[Devel] [PATCH RHEL9 COMMIT] dm-ploop: speed up ploop_prepare_bat_update()
Konstantin Khorenko
khorenko at virtuozzo.com
Mon Jan 27 16:12:39 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 ac9fa0f4e6475ed064026c58d3a492218ff65acb
Author: Andrey Zhadchenko <andrey.zhadchenko at virtuozzo.com>
Date: Fri Jan 24 17:35:53 2025 +0200
dm-ploop: speed up ploop_prepare_bat_update()
Drop ploop_cluster_is_in_top_delta(), because
- it internally searches md on every call
- it takes read lock every time
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 | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 90290221341b..953eecb9555c 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -900,13 +900,14 @@ static void ploop_bat_write_complete(struct pio *pio, void *piwb_ptr,
static int ploop_prepare_bat_update(struct ploop *ploop, struct md_page *md,
enum piwb_type type)
{
- u32 i, off, last, *bat_entries;
+ u32 i, off, last, *bat_entries, clu;
struct ploop_index_wb *piwb;
bool is_last_page = true;
u32 page_id = md->id;
struct page *page;
struct pio *pio;
map_index_t *to;
+ u8 level;
piwb = kmalloc(sizeof(*piwb), GFP_NOIO);
if (!piwb)
@@ -928,6 +929,8 @@ static int ploop_prepare_bat_update(struct ploop *ploop, struct md_page *md,
piwb->page_id = page_id;
to = kmap_local_page(page);
+
+ read_lock_irq(&md->lock);
memcpy((void *)to, bat_entries, PAGE_SIZE);
/* Absolute number of first index in page (negative for page#0) */
@@ -946,10 +949,14 @@ static int ploop_prepare_bat_update(struct ploop *ploop, struct md_page *md,
/* Copy BAT (BAT goes right after hdr, see .ctr) */
for (; i < last; i++) {
- if (ploop_cluster_is_in_top_delta(ploop, i + off))
- continue;
- to[i] = 0;
+ level = md->bat_levels[i];
+ clu = READ_ONCE(bat_entries[i]);
+
+ if (clu == BAT_ENTRY_NONE || level < ploop_top_level(ploop))
+ to[i] = 0;
}
+ read_unlock_irq(&md->lock);
+
if (is_last_page) {
/* Fill tail of page with 0 */
for (i = last; i < PAGE_SIZE / sizeof(map_index_t); i++)
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