[Devel] [PATCH vz9 v2 25/65] dm-ploop: add delay for metadata writeback
Konstantin Khorenko
khorenko at virtuozzo.com
Wed Feb 12 12:33:18 MSK 2025
From: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
Revert llist conversion for metadata writeback.
Create new list for priority metadata updates, which are triggered
by FUA requests.
Write metadata for all other requests in batch after some delay.
Add new parameter to specify delay time.
Always submit COW and discard io to prio list.
https://virtuozzo.atlassian.net/browse/VSTOR-91817
Signed-off-by: Andrey Zhadchenko <andrey.zhadchenko 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-bat.c | 2 ++
drivers/md/dm-ploop-map.c | 66 ++++++++++++++++++++++++++++++------
drivers/md/dm-ploop-target.c | 13 +++++++
drivers/md/dm-ploop.h | 10 +++++-
4 files changed, 80 insertions(+), 11 deletions(-)
diff --git a/drivers/md/dm-ploop-bat.c b/drivers/md/dm-ploop-bat.c
index 96ba099b1ca4..33069d580e87 100644
--- a/drivers/md/dm-ploop-bat.c
+++ b/drivers/md/dm-ploop-bat.c
@@ -88,7 +88,9 @@ static struct md_page *ploop_alloc_md_page(u32 id)
md->page = page;
md->kmpage = kmap(page);
md->id = id;
+ md->high_prio = false;
spin_lock_init(&md->md_lock);
+
return md;
err_page:
kfree(levels);
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 46e1afbdad32..88e128bba479 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -553,17 +553,39 @@ static void ploop_unlink_completed_pio(struct ploop *ploop, struct pio *pio)
static bool ploop_md_make_dirty(struct ploop *ploop, struct md_page *md)
{
+ unsigned long flags;
bool new = false;
+ write_lock_irqsave(&ploop->bat_rwlock, flags);
WARN_ON_ONCE(test_bit(MD_WRITEBACK, &md->status));
if (!test_and_set_bit(MD_DIRTY, &md->status)) {
- llist_add(&md->wb_llink, &ploop->wb_batch_llist);
+ list_add(&md->wb_link, &ploop->wb_batch_list);
new = true;
}
-
+ write_unlock_irqrestore(&ploop->bat_rwlock, flags);
return new;
}
+static void ploop_md_up_prio(struct ploop *ploop, struct md_page *md)
+{
+ unsigned long flags;
+
+ write_lock_irqsave(&ploop->bat_rwlock, flags);
+ if (test_bit(MD_WRITEBACK, &md->status))
+ goto out;
+ if (md->high_prio)
+ goto out;
+
+ md->high_prio = true;
+ WARN_ON_ONCE(!test_bit(MD_DIRTY, &md->status));
+
+ list_del(&md->wb_link);
+ list_add(&md->wb_link, &ploop->wb_batch_list_prio);
+
+out:
+ write_unlock_irqrestore(&ploop->bat_rwlock, flags);
+}
+
static bool ploop_pio_endio_if_all_zeros(struct pio *pio)
{
struct bvec_iter bi = {
@@ -1421,6 +1443,8 @@ static void ploop_submit_cow_index_wb(struct ploop_cow *cow)
WRITE_ONCE(md->bat_levels[clu], ploop_top_level(ploop));
spin_unlock_irqrestore(&md->md_lock, flags);
+ ploop_md_up_prio(ploop, md);
+
/* Prevent double clearing of holes_bitmap bit on complete_cow() */
cow->dst_clu = BAT_ENTRY_NONE;
spin_lock_irq(&ploop->deferred_lock);
@@ -1518,6 +1542,7 @@ static bool ploop_locate_new_cluster_and_attach_pio(struct ploop *ploop,
if (pio->bi_op & REQ_FUA) {
piwb->pio->bi_op |= REQ_FUA;
ploop_attach_end_action(pio, piwb);
+ ploop_md_up_prio(ploop, md);
}
attached = true;
@@ -1760,6 +1785,7 @@ static void ploop_process_one_discard_pio(struct ploop *ploop, struct pio *pio)
if (bat_update_prepared)
ploop_md_make_dirty(ploop, md);
+ ploop_md_up_prio(ploop, md);
out:
return;
err:
