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drbd: Remove the open-coded page pool #9

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3d460ec
adding ci files
kawasaki Jun 9, 2025
5c5e419
drbd: Remove the open-coded page pool
Philipp-Reisner Jun 5, 2025
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28 changes: 28 additions & 0 deletions .github/workflows/kernel_build.yml
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Original file line number Diff line number Diff line change
@@ -0,0 +1,28 @@
name: blktests-ci

on:
pull_request:

jobs:
build-kernel:
runs-on: ubuntu-latest
steps:
- name: Configure git
run: |
git config --global --add safe.directory '*'
- name: Checkout git
run: |
sudo apt-get install -y libelf-dev
mkdir -p linux
cd linux
git init
git remote add origin https://github.com/${{ github.repository }}
git fetch origin --depth=5 ${{ github.event.pull_request.head.sha }}
git reset --hard ${{ github.event.pull_request.head.sha }}
git log -1
- name: Build kernel
run: |
cd linux
make defconfig
make -j 8

39 changes: 6 additions & 33 deletions drivers/block/drbd/drbd_int.h
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Original file line number Diff line number Diff line change
Expand Up @@ -380,6 +380,9 @@ enum {
/* this is/was a write request */
__EE_WRITE,

/* hand back using mempool_free(e, drbd_buffer_page_pool) */
__EE_RELEASE_TO_MEMPOOL,

/* this is/was a write same request */
__EE_WRITE_SAME,

Expand All @@ -402,6 +405,7 @@ enum {
#define EE_IN_INTERVAL_TREE (1<<__EE_IN_INTERVAL_TREE)
#define EE_SUBMITTED (1<<__EE_SUBMITTED)
#define EE_WRITE (1<<__EE_WRITE)
#define EE_RELEASE_TO_MEMPOOL (1<<__EE_RELEASE_TO_MEMPOOL)
#define EE_WRITE_SAME (1<<__EE_WRITE_SAME)
#define EE_APPLICATION (1<<__EE_APPLICATION)
#define EE_RS_THIN_REQ (1<<__EE_RS_THIN_REQ)
Expand Down Expand Up @@ -858,7 +862,6 @@ struct drbd_device {
struct list_head sync_ee; /* IO in progress (P_RS_DATA_REPLY gets written to disk) */
struct list_head done_ee; /* need to send P_WRITE_ACK */
struct list_head read_ee; /* [RS]P_DATA_REQUEST being read */
struct list_head net_ee; /* zero-copy network send in progress */

struct list_head resync_reads;
atomic_t pp_in_use; /* allocated from page pool */
Expand Down Expand Up @@ -1329,31 +1332,14 @@ extern struct kmem_cache *drbd_al_ext_cache; /* activity log extents */
extern mempool_t drbd_request_mempool;
extern mempool_t drbd_ee_mempool;

/* drbd's page pool, used to buffer data received from the peer,
* or data requested by the peer.
*
* This does not have an emergency reserve.
*
* When allocating from this pool, it first takes pages from the pool.
* Only if the pool is depleted will try to allocate from the system.
*
* The assumption is that pages taken from this pool will be processed,
* and given back, "quickly", and then can be recycled, so we can avoid
* frequent calls to alloc_page(), and still will be able to make progress even
* under memory pressure.
*/
extern struct page *drbd_pp_pool;
extern spinlock_t drbd_pp_lock;
extern int drbd_pp_vacant;
extern wait_queue_head_t drbd_pp_wait;

/* We also need a standard (emergency-reserve backed) page pool
* for meta data IO (activity log, bitmap).
* We can keep it global, as long as it is used as "N pages at a time".
* 128 should be plenty, currently we probably can get away with as few as 1.
*/
#define DRBD_MIN_POOL_PAGES 128
extern mempool_t drbd_md_io_page_pool;
extern mempool_t drbd_buffer_page_pool;

/* We also need to make sure we get a bio
* when we need it for housekeeping purposes */
Expand Down Expand Up @@ -1488,10 +1474,7 @@ extern struct drbd_peer_request *drbd_alloc_peer_req(struct drbd_peer_device *,
sector_t, unsigned int,
unsigned int,
gfp_t) __must_hold(local);
extern void __drbd_free_peer_req(struct drbd_device *, struct drbd_peer_request *,
int);
#define drbd_free_peer_req(m,e) __drbd_free_peer_req(m, e, 0)
#define drbd_free_net_peer_req(m,e) __drbd_free_peer_req(m, e, 1)
extern void drbd_free_peer_req(struct drbd_device *device, struct drbd_peer_request *req);
extern struct page *drbd_alloc_pages(struct drbd_peer_device *, unsigned int, bool);
extern void _drbd_clear_done_ee(struct drbd_device *device, struct list_head *to_be_freed);
extern int drbd_connected(struct drbd_peer_device *);
Expand Down Expand Up @@ -1610,16 +1593,6 @@ static inline struct page *page_chain_next(struct page *page)
for (; page && ({ n = page_chain_next(page); 1; }); page = n)


static inline int drbd_peer_req_has_active_page(struct drbd_peer_request *peer_req)
{
struct page *page = peer_req->pages;
page_chain_for_each(page) {
if (page_count(page) > 1)
return 1;
}
return 0;
}

static inline union drbd_state drbd_read_state(struct drbd_device *device)
{
struct drbd_resource *resource = device->resource;
Expand Down
59 changes: 15 additions & 44 deletions drivers/block/drbd/drbd_main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -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 = {
Expand Down Expand Up @@ -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;
Expand All @@ -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;
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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));
Expand All @@ -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);
Expand All @@ -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(
Expand Down Expand Up @@ -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)
Expand All @@ -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:
Expand All @@ -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. */
Expand Down Expand Up @@ -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);

Expand Down
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