[Devel] [PATCH vz9 v2 07/65] dm-ploop: convert wait_list and wb_batch_llist to use lockless lists
Konstantin Khorenko
khorenko at virtuozzo.com
Wed Feb 12 12:33:00 MSK 2025
From: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
Convert to lockless lists - intermix with regular list due to
that next pointer in both list_head and llist_head is the first
field, and prev is not used. Do this so we can make babysteps
forward.
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
Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
---
drivers/md/dm-ploop-bat.c | 2 +-
drivers/md/dm-ploop-map.c | 50 +++++++++++++++++++-----------------
drivers/md/dm-ploop-target.c | 2 +-
drivers/md/dm-ploop.h | 6 ++---
4 files changed, 32 insertions(+), 28 deletions(-)
diff --git a/drivers/md/dm-ploop-bat.c b/drivers/md/dm-ploop-bat.c
index 02e4ddf950e3..655d0e4c91ab 100644
--- a/drivers/md/dm-ploop-bat.c
+++ b/drivers/md/dm-ploop-bat.c
@@ -80,7 +80,7 @@ static struct md_page *ploop_alloc_md_page(u32 id)
page = alloc_page(GFP_KERNEL);
if (!page)
goto err_page;
- INIT_LIST_HEAD(&md->wait_list);
+ init_llist_head(&md->wait_llist);
md->status = 0;
md->bat_levels = levels;
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index fc07d24c34a0..fa8cb0c44f8c 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -381,13 +381,14 @@ static bool ploop_delay_if_md_busy(struct ploop *ploop, struct md_page *md,
WARN_ON_ONCE(!list_empty(&pio->list));
- write_lock_irqsave(&ploop->bat_rwlock, flags);
+ /* lock protects piwb */
+ read_lock_irqsave(&ploop->bat_rwlock, flags);
piwb = md->piwb;
if (piwb && (piwb->type != type || test_bit(MD_WRITEBACK, &md->status))) {
- list_add_tail(&pio->list, &md->wait_list);
+ llist_add(&pio->llist, &md->wait_llist);
busy = true;
}
- write_unlock_irqrestore(&ploop->bat_rwlock, flags);
+ read_unlock_irqrestore(&ploop->bat_rwlock, flags);
return busy;
}
@@ -546,16 +547,13 @@ 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)) {
- list_add_tail(&md->wb_link, &ploop->wb_batch_list);
+ llist_add(&md->wb_llink, &ploop->wb_batch_llist);
new = true;
}
- write_unlock_irqrestore(&ploop->bat_rwlock, flags);
return new;
}
@@ -757,7 +755,9 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
map_index_t *dst_clu, off;
unsigned long flags;
LIST_HEAD(list);
-
+ struct llist_node *wait_llist_pending;
+ struct pio *pio;
+ struct llist_node *pos, *t;
BUG_ON(!md);
bat_entries = md->kmpage;
@@ -774,8 +774,6 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
i = PLOOP_MAP_OFFSET;
dst_clu = kmap_local_page(piwb->bat_page);
- write_lock_irqsave(&ploop->bat_rwlock, flags);
-
for (; i < last; i++) {
if (piwb->type == PIWB_TYPE_DISCARD) {
ploop_piwb_discard_completed(ploop, success, i + off, dst_clu[i]);
@@ -801,11 +799,21 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
WARN_ON_ONCE(!test_bit(MD_WRITEBACK, &md->status));
clear_bit(MD_WRITEBACK, &md->status);
+ /* protect piwb */
+ write_lock_irqsave(&ploop->bat_rwlock, flags);
md->piwb = NULL;
- list_splice_tail_init(&md->wait_list, &list);
write_unlock_irqrestore(&ploop->bat_rwlock, flags);
kunmap_local(dst_clu);
+ wait_llist_pending = llist_del_all(&md->wait_llist);
+ if (wait_llist_pending) {
+ wait_llist_pending = llist_reverse_order(wait_llist_pending);
+ llist_for_each_safe(pos, t, wait_llist_pending) {
+ pio = llist_entry(pos, typeof(*pio), llist);
+ list_add(&pio->list, &list);
+ }
+ }
+
if (!list_empty(&list))
ploop_dispatch_pios(ploop, NULL, &list);
}
@@ -1764,22 +1772,18 @@ static void ploop_process_resubmit_pios(struct ploop *ploop,
static void ploop_submit_metadata_writeback(struct ploop *ploop)
{
struct md_page *md;
- while (1) {
- write_lock_irq(&ploop->bat_rwlock);
- md = list_first_entry_or_null(&ploop->wb_batch_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! */
+ 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) {
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);
- write_unlock_irq(&ploop->bat_rwlock);
-
ploop_index_wb_submit(ploop, md->piwb);
}
}
diff --git a/drivers/md/dm-ploop-target.c b/drivers/md/dm-ploop-target.c
index 8b3b840dea66..b66ae3a9a4b0 100644
--- a/drivers/md/dm-ploop-target.c
+++ b/drivers/md/dm-ploop-target.c
@@ -378,7 +378,7 @@ static int ploop_ctr(struct dm_target *ti, unsigned int argc, char **argv)
INIT_LIST_HEAD(&ploop->resubmit_pios);
INIT_LIST_HEAD(&ploop->enospc_pios);
INIT_LIST_HEAD(&ploop->cluster_lk_list);
- INIT_LIST_HEAD(&ploop->wb_batch_list);
+ init_llist_head(&ploop->wb_batch_llist);
ploop->bat_entries = RB_ROOT;
timer_setup(&ploop->enospc_timer, ploop_enospc_timer, 0);
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index 72adeec17ed7..d459a02ded5d 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -120,9 +120,9 @@ struct md_page {
struct page *page;
void *kmpage;
u8 *bat_levels;
- struct list_head wait_list;
+ struct llist_head wait_llist;
- struct list_head wb_link;
+ struct llist_node wb_llink;
struct ploop_index_wb *piwb;
};
@@ -165,7 +165,7 @@ struct ploop {
u32 hb_nr; /* holes_bitmap size in bits */
rwlock_t bat_rwlock;
- struct list_head wb_batch_list;
+ struct llist_head wb_batch_llist;
/*
* Hash table to link non-exclusive submitted bios.
--
2.43.5
More information about the Devel
mailing list