[Devel] [PATCH RHEL9 COMMIT] dm-ploop: use GFP_ATOMIC instead of GFP_NOIO
Konstantin Khorenko
khorenko at virtuozzo.com
Mon Jan 27 16:12:55 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 99e18f6fee415ac23a9193d001bcc80fd520da16
Author: Alexander Atanasov <alexander.atanasov at virtuozzo.com>
Date: Fri Jan 24 17:36:35 2025 +0200
dm-ploop: use GFP_ATOMIC instead of GFP_NOIO
GFP_NOIO can sleep so we can not use it while we
are called from block layer and device mapper in
interrupt context. It is also invalid under rcu_nesting
which happens too.
(traces in the issue)
https://virtuozzo.atlassian.net/browse/VSTOR-98291
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 | 4 ++--
drivers/md/dm-ploop-map.c | 14 +++++++-------
2 files changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/md/dm-ploop-cmd.c b/drivers/md/dm-ploop-cmd.c
index 011d37f8fe3e..e032af52b64e 100644
--- a/drivers/md/dm-ploop-cmd.c
+++ b/drivers/md/dm-ploop-cmd.c
@@ -489,13 +489,13 @@ struct pio *ploop_alloc_pio_with_pages(struct ploop *ploop)
u32 size;
size = sizeof(*pio) + sizeof(*pio->bi_io_vec) * nr_pages;
- pio = kmalloc(size, GFP_NOIO);
+ pio = kmalloc(size, GFP_ATOMIC);
if (!pio)
return NULL;
pio->bi_io_vec = (void *)(pio + 1);
for (i = 0; i < nr_pages; i++) {
- pio->bi_io_vec[i].bv_page = alloc_page(GFP_NOIO);
+ pio->bi_io_vec[i].bv_page = alloc_page(GFP_ATOMIC);
if (!pio->bi_io_vec[i].bv_page)
goto err;
pio->bi_io_vec[i].bv_offset = 0;
diff --git a/drivers/md/dm-ploop-map.c b/drivers/md/dm-ploop-map.c
index ef0a7e10d1cc..a47341f40627 100644
--- a/drivers/md/dm-ploop-map.c
+++ b/drivers/md/dm-ploop-map.c
@@ -292,7 +292,7 @@ static struct pio *ploop_split_and_chain_pio(struct ploop *ploop,
{
struct pio *split;
- split = ploop_alloc_pio(ploop, GFP_NOIO);
+ split = ploop_alloc_pio(ploop, GFP_ATOMIC);
if (!split)
return NULL;
@@ -1017,13 +1017,13 @@ static int ploop_prepare_bat_update(struct ploop *ploop, struct md_page *md,
lockdep_assert_held(&ploop->bat_lock);
- piwb = kmalloc(sizeof(*piwb), GFP_NOIO);
+ piwb = kmalloc(sizeof(*piwb), GFP_ATOMIC);
if (!piwb)
return -ENOMEM;
ploop_index_wb_init(piwb, ploop);
- piwb->bat_page = page = alloc_page(GFP_NOIO);
- piwb->pio = pio = ploop_alloc_pio(ploop, GFP_NOIO);
+ piwb->bat_page = page = alloc_page(GFP_ATOMIC);
+ piwb->pio = pio = ploop_alloc_pio(ploop, GFP_ATOMIC);
if (!page || !pio)
goto err;
ploop_init_pio(ploop, REQ_OP_WRITE, pio);
@@ -1558,7 +1558,7 @@ static int ploop_submit_cluster_cow(struct ploop *ploop, unsigned int level,
/* Prepare new delta read */
aux_pio = ploop_alloc_pio_with_pages(ploop);
- cow = kmem_cache_alloc(cow_cache, GFP_NOIO);
+ cow = kmem_cache_alloc(cow_cache, GFP_ATOMIC);
if (!aux_pio || !cow)
goto err;
ploop_init_pio(ploop, REQ_OP_READ, aux_pio);
@@ -1904,7 +1904,7 @@ static struct bio_vec *ploop_create_bvec_from_rq(struct request *rq)
nr_bvec++;
bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec),
- GFP_NOIO);
+ GFP_ATOMIC);
if (!bvec)
goto out;
@@ -2417,7 +2417,7 @@ static int ploop_prepare_flush(struct ploop *ploop, struct pio *pio)
unsigned long flags;
if (pio->bi_op & REQ_PREFLUSH && (pio->bi_op & REQ_OP_MASK) != REQ_OP_FLUSH) {
- flush_pio = ploop_alloc_pio(ploop, GFP_NOIO);
+ flush_pio = ploop_alloc_pio(ploop, GFP_ATOMIC);
if (!flush_pio) {
pio->bi_status = BLK_STS_RESOURCE;
ploop_pio_endio(pio);
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