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author | Lars Ellenberg <lars.ellenberg@linbit.com> | 2013-03-19 18:16:56 +0100 |
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committer | Jens Axboe <axboe@kernel.dk> | 2013-03-22 22:18:09 -0600 |
commit | 08a1ddab6df7d3c7b6341774cb1cf4b21b96a214 (patch) | |
tree | 6e8aec1506b8e3f2f7215a2043518d9b35f90ddf /drivers/block/drbd/drbd_actlog.c | |
parent | cbe5e6109538ddab57764a88d9f0c2accd0c7d48 (diff) | |
download | op-kernel-dev-08a1ddab6df7d3c7b6341774cb1cf4b21b96a214.zip op-kernel-dev-08a1ddab6df7d3c7b6341774cb1cf4b21b96a214.tar.gz |
drbd: consolidate as many updates as possible into one AL transaction
Depending on current IO depth, try to consolidate as many updates
as possible into one activity log transaction.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'drivers/block/drbd/drbd_actlog.c')
-rw-r--r-- | drivers/block/drbd/drbd_actlog.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c index ff03f90..6afe173 100644 --- a/drivers/block/drbd/drbd_actlog.c +++ b/drivers/block/drbd/drbd_actlog.c @@ -359,6 +359,55 @@ void drbd_al_begin_io(struct drbd_conf *mdev, struct drbd_interval *i, bool dele drbd_al_begin_io_commit(mdev, delegate); } +int drbd_al_begin_io_nonblock(struct drbd_conf *mdev, struct drbd_interval *i) +{ + struct lru_cache *al = mdev->act_log; + /* for bios crossing activity log extent boundaries, + * we may need to activate two extents in one go */ + unsigned first = i->sector >> (AL_EXTENT_SHIFT-9); + unsigned last = i->size == 0 ? first : (i->sector + (i->size >> 9) - 1) >> (AL_EXTENT_SHIFT-9); + unsigned nr_al_extents; + unsigned available_update_slots; + unsigned enr; + + D_ASSERT(first <= last); + + nr_al_extents = 1 + last - first; /* worst case: all touched extends are cold. */ + available_update_slots = min(al->nr_elements - al->used, + al->max_pending_changes - al->pending_changes); + + /* We want all necessary updates for a given request within the same transaction + * We could first check how many updates are *actually* needed, + * and use that instead of the worst-case nr_al_extents */ + if (available_update_slots < nr_al_extents) + return -EWOULDBLOCK; + + /* Is resync active in this area? */ + for (enr = first; enr <= last; enr++) { + struct lc_element *tmp; + tmp = lc_find(mdev->resync, enr/AL_EXT_PER_BM_SECT); + if (unlikely(tmp != NULL)) { + struct bm_extent *bm_ext = lc_entry(tmp, struct bm_extent, lce); + if (test_bit(BME_NO_WRITES, &bm_ext->flags)) { + if (!test_and_set_bit(BME_PRIORITY, &bm_ext->flags)); + return -EBUSY; + return -EWOULDBLOCK; + } + } + } + + /* Checkout the refcounts. + * Given that we checked for available elements and update slots above, + * this has to be successful. */ + for (enr = first; enr <= last; enr++) { + struct lc_element *al_ext; + al_ext = lc_get_cumulative(mdev->act_log, enr); + if (!al_ext) + dev_info(DEV, "LOGIC BUG for enr=%u\n", enr); + } + return 0; +} + void drbd_al_complete_io(struct drbd_conf *mdev, struct drbd_interval *i) { /* for bios crossing activity log extent boundaries, |