[Devel] [PATCH RHEL9 COMMIT] dm-ploop: reduce BAT accesses on discard completion
Konstantin Khorenko
khorenko at virtuozzo.com
Mon Jan 27 16:12:38 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 e4619ce0dfa0c683f4951e8ab8743c432a4025e1
Author: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
Date: Fri Jan 24 17:35:51 2025 +0200
dm-ploop: reduce BAT accesses on discard completion
Drop extra ploop_cluster_is_in_top_delta() as we are planning to
access BAT anyway
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-map.c | 28 ++++++++++++----------------
1 file changed, 12 insertions(+), 16 deletions(-)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 62fca243f755..119ef21323f8 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -713,12 +713,15 @@ static void ploop_complete_cow(struct ploop_cow *cow, blk_status_t bi_status)
kmem_cache_free(cow_cache, cow);
}
-static void ploop_release_cluster(struct ploop *ploop, u32 clu)
+static void ploop_piwb_discard_completed(struct ploop *ploop,
+ bool success, u32 clu, u32 new_dst_clu)
{
u32 id, *bat_entries, dst_clu;
struct md_page *md;
+ u8 level;
- lockdep_assert_held(&ploop->bat_rwlock);
+ if (new_dst_clu)
+ return;
id = ploop_bat_clu_to_page_nr(clu);
md = ploop_md_page_find(ploop, id);
@@ -728,22 +731,15 @@ static void ploop_release_cluster(struct ploop *ploop, u32 clu)
bat_entries = md->kmpage;
dst_clu = READ_ONCE(bat_entries[clu]);
- WRITE_ONCE(bat_entries[clu], BAT_ENTRY_NONE);
- WRITE_ONCE(md->bat_levels[clu], 0);
-
- ploop_hole_set_bit(dst_clu, ploop);
-}
-
-static void ploop_piwb_discard_completed(struct ploop *ploop,
- bool success, u32 clu, u32 new_dst_clu)
-{
- if (new_dst_clu)
- return;
+ level = md->bat_levels[clu];
- if (ploop_cluster_is_in_top_delta(ploop, clu)) {
+ if (!(dst_clu == BAT_ENTRY_NONE || level < ploop_top_level(ploop))) {
WARN_ON_ONCE(ploop->nr_deltas != 1);
- if (success)
- ploop_release_cluster(ploop, clu);
+ if (success) {
+ WRITE_ONCE(bat_entries[clu], BAT_ENTRY_NONE);
+ WRITE_ONCE(md->bat_levels[clu], 0);
+ ploop_hole_set_bit(dst_clu, ploop);
+ }
}
}
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