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SubjectRe: [Drbd-dev] [PATCH 016/118] drbd: Add read_requests tree
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Am Donnerstag, 25. August 2011, 20:02:44 schrieb Pawel Jakub Dawidek:
> On Thu, Aug 25, 2011 at 05:07:12PM +0200, Philipp Reisner wrote:
> > From: Andreas Gruenbacher <agruen@linbit.com>
> >
> > We do not do collision detection for read requests, but we still need to
> > look up the request objects when we receive a package over the network.
> > Using the same data structure for read and write requests results in
> > simpler code once the tl_hash and app_reads_hash tables are removed.
> >
> > Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
> > Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
> > ---
> >
> > drivers/block/drbd/drbd_int.h | 1 +
> > drivers/block/drbd/drbd_main.c | 1 +
> > drivers/block/drbd/drbd_req.c | 13 ++++++++++---
> > 3 files changed, 12 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/block/drbd/drbd_int.h
> > b/drivers/block/drbd/drbd_int.h index 0583713..fe15319 100644
> > --- a/drivers/block/drbd/drbd_int.h
> > +++ b/drivers/block/drbd/drbd_int.h
> > @@ -1020,6 +1020,7 @@ struct drbd_conf {
> >
> > unsigned int tl_hash_s;
> >
> > /* Interval tree of pending local write requests */
> >
> > + struct rb_root read_requests;
> >
> > struct rb_root write_requests;
>
> Looks like the comment needs updating.

Ok, new edition of the patch:

From dac1389ccc273b5486f2931c64c8e1672f233727 Mon Sep 17 00:00:00 2001
From: Andreas Gruenbacher <agruen@linbit.com>
Date: Fri, 21 Jan 2011 17:18:39 +0100
Subject: [PATCH 016/118] drbd: Add read_requests tree

We do not do collision detection for read requests, but we still need to
look up the request objects when we receive a package over the network.
Using the same data structure for read and write requests results in
simpler code once the tl_hash and app_reads_hash tables are removed.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
---
drivers/block/drbd/drbd_int.h | 3 ++-
drivers/block/drbd/drbd_main.c | 1 +
drivers/block/drbd/drbd_req.c | 13 ++++++++++---
3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 0583713..46a4332 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -1019,7 +1019,8 @@ struct drbd_conf {
struct hlist_head *tl_hash;
unsigned int tl_hash_s;

- /* Interval tree of pending local write requests */
+ /* Interval tree of pending local requests */
+ struct rb_root read_requests;
struct rb_root write_requests;

/* blocks to resync in this run [unit BM_BLOCK_SIZE] */
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 4d85838..c0ea5ba 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -3473,6 +3473,7 @@ struct drbd_conf *drbd_new_device(unsigned int minor)
/* no need to lock access, we are still initializing this minor device. */
if (!tl_init(mdev))
goto out_no_tl;
+ mdev->read_requests = RB_ROOT;
mdev->write_requests = RB_ROOT;

mdev->app_reads_hash = kzalloc(APP_R_HSIZE*sizeof(void *), GFP_KERNEL);
diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
index 593576f..d2a78c4 100644
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -260,10 +260,15 @@ void _req_may_be_done(struct drbd_request *req, struct bio_and_error *m)

/* remove the request from the conflict detection
* respective block_id verification hash */
- if (!hlist_unhashed(&req->collision)) {
+ if (!drbd_interval_empty(&req->i)) {
+ struct rb_root *root;
+
hlist_del(&req->collision);
- if (!drbd_interval_empty(&req->i))
- drbd_remove_interval(&mdev->write_requests, &req->i);
+ if (rw == WRITE)
+ root = &mdev->write_requests;
+ else
+ root = &mdev->read_requests;
+ drbd_remove_interval(root, &req->i);
} else
D_ASSERT((s & (RQ_NET_MASK & ~RQ_NET_DONE)) == 0);

@@ -332,6 +337,7 @@ static int _req_conflicts(struct drbd_request *req)
struct hlist_head *slot;

D_ASSERT(hlist_unhashed(&req->collision));
+ D_ASSERT(drbd_interval_empty(&req->i));

if (!get_net_conf(mdev))
return 0;
@@ -493,6 +499,7 @@ int __req_mod(struct drbd_request *req, enum drbd_req_event what,
/* so we can verify the handle in the answer packet
* corresponding hlist_del is in _req_may_be_done() */
hlist_add_head(&req->collision, ar_hash_slot(mdev, req->i.sector));
+ drbd_insert_interval(&mdev->read_requests, &req->i);

set_bit(UNPLUG_REMOTE, &mdev->flags);

--
1.7.4.1
--
: Dipl-Ing Philipp Reisner
: LINBIT | Your Way to High Availability
: Tel: +43-1-8178292-50, Fax: +43-1-8178292-82
: http://www.linbit.com

DRBD(R) and LINBIT(R) are registered trademarks of LINBIT, Austria.


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