llist;
unsigned int runner_id;
atomic_t inflight_pios;
+ atomic_t fsync_pios;
struct ploop_worker *next;
};
struct ploop {
struct wait_queue_head dispatcher_wq_data;
+ struct wait_queue_head dispatcher_wq_fsync;
struct dm_target *ti;
#define PLOOP_PRQ_POOL_SIZE 512 /* Twice nr_requests from blk_mq_init_sched() */
mempool_t *prq_pool;
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