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drbd: Allow drbd_epoch_entries to use multiple bios.
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This should allow for better performance if the lower level IO stack
of the peers differs in limits exposed either via the queue,
or via some merge_bvec_fn.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
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Lars Ellenberg authored and Philipp Reisner committed May 18, 2010
1 parent 708d740 commit 45bb912
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Showing 6 changed files with 480 additions and 324 deletions.
90 changes: 74 additions & 16 deletions drivers/block/drbd/drbd_int.h
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Original file line number Diff line number Diff line change
Expand Up @@ -740,18 +740,6 @@ enum epoch_event {
EV_CLEANUP = 32, /* used as flag */
};

struct drbd_epoch_entry {
struct drbd_work w;
struct drbd_conf *mdev;
struct bio *private_bio;
struct hlist_node colision;
sector_t sector;
unsigned int size;
unsigned int flags;
struct drbd_epoch *epoch;
u64 block_id;
};

struct drbd_wq_barrier {
struct drbd_work w;
struct completion done;
Expand All @@ -762,17 +750,49 @@ struct digest_info {
void *digest;
};

/* ee flag bits */
struct drbd_epoch_entry {
struct drbd_work w;
struct hlist_node colision;
struct drbd_epoch *epoch;
struct drbd_conf *mdev;
struct page *pages;
atomic_t pending_bios;
unsigned int size;
/* see comments on ee flag bits below */
unsigned long flags;
sector_t sector;
u64 block_id;
};

/* ee flag bits.
* While corresponding bios are in flight, the only modification will be
* set_bit WAS_ERROR, which has to be atomic.
* If no bios are in flight yet, or all have been completed,
* non-atomic modification to ee->flags is ok.
*/
enum {
__EE_CALL_AL_COMPLETE_IO,
__EE_CONFLICT_PENDING,
__EE_MAY_SET_IN_SYNC,

/* This epoch entry closes an epoch using a barrier.
* On sucessful completion, the epoch is released,
* and the P_BARRIER_ACK send. */
__EE_IS_BARRIER,

/* In case a barrier failed,
* we need to resubmit without the barrier flag. */
__EE_RESUBMITTED,

/* we may have several bios per epoch entry.
* if any of those fail, we set this flag atomically
* from the endio callback */
__EE_WAS_ERROR,
};
#define EE_CALL_AL_COMPLETE_IO (1<<__EE_CALL_AL_COMPLETE_IO)
#define EE_CONFLICT_PENDING (1<<__EE_CONFLICT_PENDING)
#define EE_MAY_SET_IN_SYNC (1<<__EE_MAY_SET_IN_SYNC)
#define EE_IS_BARRIER (1<<__EE_IS_BARRIER)
#define EE_RESUBMITTED (1<<__EE_RESUBMITTED)
#define EE_WAS_ERROR (1<<__EE_WAS_ERROR)

/* global flag bits */
enum {
Expand Down Expand Up @@ -1441,7 +1461,8 @@ static inline void ov_oos_print(struct drbd_conf *mdev)
}


extern void drbd_csum(struct drbd_conf *, struct crypto_hash *, struct bio *, void *);
extern void drbd_csum_bio(struct drbd_conf *, struct crypto_hash *, struct bio *, void *);
extern void drbd_csum_ee(struct drbd_conf *, struct crypto_hash *, struct drbd_epoch_entry *, void *);
/* worker callbacks */
extern int w_req_cancel_conflict(struct drbd_conf *, struct drbd_work *, int);
extern int w_read_retry_remote(struct drbd_conf *, struct drbd_work *, int);
Expand All @@ -1465,6 +1486,8 @@ extern int w_e_reissue(struct drbd_conf *, struct drbd_work *, int);
extern void resync_timer_fn(unsigned long data);

/* drbd_receiver.c */
extern int drbd_submit_ee(struct drbd_conf *mdev, struct drbd_epoch_entry *e,
const unsigned rw, const int fault_type);
extern int drbd_release_ee(struct drbd_conf *mdev, struct list_head *list);
extern struct drbd_epoch_entry *drbd_alloc_ee(struct drbd_conf *mdev,
u64 id,
Expand Down Expand Up @@ -1620,6 +1643,41 @@ void drbd_bcast_ee(struct drbd_conf *mdev,
* inline helper functions
*************************/

/* see also page_chain_add and friends in drbd_receiver.c */
static inline struct page *page_chain_next(struct page *page)
{
return (struct page *)page_private(page);
}
#define page_chain_for_each(page) \
for (; page && ({ prefetch(page_chain_next(page)); 1; }); \
page = page_chain_next(page))
#define page_chain_for_each_safe(page, n) \
for (; page && ({ n = page_chain_next(page); 1; }); page = n)

static inline int drbd_bio_has_active_page(struct bio *bio)
{
struct bio_vec *bvec;
int i;

__bio_for_each_segment(bvec, bio, i, 0) {
if (page_count(bvec->bv_page) > 1)
return 1;
}

return 0;
}

static inline int drbd_ee_has_active_page(struct drbd_epoch_entry *e)
{
struct page *page = e->pages;
page_chain_for_each(page) {
if (page_count(page) > 1)
return 1;
}
return 0;
}


static inline void drbd_state_lock(struct drbd_conf *mdev)
{
wait_event(mdev->misc_wait,
Expand Down
19 changes: 16 additions & 3 deletions drivers/block/drbd/drbd_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2354,6 +2354,19 @@ static int _drbd_send_zc_bio(struct drbd_conf *mdev, struct bio *bio)
return 1;
}

static int _drbd_send_zc_ee(struct drbd_conf *mdev, struct drbd_epoch_entry *e)
{
struct page *page = e->pages;
unsigned len = e->size;
page_chain_for_each(page) {
unsigned l = min_t(unsigned, len, PAGE_SIZE);
if (!_drbd_send_page(mdev, page, 0, l))
return 0;
len -= l;
}
return 1;
}

static void consider_delay_probes(struct drbd_conf *mdev)
{
if (mdev->state.conn != C_SYNC_SOURCE || mdev->agreed_pro_version < 93)
Expand Down Expand Up @@ -2430,7 +2443,7 @@ int drbd_send_dblock(struct drbd_conf *mdev, struct drbd_request *req)
drbd_send(mdev, mdev->data.socket, &p, sizeof(p), MSG_MORE));
if (ok && dgs) {
dgb = mdev->int_dig_out;
drbd_csum(mdev, mdev->integrity_w_tfm, req->master_bio, dgb);
drbd_csum_bio(mdev, mdev->integrity_w_tfm, req->master_bio, dgb);
ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, MSG_MORE);
}
if (ok) {
Expand Down Expand Up @@ -2483,11 +2496,11 @@ int drbd_send_block(struct drbd_conf *mdev, enum drbd_packets cmd,
sizeof(p), MSG_MORE);
if (ok && dgs) {
dgb = mdev->int_dig_out;
drbd_csum(mdev, mdev->integrity_w_tfm, e->private_bio, dgb);
drbd_csum_ee(mdev, mdev->integrity_w_tfm, e, dgb);
ok = drbd_send(mdev, mdev->data.socket, dgb, dgs, MSG_MORE);
}
if (ok)
ok = _drbd_send_zc_bio(mdev, e->private_bio);
ok = _drbd_send_zc_ee(mdev, e);

drbd_put_data_sock(mdev);

Expand Down
18 changes: 11 additions & 7 deletions drivers/block/drbd/drbd_nl.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2215,9 +2215,9 @@ void drbd_bcast_ee(struct drbd_conf *mdev,
{
struct cn_msg *cn_reply;
struct drbd_nl_cfg_reply *reply;
struct bio_vec *bvec;
unsigned short *tl;
int i;
struct page *page;
unsigned len;

if (!e)
return;
Expand Down Expand Up @@ -2255,11 +2255,15 @@ void drbd_bcast_ee(struct drbd_conf *mdev,
put_unaligned(T_ee_data, tl++);
put_unaligned(e->size, tl++);

__bio_for_each_segment(bvec, e->private_bio, i, 0) {
void *d = kmap(bvec->bv_page);
memcpy(tl, d + bvec->bv_offset, bvec->bv_len);
kunmap(bvec->bv_page);
tl=(unsigned short*)((char*)tl + bvec->bv_len);
len = e->size;
page = e->pages;
page_chain_for_each(page) {
void *d = kmap_atomic(page, KM_USER0);
unsigned l = min_t(unsigned, len, PAGE_SIZE);
memcpy(tl, d, l);
kunmap_atomic(d, KM_USER0);
tl = (unsigned short*)((char*)tl + l);
len -= l;
}
put_unaligned(TT_END, tl++); /* Close the tag list */

Expand Down
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