[PATCH 10/23] drbd: track details of bitmap IO

From: Philipp Reisner
Date: Thu Jul 03 2014 - 04:52:23 EST

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From: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>

Track start and submit time of bitmap operations, and
add pending bitmap IO contexts to a new pending_bitmap_io list.

Signed-off-by: Philipp Reisner <philipp.reisner@xxxxxxxxxx>
Signed-off-by: Lars Ellenberg <lars.ellenberg@xxxxxxxxxx>
---
drivers/block/drbd/drbd_bitmap.c | 70 +++++++++++++++++++---------------------
drivers/block/drbd/drbd_int.h | 16 +++++++++
drivers/block/drbd/drbd_main.c | 1 +
3 files changed, 51 insertions(+), 36 deletions(-)

diff --git a/drivers/block/drbd/drbd_bitmap.c b/drivers/block/drbd/drbd_bitmap.c
index c5f5a20..f435e7e 100644
--- a/drivers/block/drbd/drbd_bitmap.c
+++ b/drivers/block/drbd/drbd_bitmap.c
@@ -928,22 +928,14 @@ void drbd_bm_clear_all(struct drbd_device *device)
spin_unlock_irq(&b->bm_lock);
}

-struct bm_aio_ctx {
- struct drbd_device *device;
- atomic_t in_flight;
- unsigned int done;
- unsigned flags;
-#define BM_AIO_COPY_PAGES 1
-#define BM_AIO_WRITE_HINTED 2
-#define BM_WRITE_ALL_PAGES 4
- int error;
- struct kref kref;
-};
-
-static void bm_aio_ctx_destroy(struct kref *kref)
+static void drbd_bm_aio_ctx_destroy(struct kref *kref)
{
- struct bm_aio_ctx *ctx = container_of(kref, struct bm_aio_ctx, kref);
+ struct drbd_bm_aio_ctx *ctx = container_of(kref, struct drbd_bm_aio_ctx, kref);
+ unsigned long flags;

+ spin_lock_irqsave(&ctx->device->resource->req_lock, flags);
+ list_del(&ctx->list);
+ spin_unlock_irqrestore(&ctx->device->resource->req_lock, flags);
put_ldev(ctx->device);
kfree(ctx);
}
@@ -951,7 +943,7 @@ static void bm_aio_ctx_destroy(struct kref *kref)
/* bv_page may be a copy, or may be the original */
static void bm_async_io_complete(struct bio *bio, int error)
{
- struct bm_aio_ctx *ctx = bio->bi_private;
+ struct drbd_bm_aio_ctx *ctx = bio->bi_private;
struct drbd_device *device = ctx->device;
struct drbd_bitmap *b = device->bitmap;
unsigned int idx = bm_page_to_idx(bio->bi_io_vec[0].bv_page);
@@ -994,17 +986,18 @@ static void bm_async_io_complete(struct bio *bio, int error)
if (atomic_dec_and_test(&ctx->in_flight)) {
ctx->done = 1;
wake_up(&device->misc_wait);
- kref_put(&ctx->kref, &bm_aio_ctx_destroy);
+ kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy);
}
}

-static void bm_page_io_async(struct bm_aio_ctx *ctx, int page_nr, int rw) __must_hold(local)
+static void bm_page_io_async(struct drbd_bm_aio_ctx *ctx, int page_nr) __must_hold(local)
{
struct bio *bio = bio_alloc_drbd(GFP_NOIO);
struct drbd_device *device = ctx->device;
struct drbd_bitmap *b = device->bitmap;
struct page *page;
unsigned int len;
+ unsigned int rw = (ctx->flags & BM_AIO_READ) ? READ : WRITE;

sector_t on_disk_sector =
device->ldev->md.md_offset + device->ldev->md.bm_offset;
@@ -1050,9 +1043,9 @@ static void bm_page_io_async(struct bm_aio_ctx *ctx, int page_nr, int rw) __must
/*
* bm_rw: read/write the whole bitmap from/to its on disk location.
*/
-static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned lazy_writeout_upper_idx) __must_hold(local)
+static int bm_rw(struct drbd_device *device, const unsigned int flags, unsigned lazy_writeout_upper_idx) __must_hold(local)
{
- struct bm_aio_ctx *ctx;
+ struct drbd_bm_aio_ctx *ctx;
struct drbd_bitmap *b = device->bitmap;
int num_pages, i, count = 0;
unsigned long now;
@@ -1068,12 +1061,13 @@ static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned la
* as we submit copies of pages anyways.
*/

