The commit is pushed to "branch-rh9-5.14.0-427.44.1.vz9.80.x-ovz" and will
appear at g...@bitbucket.org:openvz/vzkernel.git
after rh9-5.14.0-427.44.1.vz9.80.6
------>
commit e44e7893e18a2505e60dca4edff3481971e75ef3
Author: Alexander Atanasov <alexander.atana...@virtuozzo.com>
Date: Fri Jan 24 17:35:37 2025 +0200
dm-ploop: fsync after all pios are sent
Currently there are two workers one to handle pios,
one to handle flush (via vfs_fsync). This workers are
created unbound which means they are run whenever there is a free
CPU. When ploop sends pios (via ploop_dispatch_pios) it checks
if there are data and if there are flush pios. If both are
present both workers are scheduled to run. Which results in
a lot of writes and sync in parallel - which is slow and incorrect.
Slow due to the underlaying fs trying to write and sync, instead of
cache writes and then sync them. And incorrect due to the fact
that REQ_FLUSH ploop handles must complete after all is send to disk
which when run in parallel is not guaranteed to happen.
To address this process flushes after all pending pios are processed
and submitted and then process any pending flushes.
https://virtuozzo.atlassian.net/browse/VSTOR-93454
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 | 52 +++++++++++++++++++++++++++++------------------
1 file changed, 32 insertions(+), 20 deletions(-)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 221e97ba84a9..010492e96f52 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -368,7 +368,7 @@ void ploop_dispatch_pios(struct ploop *ploop, struct pio
*pio,
if (is_data)
queue_work(ploop->wq, &ploop->worker);
- if (is_flush)
+ else if (is_flush)
queue_work(ploop->wq, &ploop->fsync_worker);
}
@@ -1786,6 +1786,30 @@ static void ploop_submit_metadata_writeback(struct ploop
*ploop)
}
}
+static void process_ploop_fsync_work(struct ploop *ploop)
+{
+ LIST_HEAD(flush_pios);
+ struct file *file;
+ struct pio *pio;
+ int ret;
+
+ spin_lock_irq(&ploop->deferred_lock);
+ list_splice_init(&ploop->pios[PLOOP_LIST_FLUSH], &flush_pios);
+ spin_unlock_irq(&ploop->deferred_lock);
+
+ file = ploop_top_delta(ploop)->file;
+ ret = vfs_fsync(file, 0);
+
+ while ((pio = ploop_pio_list_pop(&flush_pios)) != NULL) {
+ if (unlikely(ret)) {
+ pio->bi_status = errno_to_blk_status(ret);
+ if (static_branch_unlikely(&ploop_standby_check))
+ ploop_check_standby_mode(ploop, ret);
+ }
+ ploop_pio_endio(pio);
+ }
+}
+
void do_ploop_work(struct work_struct *ws)
{
struct ploop *ploop = container_of(ws, struct ploop, worker);
@@ -1794,6 +1818,7 @@ void do_ploop_work(struct work_struct *ws)
LIST_HEAD(discard_pios);
LIST_HEAD(cow_pios);
LIST_HEAD(resubmit_pios);
+ bool do_fsync = false;
unsigned int old_flags = current->flags;
current->flags |= PF_IO_THREAD|PF_LOCAL_THROTTLE|PF_MEMALLOC_NOIO;
@@ -1804,6 +1829,8 @@ void do_ploop_work(struct work_struct *ws)
list_splice_init(&ploop->pios[PLOOP_LIST_DISCARD], &discard_pios);
list_splice_init(&ploop->pios[PLOOP_LIST_COW], &cow_pios);
list_splice_init(&ploop->resubmit_pios, &resubmit_pios);
+ if (!list_empty(&ploop->pios[PLOOP_LIST_FLUSH]))
+ do_fsync = true;
spin_unlock_irq(&ploop->deferred_lock);
ploop_prepare_embedded_pios(ploop, &embedded_pios, &deferred_pios);
@@ -1816,31 +1843,16 @@ void do_ploop_work(struct work_struct *ws)
ploop_submit_metadata_writeback(ploop);
current->flags = old_flags;
+
+ if (do_fsync)
+ process_ploop_fsync_work(ploop);
}
void do_ploop_fsync_work(struct work_struct *ws)
{
struct ploop *ploop = container_of(ws, struct ploop, fsync_worker);
- LIST_HEAD(flush_pios);
- struct file *file;
- struct pio *pio;
- int ret;
- spin_lock_irq(&ploop->deferred_lock);
- list_splice_init(&ploop->pios[PLOOP_LIST_FLUSH], &flush_pios);
- spin_unlock_irq(&ploop->deferred_lock);
-
- file = ploop_top_delta(ploop)->file;
- ret = vfs_fsync(file, 0);
-
- while ((pio = ploop_pio_list_pop(&flush_pios)) != NULL) {
- if (unlikely(ret)) {
- pio->bi_status = errno_to_blk_status(ret);
- if (static_branch_unlikely(&ploop_standby_check))
- ploop_check_standby_mode(ploop, ret);
- }
- ploop_pio_endio(pio);
- }
+ process_ploop_fsync_work(ploop);
}
static void ploop_submit_embedded_pio(struct ploop *ploop, struct pio *pio)
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