}
#ifdef CONFIG_ZRAM_WRITEBACK
+struct zram_wb_ctl {
+ /* idle list is accessed only by the writeback task, no concurency */
+ struct list_head idle_reqs;
+ /* done list is accessed concurrently, protect by done_lock */
+ struct list_head done_reqs;
+ wait_queue_head_t done_wait;
+ spinlock_t done_lock;
+ atomic_t num_inflight;
+};
+
+struct zram_wb_req {
+ unsigned long blk_idx;
+ struct page *page;
+ struct zram_pp_slot *pps;
+ struct bio_vec bio_vec;
+ struct bio bio;
+
+ struct list_head entry;
+};
+
static ssize_t writeback_limit_enable_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
submit_bio(bio);
}
-static int zram_writeback_slots(struct zram *zram, struct zram_pp_ctl *ctl)
+static void release_wb_req(struct zram_wb_req *req)
{
- unsigned long blk_idx = 0;
- struct page *page = NULL;
- struct zram_pp_slot *pps;
- struct bio_vec bio_vec;
- struct bio bio;
+ __free_page(req->page);
+ kfree(req);
+}
+
+static void release_wb_ctl(struct zram_wb_ctl *wb_ctl)
+{
+ if (!wb_ctl)
+ return;
+
+ /* We should never have inflight requests at this point */
+ WARN_ON(atomic_read(&wb_ctl->num_inflight));
+ WARN_ON(!list_empty(&wb_ctl->done_reqs));
+
+ while (!list_empty(&wb_ctl->idle_reqs)) {
+ struct zram_wb_req *req;
+
+ req = list_first_entry(&wb_ctl->idle_reqs,
+ struct zram_wb_req, entry);
+ list_del(&req->entry);
+ release_wb_req(req);
+ }
+
+ kfree(wb_ctl);
+}
+
+/* XXX: should be a per-device sysfs attr */
+#define ZRAM_WB_REQ_CNT 32
+
+static struct zram_wb_ctl *init_wb_ctl(void)
+{
+ struct zram_wb_ctl *wb_ctl;
+ int i;
+
+ wb_ctl = kmalloc(sizeof(*wb_ctl), GFP_KERNEL);
+ if (!wb_ctl)
+ return NULL;
+
+ INIT_LIST_HEAD(&wb_ctl->idle_reqs);
+ INIT_LIST_HEAD(&wb_ctl->done_reqs);
+ atomic_set(&wb_ctl->num_inflight, 0);
+ init_waitqueue_head(&wb_ctl->done_wait);
+ spin_lock_init(&wb_ctl->done_lock);
+
+ for (i = 0; i < ZRAM_WB_REQ_CNT; i++) {
+ struct zram_wb_req *req;
+
+ /*
+ * This is fatal condition only if we couldn't allocate
+ * any requests at all. Otherwise we just work with the
+ * requests that we have successfully allocated, so that
+ * writeback can still proceed, even if there is only one
+ * request on the idle list.
+ */
+ req = kzalloc(sizeof(*req), GFP_KERNEL | __GFP_NOWARN);
+ if (!req)
+ break;
+
+ req->page = alloc_page(GFP_KERNEL | __GFP_NOWARN);
+ if (!req->page) {
+ kfree(req);
+ break;
+ }
+
+ list_add(&req->entry, &wb_ctl->idle_reqs);
+ }
+
+ /* We couldn't allocate any requests, so writeabck is not possible */
+ if (list_empty(&wb_ctl->idle_reqs))
+ goto release_wb_ctl;
+
+ return wb_ctl;
+
+release_wb_ctl:
+ release_wb_ctl(wb_ctl);
+ return NULL;
+}
+
+static void zram_account_writeback_rollback(struct zram *zram)
+{
+ spin_lock(&zram->wb_limit_lock);
+ if (zram->wb_limit_enable)
+ zram->bd_wb_limit += 1UL << (PAGE_SHIFT - 12);
+ spin_unlock(&zram->wb_limit_lock);
+}
+
+static void zram_account_writeback_submit(struct zram *zram)
+{
+ spin_lock(&zram->wb_limit_lock);
+ if (zram->wb_limit_enable && zram->bd_wb_limit > 0)
+ zram->bd_wb_limit -= 1UL << (PAGE_SHIFT - 12);
+ spin_unlock(&zram->wb_limit_lock);
+}
+
+static int zram_writeback_complete(struct zram *zram, struct zram_wb_req *req)
+{
+ u32 index = req->pps->index;
+ int err;
+
+ err = blk_status_to_errno(req->bio.bi_status);
+ if (err) {
+ /*
+ * Failed wb requests should not be accounted in wb_limit
+ * (if enabled).
+ */
+ zram_account_writeback_rollback(zram);
+ free_block_bdev(zram, req->blk_idx);
+ return err;
+ }
+
+ atomic64_inc(&zram->stats.bd_writes);
+ zram_slot_lock(zram, index);
+ /*
+ * We release slot lock during writeback so slot can change under us:
+ * slot_free() or slot_free() and zram_write_page(). In both cases
+ * slot loses ZRAM_PP_SLOT flag. No concurrent post-processing can
+ * set ZRAM_PP_SLOT on such slots until current post-processing
+ * finishes.
