[Devel] [PATCH RHEL9 COMMIT] dm-ploop: convert suspended_pios list to use lockless list
Konstantin Khorenko
khorenko at virtuozzo.com
Mon Jan 27 16:12:34 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 ebabfe1a2862c4d838e365c33839c2685ea34b0e
Author: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
Date: Fri Jan 24 17:35:41 2025 +0200
dm-ploop: convert suspended_pios list to use lockless list
https://virtuozzo.atlassian.net/browse/VSTOR-91820
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-cmd.c | 14 ++++++++++++--
drivers/md/dm-ploop-map.c | 2 +-
drivers/md/dm-ploop-target.c | 2 +-
drivers/md/dm-ploop.h | 2 +-
4 files changed, 15 insertions(+), 5 deletions(-)
diff --git a/drivers/md/dm-ploop-cmd.c b/drivers/md/dm-ploop-cmd.c
index ce6204c09e92..3d9818003a08 100644
--- a/drivers/md/dm-ploop-cmd.c
+++ b/drivers/md/dm-ploop-cmd.c
@@ -124,14 +124,24 @@ ALLOW_ERROR_INJECTION(ploop_inflight_bios_ref_switch, ERRNO);
static void ploop_resume_submitting_pios(struct ploop *ploop)
{
LIST_HEAD(list);
+ struct llist_node *suspended_pending;
spin_lock_irq(&ploop->deferred_lock);
WARN_ON_ONCE(!ploop->stop_submitting_pios);
ploop->stop_submitting_pios = false;
- list_splice_tail_init(&ploop->suspended_pios, &list);
spin_unlock_irq(&ploop->deferred_lock);
- ploop_submit_embedded_pios(ploop, &list);
+ suspended_pending = llist_del_all(&ploop->llsuspended_pios);
+ if (suspended_pending) {
+ struct llist_node *pos, *t;
+
+ llist_for_each_safe(pos, t, suspended_pending) {
+ struct pio *pio = list_entry((struct list_head *)pos, typeof(*pio), list);
+
+ list_add(&pio->list, &list);
+ }
+ ploop_submit_embedded_pios(ploop, &list);
+ }
}
static int ploop_suspend_submitting_pios(struct ploop *ploop)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 08d5391aa9d3..bdc2ea214242 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -1881,7 +1881,7 @@ static void ploop_submit_embedded_pio(struct ploop *ploop, struct pio *pio)
spin_lock_irqsave(&ploop->deferred_lock, flags);
if (unlikely(ploop->stop_submitting_pios)) {
- list_add_tail(&pio->list, &ploop->suspended_pios);
+ llist_add((struct llist_node *)(&pio->list), &ploop->llsuspended_pios);
queue = false;
goto unlock;
}
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index 3ac9e1f832f5..94d6f661f50c 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -370,7 +370,7 @@ static int ploop_ctr(struct dm_target *ti, unsigned int argc, char **argv)
spin_lock_init(&ploop->inflight_lock);
spin_lock_init(&ploop->deferred_lock);
- INIT_LIST_HEAD(&ploop->suspended_pios);
+ init_llist_head(&ploop->llsuspended_pios);
for (i = 0; i < PLOOP_LIST_COUNT; i++)
INIT_LIST_HEAD(&ploop->pios[i]);
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index da5d8cfcf8ca..676476bbf655 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -189,7 +189,7 @@ struct ploop {
bool inflight_ref_comp_pending;
unsigned int inflight_bios_ref_index:1;
- struct list_head suspended_pios;
+ struct llist_head llsuspended_pios;
bool stop_submitting_pios;
spinlock_t inflight_lock;
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