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drbd: Remove the open-coded page pool

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If the network stack keeps a reference for too long, DRBD keeps
references on a higher number of pages as a consequence.

Fix all that by no longer relying on page reference counts dropping to
an expected value. Instead, DRBD gives up its reference and lets the
system handle everything else. While at it, remove the open-coded
custom page pool mechanism and use the page_pool included in the
kernel.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Tested-by: Eric Hagberg <ehagberg@janestreet.com>
Link: https://lore.kernel.org/r/20250605103852.23029-1-christoph.boehmwalder@linbit.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Philipp Reisner
2025-06-05 12:38:52 +02:00
committed by Jens Axboe
parent 8f5ae30d69
commit d5dd409812
4 changed files with 70 additions and 346 deletions
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59
drivers/block/drbd/drbd_main.c
View File

@@ -114,20 +114,10 @@ struct kmem_cache *drbd_al_ext_cache; /* activity log extents */
mempool_t drbd_request_mempool;
mempool_t drbd_ee_mempool;
mempool_t drbd_md_io_page_pool;
mempool_t drbd_buffer_page_pool;
struct bio_set drbd_md_io_bio_set;
struct bio_set drbd_io_bio_set;
/* I do not use a standard mempool, because:
1) I want to hand out the pre-allocated objects first.
2) I want to be able to interrupt sleeping allocation with a signal.
Note: This is a single linked list, the next pointer is the private
member of struct page.
*/
struct page *drbd_pp_pool;
DEFINE_SPINLOCK(drbd_pp_lock);
int drbd_pp_vacant;
wait_queue_head_t drbd_pp_wait;
DEFINE_RATELIMIT_STATE(drbd_ratelimit_state, 5 * HZ, 5);
static const struct block_device_operations drbd_ops = {
@@ -1611,6 +1601,7 @@ static int _drbd_send_zc_bio(struct drbd_peer_device *peer_device, struct bio *b
static int _drbd_send_zc_ee(struct drbd_peer_device *peer_device,
struct drbd_peer_request *peer_req)
{
bool use_sendpage = !(peer_req->flags & EE_RELEASE_TO_MEMPOOL);
struct page *page = peer_req->pages;
unsigned len = peer_req->i.size;
int err;
@@ -1619,8 +1610,13 @@ static int _drbd_send_zc_ee(struct drbd_peer_device *peer_device,
page_chain_for_each(page) {
unsigned l = min_t(unsigned, len, PAGE_SIZE);
err = _drbd_send_page(peer_device, page, 0, l,
page_chain_next(page) ? MSG_MORE : 0);
if (likely(use_sendpage))
err = _drbd_send_page(peer_device, page, 0, l,
page_chain_next(page) ? MSG_MORE : 0);
else
err = _drbd_no_send_page(peer_device, page, 0, l,
page_chain_next(page) ? MSG_MORE : 0);
if (err)
return err;
len -= l;
@@ -1962,7 +1958,6 @@ void drbd_init_set_defaults(struct drbd_device *device)
INIT_LIST_HEAD(&device->sync_ee);
INIT_LIST_HEAD(&device->done_ee);
INIT_LIST_HEAD(&device->read_ee);
INIT_LIST_HEAD(&device->net_ee);
INIT_LIST_HEAD(&device->resync_reads);
INIT_LIST_HEAD(&device->resync_work.list);
INIT_LIST_HEAD(&device->unplug_work.list);
@@ -2043,7 +2038,6 @@ void drbd_device_cleanup(struct drbd_device *device)
D_ASSERT(device, list_empty(&device->sync_ee));
D_ASSERT(device, list_empty(&device->done_ee));
D_ASSERT(device, list_empty(&device->read_ee));
D_ASSERT(device, list_empty(&device->net_ee));
D_ASSERT(device, list_empty(&device->resync_reads));
D_ASSERT(device, list_empty(&first_peer_device(device)->connection->sender_work.q));
D_ASSERT(device, list_empty(&device->resync_work.list));
@@ -2055,19 +2049,11 @@ void drbd_device_cleanup(struct drbd_device *device)
static void drbd_destroy_mempools(void)
{
struct page *page;
while (drbd_pp_pool) {
page = drbd_pp_pool;
drbd_pp_pool = (struct page *)page_private(page);
__free_page(page);
drbd_pp_vacant--;
}
/* D_ASSERT(device, atomic_read(&drbd_pp_vacant)==0); */
bioset_exit(&drbd_io_bio_set);
bioset_exit(&drbd_md_io_bio_set);
mempool_exit(&drbd_buffer_page_pool);
mempool_exit(&drbd_md_io_page_pool);
mempool_exit(&drbd_ee_mempool);
mempool_exit(&drbd_request_mempool);
@@ -2086,9 +2072,8 @@ static void drbd_destroy_mempools(void)
static int drbd_create_mempools(void)
{
struct page *page;
const int number = (DRBD_MAX_BIO_SIZE/PAGE_SIZE) * drbd_minor_count;
int i, ret;
int ret;
/* caches */
drbd_request_cache = kmem_cache_create(
@@ -2125,6 +2110,10 @@ static int drbd_create_mempools(void)
if (ret)
goto Enomem;
ret = mempool_init_page_pool(&drbd_buffer_page_pool, number, 0);
if (ret)
goto Enomem;
ret = mempool_init_slab_pool(&drbd_request_mempool, number,
drbd_request_cache);
if (ret)
@@ -2134,15 +2123,6 @@ static int drbd_create_mempools(void)
if (ret)
goto Enomem;
for (i = 0; i < number; i++) {
page = alloc_page(GFP_HIGHUSER);
if (!page)
goto Enomem;
set_page_private(page, (unsigned long)drbd_pp_pool);
drbd_pp_pool = page;
}
drbd_pp_vacant = number;
return 0;
Enomem:
@@ -2169,10 +2149,6 @@ static void drbd_release_all_peer_reqs(struct drbd_device *device)
rr = drbd_free_peer_reqs(device, &device->done_ee);
if (rr)
drbd_err(device, "%d EEs in done list found!\n", rr);
rr = drbd_free_peer_reqs(device, &device->net_ee);
if (rr)
drbd_err(device, "%d EEs in net list found!\n", rr);
}
/* caution. no locking. */
@@ -2863,11 +2839,6 @@ static int __init drbd_init(void)
return err;
}
/*
* allocate all necessary structs
*/
init_waitqueue_head(&drbd_pp_wait);
drbd_proc = NULL; /* play safe for drbd_cleanup */
idr_init(&drbd_devices);