+ */
+ if (!zram_test_flag(zram, index, ZRAM_PP_SLOT)) {
+ free_block_bdev(zram, req->blk_idx);
+ goto out;
+ }
+
+ zram_free_page(zram, index);
+ zram_set_flag(zram, index, ZRAM_WB);
+ zram_set_handle(zram, index, req->blk_idx);
+ atomic64_inc(&zram->stats.pages_stored);
+
+out:
+ zram_slot_unlock(zram, index);
+ return 0;
+}
+
+static void zram_writeback_endio(struct bio *bio)
+{
+ struct zram_wb_req *req = container_of(bio, struct zram_wb_req, bio);
+ struct zram_wb_ctl *wb_ctl = bio->bi_private;
+ unsigned long flags;
+
+ spin_lock_irqsave(&wb_ctl->done_lock, flags);
+ list_add(&req->entry, &wb_ctl->done_reqs);
+ spin_unlock_irqrestore(&wb_ctl->done_lock, flags);
+
+ wake_up(&wb_ctl->done_wait);
+}
+
+static void zram_submit_wb_request(struct zram *zram,
+ struct zram_wb_ctl *wb_ctl,
+ struct zram_wb_req *req)
+{
+ /*
+ * wb_limit (if enabled) should be adjusted before submission,
+ * so that we don't over-submit.
+ */
+ zram_account_writeback_submit(zram);
+ atomic_inc(&wb_ctl->num_inflight);
+ req->bio.bi_private = wb_ctl;
+ submit_bio(&req->bio);
+}
+
+static int zram_complete_done_reqs(struct zram *zram,
+ struct zram_wb_ctl *wb_ctl)
+{
+ struct zram_wb_req *req;
+ unsigned long flags;
int ret = 0, err;
- u32 index;
- page = alloc_page(GFP_KERNEL);
- if (!page)
- return -ENOMEM;
+ while (atomic_read(&wb_ctl->num_inflight) > 0) {
+ spin_lock_irqsave(&wb_ctl->done_lock, flags);
+ req = list_first_entry_or_null(&wb_ctl->done_reqs,
+ struct zram_wb_req, entry);
+ if (req)
+ list_del(&req->entry);
+ spin_unlock_irqrestore(&wb_ctl->done_lock, flags);
+
+ /* ->num_inflight > 0 doesn't mean we have done requests */
+ if (!req)
+ break;
+
+ err = zram_writeback_complete(zram, req);
+ if (err)
+ ret = err;
+
+ atomic_dec(&wb_ctl->num_inflight);
+ release_pp_slot(zram, req->pps);
+ req->pps = NULL;
+
+ list_add(&req->entry, &wb_ctl->idle_reqs);
+ }
+
+ return ret;
+}
+
+static struct zram_wb_req *zram_select_idle_req(struct zram_wb_ctl *wb_ctl)
+{
+ struct zram_wb_req *req;
+
+ req = list_first_entry_or_null(&wb_ctl->idle_reqs,
+ struct zram_wb_req, entry);
+ if (req)
+ list_del(&req->entry);
+ return req;
+}
+
+static int zram_writeback_slots(struct zram *zram,
+ struct zram_pp_ctl *ctl,
+ struct zram_wb_ctl *wb_ctl)
+{
+ struct zram_wb_req *req = NULL;
+ unsigned long blk_idx = 0;
+ struct zram_pp_slot *pps;
+ int ret = 0, err = 0;
+ u32 index = 0;
while ((pps = select_pp_slot(ctl))) {
spin_lock(&zram->wb_limit_lock);
}
spin_unlock(&zram->wb_limit_lock);
+ while (!req) {
+ req = zram_select_idle_req(wb_ctl);
+ if (req)
+ break;
+
+ wait_event(wb_ctl->done_wait,
+ !list_empty(&wb_ctl->done_reqs));
+
+ err = zram_complete_done_reqs(zram, wb_ctl);
+ /*
+ * BIO errors are not fatal, we continue and simply
+ * attempt to writeback the remaining objects (pages).
+ * At the same time we need to signal user-space that
+ * some writes (at least one, but also could be all of
+ * them) were not successful and we do so by returning
+ * the most recent BIO error.
+ */
+ if (err)
+ ret = err;
+ }
+
if (!blk_idx) {
blk_idx = alloc_block_bdev(zram);
if (!blk_idx) {
*/
if (!zram_test_flag(zram, index, ZRAM_PP_SLOT))
goto next;
- if (zram_read_from_zspool(zram, page, index))
+ if (zram_read_from_zspool(zram, req->page, index))
goto next;
zram_slot_unlock(zram, index);
- bio_init(&bio, zram->bdev, &bio_vec, 1,
- REQ_OP_WRITE | REQ_SYNC);
- bio.bi_iter.bi_sector = blk_idx * (PAGE_SIZE >> 9);
- __bio_add_page(&bio, page, PAGE_SIZE, 0);
-
/*
- * XXX: A single page IO would be inefficient for write
- * but it would be not bad as starter.
