[Devel] [PATCH RHEL9 COMMIT] dm-ploop: rework bat completion logic
Konstantin Khorenko
khorenko at virtuozzo.com
Mon Jan 27 16:12:53 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 050030db3438c01f105d4904a73d615a7dc124c8
Author: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
Date: Fri Jan 24 17:36:29 2025 +0200
dm-ploop: rework bat completion logic
a pio may complete after md page update, in that case we
must not complete the update but wait for the last data pio
and only then complete them all.
https://virtuozzo.atlassian.net/browse/VSTOR-91821
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-map.c | 105 ++++++++++++++++++++++++----------------------
1 file changed, 54 insertions(+), 51 deletions(-)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 7d5e2cf443ee..35d12fd54050 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -21,6 +21,8 @@
#include "dm-rq.h"
static inline int ploop_runners_add_work(struct ploop *ploop, struct pio *pio);
+static void ploop_bat_write_complete(struct pio *pio, void *piwb_ptr,
+ blk_status_t bi_status);
#define PREALLOC_SIZE (128ULL * 1024 * 1024)
@@ -900,6 +902,7 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
if (wait_llist_pending) {
llist_for_each_safe(pos, t, wait_llist_pending) {
pio = list_entry((struct list_head *)pos, typeof(*pio), list);
+ INIT_LIST_HEAD(&pio->list);
list_add(&pio->list, &list);
}
}
@@ -915,28 +918,31 @@ static void ploop_free_piwb(struct ploop_index_wb *piwb)
kfree(piwb);
}
+
+static void ploop_bat_write_finish(struct pio *pio, void *piwb_ptr,
+ blk_status_t bi_status);
static void ploop_put_piwb(struct ploop_index_wb *piwb)
{
if (atomic_dec_and_test(&piwb->count)) {
- struct ploop *ploop = piwb->ploop;
- /*
- * Index wb failed. Mark clusters as unallocated again.
- * piwb->count is zero, so all data writers compeleted.
- */
- if (piwb->bi_status)
- ploop_advance_local_after_bat_wb(ploop, piwb, false);
+
+ ploop_bat_write_finish(piwb->pio, piwb, piwb->bi_status);
if (piwb->comp) {
if (piwb->comp_bi_status)
*piwb->comp_bi_status = piwb->bi_status;
complete(piwb->comp);
}
+ /*
+ * Status is set from first call to ploop_bat_write_complete
+ * zero keeps it as is
+ */
+
ploop_free_piwb(piwb);
}
}
/* This handler is called after BAT is updated. */
-static void ploop_bat_write_complete(struct pio *pio, void *piwb_ptr,
+static void ploop_bat_write_finish(struct pio *pio, void *piwb_ptr,
blk_status_t bi_status)
{
struct ploop_index_wb *piwb = piwb_ptr;
@@ -950,30 +956,30 @@ static void ploop_bat_write_complete(struct pio *pio, void *piwb_ptr,
struct llist_node *pos, *t;
struct llist_node *ll_cow_pios;
struct llist_node *ll_ready_pios;
- int completed = atomic_read(&piwb->count) == 1;
-
- if (completed) {
- /* We are the last count so it is safe to advance bat */
- if (!bi_status) {
- /*
- * Success: now update local BAT copy. We could do this
- * from our delayed work, but we want to publish new
- * mapping in the fastest way. This must be done before
- * data bios completion, since right after we complete
- * a bio, subsequent read wants to see written data
- * (ploop_map() wants to see not zero bat_entries[.]).
- */
- ploop_advance_local_after_bat_wb(ploop, piwb, true);
- }
+
+ if (!bi_status) {
+ /*
+ * Success: now update local BAT copy. We could do this
+ * from our delayed work, but we want to publish new
+ * mapping in the fastest way. This must be done before
+ * data bios completion, since right after we complete
+ * a bio, subsequent read wants to see written data
+ * (ploop_map() wants to see not zero bat_entries[.]).
+ */
+ ploop_advance_local_after_bat_wb(ploop, piwb, true);
+ } else {
+ /*
+ * Index wb failed. Mark clusters as unallocated again.
+ * piwb->count is zero, so all data writers compeleted.
