From: Alexander Atanasov <alexander.atana...@virtuozzo.com> reduce locking for cow pios chained to bat updates
https://virtuozzo.atlassian.net/browse/VSTOR-91821 Signed-off-by: Alexander Atanasov <alexander.atana...@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 | 19 ++++++++++--------- drivers/md/dm-ploop.h | 2 +- 2 files changed, 11 insertions(+), 10 deletions(-) diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c index a4ad1f626001..ea2058b75962 100644 --- a/drivers/md/dm-ploop-map.c +++ b/drivers/md/dm-ploop-map.c @@ -63,7 +63,8 @@ void ploop_index_wb_init(struct ploop_index_wb *piwb, struct ploop *ploop) piwb->bat_page = NULL; piwb->bi_status = 0; INIT_LIST_HEAD(&piwb->ready_data_pios); - INIT_LIST_HEAD(&piwb->cow_list); + init_llist_head(&piwb->cow_llist); + /* For ploop_bat_write_complete() */ atomic_set(&piwb->count, 1); piwb->completed = false; @@ -901,7 +902,8 @@ static void ploop_bat_write_complete(struct pio *pio, void *piwb_ptr, struct pio *data_pio; unsigned long flags; LIST_HEAD(lready_pios); - LIST_HEAD(lcow_pios); + struct llist_node *pos, *t; + struct llist_node *ll_cow_pios; int completed = atomic_read(&piwb->count) == 1; if (completed) { @@ -926,9 +928,7 @@ static void ploop_bat_write_complete(struct pio *pio, void *piwb_ptr, list_splice_init(&piwb->ready_data_pios, &lready_pios); spin_unlock_irqrestore(&piwb->lock, flags); - spin_lock_irqsave(&ploop->deferred_lock, flags); - list_splice_init(&piwb->cow_list, &lcow_pios); - spin_unlock_irqrestore(&ploop->deferred_lock, flags); + ll_cow_pios = llist_reverse_order(llist_del_all(&piwb->cow_llist)); /* * End pending data bios. @@ -940,7 +940,9 @@ static void ploop_bat_write_complete(struct pio *pio, void *piwb_ptr, ploop_pio_endio(data_pio); } - while ((aux_pio = ploop_pio_list_pop(&lcow_pios))) { + llist_for_each_safe(pos, t, ll_cow_pios) { + aux_pio = llist_entry(pos, typeof(*aux_pio), llist); + INIT_LIST_HEAD(&aux_pio->list); cow = aux_pio->endio_cb_data; ploop_complete_cow(cow, bi_status); } @@ -1508,9 +1510,8 @@ static void ploop_submit_cow_index_wb(struct ploop_cow *cow) #endif /* Prevent double clearing of holes_bitmap bit on complete_cow() */ cow->dst_clu = BAT_ENTRY_NONE; - spin_lock_irq(&ploop->deferred_lock); - list_add_tail(&cow->aux_pio->list, &piwb->cow_list); - spin_unlock_irq(&ploop->deferred_lock); + + llist_add(&cow->aux_pio->llist, &piwb->cow_llist); out: return; err_resource: diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h index f40a2220055b..2e1b2044dcbd 100644 --- a/drivers/md/dm-ploop.h +++ b/drivers/md/dm-ploop.h @@ -102,7 +102,7 @@ struct ploop_index_wb { struct pio *pio; struct page *bat_page; struct list_head ready_data_pios; - struct list_head cow_list; + struct llist_head cow_llist; atomic_t count; bool completed; blk_status_t bi_status; -- 2.43.5 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel
