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Flush lbd on a timer in lbdcache instead of the main module

This commit is contained in:
Tom Marshall 2019-11-08 12:24:21 -08:00
parent 68956f70e8
commit bd51b7cb89
3 changed files with 108 additions and 112 deletions
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106
dm-compress/compress.c
View File

@ -57,10 +57,6 @@ struct compress
struct lbdcache* lc;
struct workqueue_struct* io_workq;
struct mutex lbd_lock;
void* __percpu lbd_percpu;
struct work_struct lbd_work;
};
static inline u64
@ -199,55 +195,6 @@ compress_write_header(struct compress* c)
return ret;
}
static void
compress_flush(struct work_struct* work)
{
struct compress* c = container_of(work, struct compress, lbd_work);
int cpu;
struct lbd** lbdp;
mutex_lock(&c->lbd_lock);
for (cpu = 0; cpu < num_online_cpus(); ++cpu) {
lbdp = per_cpu_ptr(c->lbd_percpu, cpu);
lbdcache_put(c->lc, *lbdp, &c->stats); /* XXX: check error */
*lbdp = NULL;
}
mutex_unlock(&c->lbd_lock);
}
static struct lbd*
compress_get_lbd(struct compress* c)
{
int cpu;
struct lbd** lbdp;
struct lbd* lbd;
mutex_lock(&c->lbd_lock);
cpu = get_cpu();
lbdp = per_cpu_ptr(c->lbd_percpu, cpu);
lbd = *lbdp;
*lbdp = NULL;
put_cpu();
mutex_unlock(&c->lbd_lock);
return lbd;
}
static void
compress_put_lbd(struct compress* c, struct lbd* lbd)
{
int cpu;
struct lbd** lbdp;
mutex_lock(&c->lbd_lock);
cpu = get_cpu();
lbdp = per_cpu_ptr(c->lbd_percpu, cpu);
lbdcache_put(c->lc, *lbdp, &c->stats); /* XXX: check error */
*lbdp = lbd;
put_cpu();
mutex_unlock(&c->lbd_lock);
}
static int
compress_read(struct compress *c, struct bio *bio)
{
@ -255,34 +202,22 @@ compress_read(struct compress *c, struct bio *bio)
struct bio_vec bv;
struct bvec_iter iter;
u32 lblk_per_sector = lblk_per_pblk(&c->params) * PBLK_PER_SECTOR;
u64 last_lblk = LBLK_NONE;
lbd = compress_get_lbd(c);
if (lbd) {
last_lblk = lbd_lblk(lbd);
}
bio_for_each_segment(bv, bio, iter) {
u64 lblk = iter.bi_sector / lblk_per_sector;
u32 lblk_off = (iter.bi_sector - lblk * lblk_per_sector) * SECTOR_SIZE;
unsigned long flags;
char* data;
if (lblk != last_lblk) {
struct lbd* newlbd = lbdcache_get(c->lc, lblk);
lbdcache_put(c->lc, lbd, &c->stats);
if (!newlbd) {
return -EIO;
}
lbd = newlbd;
last_lblk = lblk;
lbd = lbdcache_get(c->lc, lblk);
if (!lbd) {
return -EIO;
}
data = bvec_kmap_irq(&bv, &flags);
lbd_data_read(lbd, lblk_off, bv.bv_len, data);
bvec_kunmap_irq(data, &flags);
lbdcache_put(c->lc, lbd);
}
compress_put_lbd(c, lbd);
schedule_work(&c->lbd_work);
return 0;
}
@ -294,34 +229,22 @@ compress_write(struct compress *c, struct bio *bio)
struct bio_vec bv;
struct bvec_iter iter;
u32 lblk_per_sector = lblk_per_pblk(&c->params) * PBLK_PER_SECTOR;
u64 last_lblk = LBLK_NONE;
lbd = compress_get_lbd(c);
if (lbd) {
last_lblk = lbd_lblk(lbd);
}
bio_for_each_segment(bv, bio, iter) {
u64 lblk = iter.bi_sector / lblk_per_sector;
u32 lblk_off = (iter.bi_sector - lblk * lblk_per_sector) * SECTOR_SIZE;
unsigned long flags;
char* data;
if (lblk != last_lblk) {
struct lbd* newlbd = lbdcache_get(c->lc, lblk);
lbdcache_put(c->lc, lbd, &c->stats);
if (!newlbd) {
return -EIO;
}
lbd = newlbd;
last_lblk = lblk;
lbd = lbdcache_get(c->lc, lblk);
if (!lbd) {
return -EIO;
}
data = bvec_kmap_irq(&bv, &flags);
lbd_data_write(lbd, lblk_off, bv.bv_len, data);
bvec_kunmap_irq(data, &flags);
lbdcache_put(c->lc, lbd);
}
compress_put_lbd(c, lbd);
schedule_work(&c->lbd_work);
return 0;
}
@ -498,7 +421,7 @@ compress_ctr(struct dm_target *ti, unsigned int argc, char **argv)
ret = -ENOMEM;
goto err;
}
if (!lbdcache_ctr(c->lc, &c->params, cache_pages)) {
if (!lbdcache_ctr(c->lc, &c->params, &c->stats, cache_pages)) {
printk(KERN_ERR "Failed to init logical block cache\n");
ret = -ENOMEM;
goto err;
@ -511,10 +434,6 @@ compress_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto err;
}
mutex_init(&c->lbd_lock);
c->lbd_percpu = alloc_percpu(void*);
INIT_WORK(&c->lbd_work, compress_flush);
printk(KERN_INFO "%s: success\n", __func__);
return 0;
@ -530,7 +449,6 @@ compress_dtr(struct dm_target *ti)
{
int ret;
struct compress *c;
int cpu;
printk(KERN_INFO "%s: enter\n", __func__);
@ -542,12 +460,6 @@ compress_dtr(struct dm_target *ti)
printk(KERN_INFO "Warning: failed to write header\n");
}
}
cancel_work_sync(&c->lbd_work);
for (cpu = 0; cpu < num_online_cpus(); ++cpu) {
struct lbd** lbdp = per_cpu_ptr(c->lbd_percpu, cpu);
lbdcache_put(c->lc, *lbdp, &c->stats);
}
free_percpu(c->lbd_percpu);
lbdcache_dtr(c->lc);
kfree(c->lc);
if (c->io_workq) {

107
dm-compress/lbd.c
View File

@ -31,7 +31,9 @@
#include <linux/dm-compress.h>
struct lbd {
struct list_head list;
struct list_head lru_list;
struct list_head flush_list;
unsigned long flush_jiffies;
u64 lblk;
struct mutex reflock;
unsigned int ref;
@ -255,7 +257,9 @@ lbd_ctr(struct lbd* lbd,
u32 nr_pages = lblk_per_pblk(params);
memset(lbd, 0, sizeof(struct lbd));
INIT_LIST_HEAD(&lbd->list);
INIT_LIST_HEAD(&lbd->lru_list);
INIT_LIST_HEAD(&lbd->flush_list);
lbd->flush_jiffies = 0;
lbd->lblk = LBLK_NONE;
mutex_init(&lbd->reflock);
lbd->ref = 0;
@ -507,13 +511,18 @@ struct lbdcache
{
struct mutex lock;
struct cbd_params* params;
struct cbd_stats* stats;
void* percpu;
struct lbatviewcache* lvc;
struct list_head cache_head;
unsigned int cache_len;
struct lbd* cache;
struct delayed_work flush_dwork;
struct list_head flush_head;
};
static void lbdcache_flush(struct work_struct*);
size_t
lbdcache_size(void)
{
@ -594,7 +603,8 @@ lbdcache_free_compress_state(void* percpu, const struct cbd_params* params, int
bool
lbdcache_ctr(struct lbdcache* lc,
struct cbd_params* params, u32 cache_pages)
struct cbd_params* params, struct cbd_stats* stats,
u32 cache_pages)
{
int cpu;
struct lbd* cache;
@ -604,6 +614,7 @@ lbdcache_ctr(struct lbdcache* lc,
memset(lc, 0, sizeof(struct lbdcache));
mutex_init(&lc->lock);
lc->params = params;
lc->stats = stats;
lc->percpu = alloc_percpu(void*);
for (cpu = 0; cpu < num_online_cpus(); ++cpu) {
if (!lbdcache_alloc_compress_state(lc->percpu, params, cpu)) {
@ -636,8 +647,10 @@ lbdcache_ctr(struct lbdcache* lc,
if (!lbd_ctr(&cache[n], params, lc->lvc, lc->percpu)) {
return false;
}
list_add_tail(&cache[n].list, &lc->cache_head);
list_add_tail(&cache[n].lru_list, &lc->cache_head);
}
INIT_DELAYED_WORK(&lc->flush_dwork, lbdcache_flush);
INIT_LIST_HEAD(&lc->flush_head);
return true;
}
@ -645,10 +658,19 @@ lbdcache_ctr(struct lbdcache* lc,
void
lbdcache_dtr(struct lbdcache* lc)
{
int ret;
unsigned int n;
struct lbd* lbd;
int cpu;
cancel_delayed_work_sync(&lc->flush_dwork);
flush_delayed_work(&lc->flush_dwork);
list_for_each_entry(lbd, &lc->flush_head, flush_list) {
ret = lbd_flush(lbd, lc->stats);
if (ret) {
printk(KERN_ERR "%s: lbd_flush failed\n", __func__);
}
}
for (n = 0; n < lc->cache_len; ++n) {
lbd = &lc->cache[n];
if (!lbd) {
@ -674,38 +696,92 @@ lbdcache_dtr(struct lbdcache* lc)
lc->params = NULL;
}
static void
lbdcache_flush(struct work_struct* work)
{
struct lbdcache* lc = container_of(work, struct lbdcache, flush_dwork.work);
unsigned long now = jiffies;
int ret;
struct lbd* lbd;
mutex_lock(&lc->lock);
while (!list_empty(&lc->flush_head)) {
lbd = list_first_entry(&lc->flush_head, struct lbd, flush_list);
mutex_lock(&lbd->reflock);
BUG_ON(lbd->ref != 1);
if (lbd->flush_jiffies > now) {
mutex_unlock(&lbd->reflock);
break;
}
list_del_init(&lbd->flush_list);
lbd->ref = 0;
ret = lbd_flush(lbd, lc->stats);
if (ret) {
printk(KERN_ERR "%s: lbd_flush failed\n", __func__);
}
mutex_unlock(&lbd->reflock);
}
if (!list_empty(&lc->flush_head)) {
schedule_delayed_work(&lc->flush_dwork, COMPRESS_FLUSH_DELAY);
}