@@ -1795,25 +1821,45 @@ static void ploop_process_resubmit_pios(struct ploop *ploop,
}
}
-static void ploop_submit_metadata_writeback(struct ploop *ploop)
+static void ploop_submit_metadata_writeback_from_list(struct ploop *ploop,
+ struct list_head *list)
{
struct md_page *md;
- struct md_page *t;
- struct llist_node *wbl;
- wbl = llist_del_all(&ploop->wb_batch_llist);
- if (!wbl)
- return;
- wbl = llist_reverse_order(wbl);
- llist_for_each_entry_safe(md, t, wbl, wb_llink) {
+ while (1) {
+ write_lock_irq(&ploop->bat_rwlock);
+ md = list_first_entry_or_null(list, struct md_page, wb_link);
+ if (!md) {
+ write_unlock_irq(&ploop->bat_rwlock);
+ break;
+ }
+ list_del_init(&md->wb_link);
+ /* L1L2 mustn't be redirtyed, when wb in-flight! */
+
WARN_ON_ONCE(!test_bit(MD_DIRTY, &md->status));
WARN_ON_ONCE(test_bit(MD_WRITEBACK, &md->status));
set_bit(MD_WRITEBACK, &md->status);
clear_bit(MD_DIRTY, &md->status);
+ md->high_prio = false;
+ write_unlock_irq(&ploop->bat_rwlock);
+
ploop_index_wb_submit(ploop, md->piwb);
}
}
+static void ploop_submit_metadata_writeback(struct ploop *ploop)
+{
+ ktime_t time;
+
+ ploop_submit_metadata_writeback_from_list(ploop, &ploop->wb_batch_list_prio);
+
+ time = ktime_get();
+ if (ktime_after(time, ktime_add_ms(ploop->last_md_submit, ploop->md_submit_delay_ms))) {
+ ploop->last_md_submit = time;
+ ploop_submit_metadata_writeback_from_list(ploop, &ploop->wb_batch_list);
+ }
+}
+
static void process_ploop_fsync_work(struct ploop *ploop, struct llist_node *llflush_pios)
{
struct file *file;
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index 00d160b3fd3c..f714c2cb540f 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -422,6 +422,11 @@ static int ploop_ctr(struct dm_target *ti, unsigned int argc, char **argv)
INIT_LIST_HEAD(&ploop->cluster_lk_list);
init_llist_head(&ploop->wb_batch_llist);
+ INIT_LIST_HEAD(&ploop->wb_batch_list);
+ INIT_LIST_HEAD(&ploop->wb_batch_list_prio);
+ ploop->last_md_submit = 0;
+ ploop->md_submit_delay_ms = PLOOP_DEFAULT_METADATA_SUBMIT_DELAY;
+
ploop->bat_entries = RB_ROOT;
timer_setup(&ploop->enospc_timer, ploop_enospc_timer, 0);
@@ -503,6 +508,14 @@ static int ploop_ctr(struct dm_target *ti, unsigned int argc, char **argv)
EAT_ARG(argc, argv);
continue;
}
+#define PLOOP_MD_DELAY_ARG "metadata_delay="
+ if (strncmp(argv[0], PLOOP_MD_DELAY_ARG, sizeof(PLOOP_MD_DELAY_ARG) - 1) == 0) {
+ if (kstrtou64(argv[0] + sizeof(PLOOP_MD_DELAY_ARG) - 1, 10,
+ &ploop->md_submit_delay_ms) < 0)
+ goto err;
+ EAT_ARG(argc, argv);
+ continue;
+ }
break;
}
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index 6bf8b85a85c0..0ea73b4289e2 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -122,10 +122,12 @@ struct md_page {
u8 *bat_levels;
struct llist_head wait_llist;
- struct llist_node wb_llink;
+ struct list_head wb_link;
struct ploop_index_wb *piwb;
spinlock_t md_lock;
+
+ bool high_prio;
};
enum {
@@ -174,6 +176,12 @@ struct ploop {
rwlock_t bat_rwlock;
struct llist_head wb_batch_llist;
+ struct list_head wb_batch_list;
+ struct list_head wb_batch_list_prio;
+
+ ktime_t last_md_submit;
+#define PLOOP_DEFAULT_METADATA_SUBMIT_DELAY 10000
+ uint64_t md_submit_delay_ms;
/*
* Hash table to link non-exclusive submitted bios.
--
2.43.5
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