+ * From now on pp-slot is owned by the req, remove it from
+ * its pp bucket.
*/
- err = submit_bio_wait(&bio);
- if (err) {
- release_pp_slot(zram, pps);
- /*
- * BIO errors are not fatal, we continue and simply
- * attempt to writeback the remaining objects (pages).
- * At the same time we need to signal user-space that
- * some writes (at least one, but also could be all of
- * them) were not successful and we do so by returning
- * the most recent BIO error.
- */
- ret = err;
- continue;
- }
+ list_del_init(&pps->entry);
- atomic64_inc(&zram->stats.bd_writes);
- zram_slot_lock(zram, index);
- /*
- * Same as above, we release slot lock during writeback so
- * slot can change under us: slot_free() or slot_free() and
- * reallocation (zram_write_page()). In both cases slot loses
- * ZRAM_PP_SLOT flag. No concurrent post-processing can set
- * ZRAM_PP_SLOT on such slots until current post-processing
- * finishes.
- */
- if (!zram_test_flag(zram, index, ZRAM_PP_SLOT))
- goto next;
+ req->blk_idx = blk_idx;
+ req->pps = pps;
+ bio_init(&req->bio, zram->bdev, &req->bio_vec, 1, REQ_OP_WRITE);
+ req->bio.bi_iter.bi_sector = req->blk_idx * (PAGE_SIZE >> 9);
+ req->bio.bi_end_io = zram_writeback_endio;
+ __bio_add_page(&req->bio, req->page, PAGE_SIZE, 0);
- zram_free_page(zram, index);
- zram_set_flag(zram, index, ZRAM_WB);
- zram_set_handle(zram, index, blk_idx);
+ zram_submit_wb_request(zram, wb_ctl, req);
blk_idx = 0;
- atomic64_inc(&zram->stats.pages_stored);
- spin_lock(&zram->wb_limit_lock);
- if (zram->wb_limit_enable && zram->bd_wb_limit > 0)
- zram->bd_wb_limit -= 1UL << (PAGE_SHIFT - 12);
- spin_unlock(&zram->wb_limit_lock);
+ req = NULL;
+ cond_resched();
+ continue;
+
next:
zram_slot_unlock(zram, index);
release_pp_slot(zram, pps);
-
- cond_resched();
}
- if (blk_idx)
- free_block_bdev(zram, blk_idx);
- if (page)
- __free_page(page);
+ /*
+ * Selected idle req, but never submitted it due to some error or
+ * wb limit.
+ */
+ if (req)
+ release_wb_req(req);
+
+ while (atomic_read(&wb_ctl->num_inflight) > 0) {
+ wait_event(wb_ctl->done_wait, !list_empty(&wb_ctl->done_reqs));
+ err = zram_complete_done_reqs(zram, wb_ctl);
+ if (err)
+ ret = err;
+ }
return ret;
}
struct zram *zram = dev_to_zram(dev);
u64 nr_pages = zram->disksize >> PAGE_SHIFT;
unsigned long lo = 0, hi = nr_pages;
- struct zram_pp_ctl *ctl = NULL;
+ struct zram_pp_ctl *pp_ctl = NULL;
+ struct zram_wb_ctl *wb_ctl = NULL;
char *args, *param, *val;
ssize_t ret = len;
int err, mode = 0;
goto release_init_lock;
}
- ctl = init_pp_ctl();
- if (!ctl) {
+ pp_ctl = init_pp_ctl();
+ if (!pp_ctl) {
+ ret = -ENOMEM;
+ goto release_init_lock;
+ }
+
+ wb_ctl = init_wb_ctl();
+ if (!wb_ctl) {
ret = -ENOMEM;
goto release_init_lock;
}
goto release_init_lock;
}
- scan_slots_for_writeback(zram, mode, lo, hi, ctl);
+ scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl);
break;
}
goto release_init_lock;
}
- scan_slots_for_writeback(zram, mode, lo, hi, ctl);
+ scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl);
break;
}
goto release_init_lock;
}
- scan_slots_for_writeback(zram, mode, lo, hi, ctl);
+ scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl);
continue;
}
goto release_init_lock;
}
- scan_slots_for_writeback(zram, mode, lo, hi, ctl);
+ scan_slots_for_writeback(zram, mode, lo, hi, pp_ctl);
continue;
}
}
- err = zram_writeback_slots(zram, ctl);
+ err = zram_writeback_slots(zram, pp_ctl, wb_ctl);
if (err)
ret = err;
release_init_lock:
- release_pp_ctl(zram, ctl);
+ release_pp_ctl(zram, pp_ctl);
+ release_wb_ctl(wb_ctl);
atomic_set(&zram->pp_in_progress, 0);
up_read(&zram->init_lock);
return -EIO;
}
-static void free_block_bdev(struct zram *zram, unsigned long blk_idx) {};
+static void free_block_bdev(struct zram *zram, unsigned long blk_idx)
+{
+}
#endif
#ifdef CONFIG_ZRAM_MEMORY_TRACKING
projects / thirdparty / linux.git / commitdiff