- ctx = kmalloc(sizeof(struct bm_aio_ctx), GFP_NOIO);
+ ctx = kmalloc(sizeof(struct drbd_bm_aio_ctx), GFP_NOIO);
if (!ctx)
return -ENOMEM;

- *ctx = (struct bm_aio_ctx) {
+ *ctx = (struct drbd_bm_aio_ctx) {
.device = device,
+ .start_jif = jiffies,
.in_flight = ATOMIC_INIT(1),
.done = 0,
.flags = flags,
@@ -1081,7 +1075,7 @@ static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned la
.kref = { ATOMIC_INIT(2) },
};

- if (!get_ldev_if_state(device, D_ATTACHING)) { /* put is in bm_aio_ctx_destroy() */
+ if (!get_ldev_if_state(device, D_ATTACHING)) { /* put is in drbd_bm_aio_ctx_destroy() */
drbd_err(device, "ASSERT FAILED: get_ldev_if_state() == 1 in bm_rw()\n");
kfree(ctx);
return -ENODEV;
@@ -1089,9 +1083,13 @@ static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned la
/* Here D_ATTACHING is sufficient since drbd_bm_read() is called only from
drbd_adm_attach(), after device->ldev was assigned. */

- if (!ctx->flags)
+ if (0 == (ctx->flags & ~BM_AIO_READ))
WARN_ON(!(BM_LOCKED_MASK & b->bm_flags));

+ spin_lock_irq(&device->resource->req_lock);
+ list_add_tail(&ctx->list, &device->pending_bitmap_io);
+ spin_unlock_irq(&device->resource->req_lock);
+
num_pages = b->bm_number_of_pages;

now = jiffies;
@@ -1101,13 +1099,13 @@ static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned la
/* ignore completely unchanged pages */
if (lazy_writeout_upper_idx && i == lazy_writeout_upper_idx)
break;
- if (rw & WRITE) {
+ if (!(flags & BM_AIO_READ)) {
if ((flags & BM_AIO_WRITE_HINTED) &&
!test_and_clear_bit(BM_PAGE_HINT_WRITEOUT,
&page_private(b->bm_pages[i])))
continue;

- if (!(flags & BM_WRITE_ALL_PAGES) &&
+ if (!(flags & BM_AIO_WRITE_ALL_PAGES) &&
bm_test_page_unchanged(b->bm_pages[i])) {
dynamic_drbd_dbg(device, "skipped bm write for idx %u\n", i);
continue;
@@ -1121,7 +1119,7 @@ static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned la
}
}
atomic_inc(&ctx->in_flight);
- bm_page_io_async(ctx, i, rw);
+ bm_page_io_async(ctx, i);
++count;
cond_resched();
}
@@ -1137,12 +1135,12 @@ static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned la
if (!atomic_dec_and_test(&ctx->in_flight))
wait_until_done_or_force_detached(device, device->ldev, &ctx->done);
else
- kref_put(&ctx->kref, &bm_aio_ctx_destroy);
+ kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy);

/* summary for global bitmap IO */
if (flags == 0)
drbd_info(device, "bitmap %s of %u pages took %lu jiffies\n",
- rw == WRITE ? "WRITE" : "READ",
+ (flags & BM_AIO_READ) ? "READ" : "WRITE",
count, jiffies - now);

if (ctx->error) {
@@ -1155,18 +1153,18 @@ static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned la
err = -EIO; /* Disk timeout/force-detach during IO... */

now = jiffies;
- if (rw == READ) {
+ if (flags & BM_AIO_READ) {
b->bm_set = bm_count_bits(b);
drbd_info(device, "recounting of set bits took additional %lu jiffies\n",
jiffies - now);
}
now = b->bm_set;

