[Devel] [PATCH RHEL9 COMMIT] dm-ploop: move md status to use proper bitops
Konstantin Khorenko
khorenko at virtuozzo.com
Mon Jan 27 16:12:33 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 e820dda760ec423cbc615eff5856c2f33fc949e2
Author: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
Date: Fri Jan 24 17:35:38 2025 +0200
dm-ploop: move md status to use proper bitops
Fix direct bitops to use set_bit/clear_bit which
are atomic - this is required since there are
some places in code that do not use locking when
operating on that bits. this is also a preparation
to relax locking.
https://virtuozzo.atlassian.net/browse/VSTOR-91820
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-cmd.c | 2 +-
drivers/md/dm-ploop-map.c | 32 +++++++++++++++-----------------
drivers/md/dm-ploop.h | 2 +-
3 files changed, 17 insertions(+), 19 deletions(-)
diff --git a/drivers/md/dm-ploop-cmd.c b/drivers/md/dm-ploop-cmd.c
index 25ca9db4eeb8..ce6204c09e92 100644
--- a/drivers/md/dm-ploop-cmd.c
+++ b/drivers/md/dm-ploop-cmd.c
@@ -274,7 +274,7 @@ static int ploop_write_zero_cluster_sync(struct ploop *ploop,
static void ploop_make_md_wb(struct ploop *ploop, struct md_page *md)
{
write_lock_irq(&ploop->bat_rwlock);
- md->status |= MD_WRITEBACK;
+ set_bit(MD_WRITEBACK, &md->status);
write_unlock_irq(&ploop->bat_rwlock);
}
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index 010492e96f52..fc07d24c34a0 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -383,7 +383,7 @@ static bool ploop_delay_if_md_busy(struct ploop *ploop, struct md_page *md,
write_lock_irqsave(&ploop->bat_rwlock, flags);
piwb = md->piwb;
- if (piwb && (piwb->type != type || (md->status & MD_WRITEBACK))) {
+ if (piwb && (piwb->type != type || test_bit(MD_WRITEBACK, &md->status))) {
list_add_tail(&pio->list, &md->wait_list);
busy = true;
}
@@ -550,9 +550,8 @@ static bool ploop_md_make_dirty(struct ploop *ploop, struct md_page *md)
bool new = false;
write_lock_irqsave(&ploop->bat_rwlock, flags);
- WARN_ON_ONCE((md->status & MD_WRITEBACK));
- if (!(md->status & MD_DIRTY)) {
- md->status |= MD_DIRTY;
+ WARN_ON_ONCE(test_bit(MD_WRITEBACK, &md->status));
+ if (!test_and_set_bit(MD_DIRTY, &md->status)) {
list_add_tail(&md->wb_link, &ploop->wb_batch_list);
new = true;
}
@@ -800,8 +799,8 @@ static void ploop_advance_local_after_bat_wb(struct ploop *ploop,
}
}
- WARN_ON_ONCE(!(md->status & MD_WRITEBACK));
- md->status &= ~MD_WRITEBACK;
+ WARN_ON_ONCE(!test_bit(MD_WRITEBACK, &md->status));
+ clear_bit(MD_WRITEBACK, &md->status);
md->piwb = NULL;
list_splice_tail_init(&md->wait_list, &list);
write_unlock_irqrestore(&ploop->bat_rwlock, flags);
@@ -1377,8 +1376,8 @@ static void ploop_submit_cow_index_wb(struct ploop_cow *cow)
if (ploop_delay_if_md_busy(ploop, md, PIWB_TYPE_ALLOC, cow->aux_pio))
goto out;
- if (!(md->status & MD_DIRTY)) {
- /* Unlocked, since MD_DIRTY is set and cleared from this work */
+ if (!test_bit(MD_DIRTY, &md->status)) {
+ /* MD_DIRTY is set and cleared from this work */
if (ploop_prepare_bat_update(ploop, md, PIWB_TYPE_ALLOC) < 0)
goto err_resource;
ploop_md_make_dirty(ploop, md);
@@ -1465,7 +1464,7 @@ static bool ploop_locate_new_cluster_and_attach_pio(struct ploop *ploop,
if (ploop_delay_if_md_busy(ploop, md, PIWB_TYPE_ALLOC, pio))
goto out;
- if (!(md->status & MD_DIRTY)) {
+ if (!test_bit(MD_DIRTY, &md->status)) {
/* Unlocked since MD_DIRTY is set and cleared from this work */
page_id = ploop_bat_clu_to_page_nr(clu);
if (ploop_prepare_bat_update(ploop, md, PIWB_TYPE_ALLOC) < 0) {
@@ -1708,7 +1707,7 @@ static void ploop_process_one_discard_pio(struct ploop *ploop, struct pio *pio)
if (ploop_delay_if_md_busy(ploop, md, PIWB_TYPE_DISCARD, pio))
goto out;
- if (!(md->status & MD_DIRTY)) {
+ if (!test_bit(MD_DIRTY, &md->status)) {
/* Unlocked since MD_DIRTY is set and cleared from this work */
if (ploop_prepare_bat_update(ploop, md, PIWB_TYPE_DISCARD) < 0) {
pio->bi_status = BLK_STS_RESOURCE;
@@ -1765,7 +1764,6 @@ static void ploop_process_resubmit_pios(struct ploop *ploop,
static void ploop_submit_metadata_writeback(struct ploop *ploop)
{
struct md_page *md;
-
while (1) {
write_lock_irq(&ploop->bat_rwlock);
md = list_first_entry_or_null(&ploop->wb_batch_list,
@@ -1776,10 +1774,10 @@ static void ploop_submit_metadata_writeback(struct ploop *ploop)
}
list_del_init(&md->wb_link);
/* L1L2 mustn't be redirtyed, when wb in-flight! */
- WARN_ON_ONCE(!(md->status & MD_DIRTY) ||
- (md->status & MD_WRITEBACK));
- md->status |= MD_WRITEBACK;
- md->status &= ~MD_DIRTY;
+ WARN_ON_ONCE(!test_bit(MD_DIRTY, &md->status));
+ WARN_ON_ONCE(test_bit(MD_WRITEBACK, &md->status));
+ set_bit(MD_WRITEBACK, &md->status);
+ clear_bit(MD_DIRTY, &md->status);
write_unlock_irq(&ploop->bat_rwlock);
ploop_index_wb_submit(ploop, md->piwb);
@@ -1957,8 +1955,8 @@ int ploop_prepare_reloc_index_wb(struct ploop *ploop,
type = PIWB_TYPE_RELOC;
err = -EIO;
- if ((md->status & (MD_DIRTY|MD_WRITEBACK))) {
- PL_ERR("Unexpected md status: %x", md->status);
+ if (test_bit(MD_DIRTY, &md->status) || test_bit(MD_WRITEBACK, &md->status)) {
+ PL_ERR("Unexpected md status: %lx", md->status);
goto out_error;
}
err = ploop_prepare_bat_update(ploop, md, type);
diff --git a/drivers/md/dm-ploop.h b/drivers/md/dm-ploop.h
index b42baccf9a00..75329adafb56 100644
--- a/drivers/md/dm-ploop.h
+++ b/drivers/md/dm-ploop.h
@@ -116,7 +116,7 @@ struct md_page {
u32 id; /* Number of this page starting from hdr */
#define MD_DIRTY (1U << 1) /* Page contains changes and wants writeback */
#define MD_WRITEBACK (1U << 2) /* Writeback was submitted */
- unsigned int status;
+ unsigned long status;
struct page *page;
void *kmpage;
u8 *bat_levels;
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