+ */
+ ploop_advance_local_after_bat_wb(ploop, piwb, false);
}
spin_lock_irqsave(&piwb->lock, flags);
- if (completed)
- piwb->completed = completed;
- piwb->bi_status = bi_status;
- ll_ready_pios = llist_reverse_order(llist_del_all(&piwb->llready_data_pios));
+ ll_ready_pios = llist_del_all(&piwb->llready_data_pios);
+ if (bi_status)
+ piwb->bi_status = bi_status;
spin_unlock_irqrestore(&piwb->lock, flags);
-
ll_cow_pios = llist_reverse_order(llist_del_all(&piwb->cow_llist));
/*
@@ -981,8 +987,8 @@ static void ploop_bat_write_complete(struct pio *pio, void *piwb_ptr,
*/
llist_for_each_safe(pos, t, ll_ready_pios) {
- pio = list_entry((struct list_head *)pos, typeof(*aux_pio), list);
- INIT_LIST_HEAD(&pio->list);
+ data_pio = list_entry((struct list_head *)pos, typeof(*data_pio), list);
+ INIT_LIST_HEAD(&data_pio->list);
if (bi_status)
data_pio->bi_status = bi_status;
ploop_pio_endio(data_pio);
@@ -1000,11 +1006,17 @@ static void ploop_bat_write_complete(struct pio *pio, void *piwb_ptr,
ploop_dispatch_pios(ploop, flush_pio, NULL);
piwb->flush_pio = NULL;
}
+}
+
+static void ploop_bat_write_complete(struct pio *pio, void *piwb_ptr,
+ blk_status_t bi_status)
+
+{
+ struct ploop_index_wb *piwb = piwb_ptr;
+
+ if (bi_status)
+ piwb->bi_status = bi_status;
- /*
- * In case of update BAT is failed, dst_clusters will be
- * set back to holes_bitmap on last put_piwb().
- */
ploop_put_piwb(piwb);
}
@@ -1032,7 +1044,6 @@ static int ploop_prepare_bat_update(struct ploop *ploop, struct md_page *md,
if (!page || !pio)
goto err;
ploop_init_pio(ploop, REQ_OP_WRITE, pio);
-
bat_entries = md->kmpage;
spin_lock(&md->md_lock); /* write */
@@ -1260,23 +1271,19 @@ static int ploop_alloc_cluster(struct ploop *ploop, struct ploop_index_wb *piwb,
return ret;
}
-static bool ploop_data_pio_end(struct pio *pio)
+static void ploop_data_pio_end(struct pio *pio)
{
struct ploop_index_wb *piwb = pio->piwb;
unsigned long flags;
- bool completed;
spin_lock_irqsave(&piwb->lock, flags);
- completed = piwb->completed;
- if (!completed)
- llist_add((struct llist_node *)(&pio->list), &piwb->llready_data_pios);
- else if (!pio->bi_status)
+ llist_add((struct llist_node *)(&pio->list), &piwb->llready_data_pios);
+ if (!pio->bi_status)
pio->bi_status = piwb->bi_status;
- spin_unlock_irqrestore(&piwb->lock, flags);
+ /* If pio is late then end it here. this can happen with flushes */
+ spin_unlock_irqrestore(&piwb->lock, flags);
ploop_put_piwb(piwb);
-
- return completed;
}
static void ploop_attach_end_action(struct pio *pio, struct ploop_index_wb *piwb)
@@ -1320,8 +1327,6 @@ static void ploop_check_standby_mode(struct ploop *ploop, long res)
static void ploop_data_rw_complete(struct pio *pio)
{
- bool completed;
-
if (pio->ret != pio->bi_iter.bi_size) {
if (pio->ret >= 0 || pio->ret == -ENOTBLK) {
/* Partial IO or request to retry in buffered mode */
@@ -1356,12 +1361,10 @@ static void ploop_data_rw_complete(struct pio *pio)
}
check_da:
if (pio->is_data_alloc) {
- completed = ploop_data_pio_end(pio);
- if (!completed)
- return;
+ ploop_data_pio_end(pio);
+ } else {
+ ploop_pio_endio(pio);
}
-
- ploop_pio_endio(pio);
}
/*
More information about the Devel
mailing list