- if (flags == 0)
+ if ((flags & ~BM_AIO_READ) == 0)
drbd_info(device, "%s (%lu bits) marked out-of-sync by on disk bit-map.\n",
ppsize(ppb, now << (BM_BLOCK_SHIFT-10)), now);

- kref_put(&ctx->kref, &bm_aio_ctx_destroy);
+ kref_put(&ctx->kref, &drbd_bm_aio_ctx_destroy);
return err;
}

@@ -1176,7 +1174,7 @@ static int bm_rw(struct drbd_device *device, int rw, unsigned flags, unsigned la
*/
int drbd_bm_read(struct drbd_device *device) __must_hold(local)
{
- return bm_rw(device, READ, 0, 0);
+ return bm_rw(device, BM_AIO_READ, 0);
}

/**
@@ -1187,7 +1185,7 @@ int drbd_bm_read(struct drbd_device *device) __must_hold(local)
*/
int drbd_bm_write(struct drbd_device *device) __must_hold(local)
{
- return bm_rw(device, WRITE, 0, 0);
+ return bm_rw(device, 0, 0);
}

/**
@@ -1198,7 +1196,7 @@ int drbd_bm_write(struct drbd_device *device) __must_hold(local)
*/
int drbd_bm_write_all(struct drbd_device *device) __must_hold(local)
{
- return bm_rw(device, WRITE, BM_WRITE_ALL_PAGES, 0);
+ return bm_rw(device, BM_AIO_WRITE_ALL_PAGES, 0);
}

/**
@@ -1214,7 +1212,7 @@ int drbd_bm_write_all(struct drbd_device *device) __must_hold(local)
*/
int drbd_bm_write_copy_pages(struct drbd_device *device) __must_hold(local)
{
- return bm_rw(device, WRITE, BM_AIO_COPY_PAGES, 0);
+ return bm_rw(device, BM_AIO_COPY_PAGES, 0);
}

/**
@@ -1223,7 +1221,7 @@ int drbd_bm_write_copy_pages(struct drbd_device *device) __must_hold(local)
*/
int drbd_bm_write_hinted(struct drbd_device *device) __must_hold(local)
{
- return bm_rw(device, WRITE, BM_AIO_WRITE_HINTED | BM_AIO_COPY_PAGES, 0);
+ return bm_rw(device, BM_AIO_WRITE_HINTED | BM_AIO_COPY_PAGES, 0);
}

/* NOTE
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index c7a409f..40c816c 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -777,6 +777,7 @@ struct drbd_peer_device {
struct drbd_device {
struct drbd_resource *resource;
struct list_head peer_devices;
+ struct list_head pending_bitmap_io;
int vnr; /* volume number within the connection */
struct kref kref;

@@ -918,6 +919,21 @@ struct drbd_device {
struct submit_worker submit;
};

+struct drbd_bm_aio_ctx {
+ struct drbd_device *device;
+ struct list_head list; /* on device->pending_bitmap_io */;
+ unsigned long start_jif;
+ atomic_t in_flight;
+ unsigned int done;
+ unsigned flags;
+#define BM_AIO_COPY_PAGES 1
+#define BM_AIO_WRITE_HINTED 2
+#define BM_AIO_WRITE_ALL_PAGES 4
+#define BM_AIO_READ 8
+ int error;
+ struct kref kref;
+};
+
struct drbd_config_context {
/* assigned from drbd_genlmsghdr */
unsigned int minor;
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index ad7c0e8..922d631 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2793,6 +2793,7 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
kref_get(&device->kref);

INIT_LIST_HEAD(&device->peer_devices);
+ INIT_LIST_HEAD(&device->pending_bitmap_io);
for_each_connection(connection, resource) {
peer_device = kzalloc(sizeof(struct drbd_peer_device), GFP_KERNEL);
if (!peer_device)
--
1.9.1

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Next message: Philipp Reisner: "[PATCH 02/23] drbd: fix drbd_destroy_device reference count updates"
Previous message: Philipp Reisner: "[PATCH 09/23] drbd: register peer requests on read_ee early"
In reply to: Philipp Reisner: "[PATCH 09/23] drbd: register peer requests on read_ee early"
Next in thread: Philipp Reisner: "[PATCH 02/23] drbd: fix drbd_destroy_device reference count updates"
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