mutex_unlock(&lc->lock);
}
struct lbd*
lbdcache_get(struct lbdcache* lc, u64 lblk)
{
struct lbd* lbd;
mutex_lock(&lc->lock);
list_for_each_entry(lbd, &lc->cache_head, list) {
list_for_each_entry(lbd, &lc->cache_head, lru_list) {
mutex_lock(&lbd->reflock);
if (lbd->lblk == lblk) {
list_move(&lbd->list, &lc->cache_head);
list_move(&lbd->lru_list, &lc->cache_head);
if (lbd->ref == 0) {
goto found;
}
if (lbd->ref == 1 && !list_empty(&lc->flush_head)) {
struct lbd* entry;
list_for_each_entry(entry, &lc->flush_head, flush_list) {
if (entry == lbd) {
list_del_init(&lbd->flush_list);
lbd->ref = 0;
break;
}
}
}
mutex_unlock(&lc->lock);
++lbd->ref;
mutex_unlock(&lbd->reflock);
return lbd;
}
if (lbd->lblk == LBLK_NONE) {
list_move(&lbd->list, &lc->cache_head);
list_move(&lbd->lru_list, &lc->cache_head);
goto found;
}
mutex_unlock(&lbd->reflock);
}
list_for_each_entry_reverse(lbd, &lc->cache_head, list) {
list_for_each_entry_reverse(lbd, &lc->cache_head, lru_list) {
mutex_lock(&lbd->reflock);
if (lbd->ref == 0 && !lbd_error(lbd)) {
list_move(&lbd->list, &lc->cache_head);
list_move(&lbd->lru_list, &lc->cache_head);
goto found;
}
mutex_unlock(&lbd->reflock);
}
if (!list_empty(&lc->flush_head)) {
int ret;
lbd = list_first_entry(&lc->flush_head, struct lbd, flush_list);
mutex_lock(&lbd->reflock);
BUG_ON(lbd->ref != 1);
list_del_init(&lbd->flush_list);
lbd->ref = 0;
ret = lbd_flush(lbd, lc->stats);
if (ret) {
printk(KERN_ERR "%s: lbd_flush failed\n", __func__);
}
goto found;
}
printk(KERN_ERR "%s: failed to find free entry\n", __func__);
mutex_unlock(&lc->lock);
return NULL;
@ -723,21 +799,26 @@ found:
}
int
lbdcache_put(struct lbdcache* lc, struct lbd* lbd, struct cbd_stats* stats)
lbdcache_put(struct lbdcache* lc, struct lbd* lbd)
{
int ret = 0;
if (!lbd) {
return 0;
}
mutex_lock(&lc->lock);
mutex_lock(&lbd->reflock);
if (--lbd->ref == 0) {
ret = lbd_flush(lbd, stats);
if (ret) {
printk(KERN_ERR "%s: lbd_flush failed\n", __func__);
lbd->flush_jiffies = jiffies + COMPRESS_FLUSH_DELAY;
lbd->ref = 1;
list_add_tail(&lbd->flush_list, &lc->flush_head);
/* This is racy, but it does not matter. */
if (!delayed_work_pending(&lc->flush_dwork)) {
schedule_delayed_work(&lc->flush_dwork, COMPRESS_FLUSH_DELAY);
}
}
mutex_unlock(&lbd->reflock);
mutex_unlock(&lc->lock);
return ret;
}

7
include/linux/dm-compress.h
View File

@ -506,6 +506,8 @@ lba_put(const struct cbd_params* params,
#define COMPRESS_HAVE_ZLIB 1
#endif
#define COMPRESS_FLUSH_DELAY (HZ / 10)
typedef void (*pblk_endio_t)(struct bio*);
/* Single page allocator */
@ -578,11 +580,12 @@ void lbd_data_write(struct lbd* lbd, u32 off, u32 len, const u8* buf);
struct lbdcache;
size_t lbdcache_size(void);
bool lbdcache_ctr(struct lbdcache* lc,
struct cbd_params* params, u32 cache_pages);
struct cbd_params* params, struct cbd_stats* stats,
u32 cache_pages);
void lbdcache_dtr(struct lbdcache* lc);
struct lbd*
lbdcache_get(struct lbdcache* lc, u64 lblk);
int lbdcache_put(struct lbdcache* lc, struct lbd* lbd, struct cbd_stats* stats);
int lbdcache_put(struct lbdcache* lc, struct lbd* lbd);
#endif