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authorTejun Heo <tj@kernel.org>2015-05-23 00:13:35 +0300
committerJens Axboe <axboe@fb.com>2015-06-02 17:33:35 +0300
commit4aa9c692e052cf6db99db62a8fe0543e5c455da7 (patch)
tree378d5b44e7ec769dd4dfc9ac5ab2447fdb1f50a4 /mm/backing-dev.c
parent8395cd9f813d5d7ed9870e642230acfcfc1e8a0a (diff)
downloadlinux-4aa9c692e052cf6db99db62a8fe0543e5c455da7.tar.xz
bdi: separate out congested state into a separate struct
Currently, a wb's (bdi_writeback) congestion state is carried in its ->state field; however, cgroup writeback support will require multiple wb's sharing the same congestion state. This patch separates out congestion state into its own struct - struct bdi_writeback_congested. A new field wb field, wb_congested, points to its associated congested struct. The default wb, bdi->wb, always points to bdi->wb_congested. While this patch adds a layer of indirection, it doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'mm/backing-dev.c')
-rw-r--r--mm/backing-dev.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 805b2870ca4e..5ec7658cb984 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -383,6 +383,9 @@ int bdi_init(struct backing_dev_info *bdi)
if (err)
return err;
+ bdi->wb_congested.state = 0;
+ bdi->wb.congested = &bdi->wb_congested;
+
return 0;
}
EXPORT_SYMBOL(bdi_init);
@@ -504,7 +507,7 @@ void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
wait_queue_head_t *wqh = &congestion_wqh[sync];
bit = sync ? WB_sync_congested : WB_async_congested;
- if (test_and_clear_bit(bit, &bdi->wb.state))
+ if (test_and_clear_bit(bit, &bdi->wb.congested->state))
atomic_dec(&nr_bdi_congested[sync]);
smp_mb__after_atomic();
if (waitqueue_active(wqh))
@@ -517,7 +520,7 @@ void set_bdi_congested(struct backing_dev_info *bdi, int sync)
enum wb_state bit;
bit = sync ? WB_sync_congested : WB_async_congested;
- if (!test_and_set_bit(bit, &bdi->wb.state))
+ if (!test_and_set_bit(bit, &bdi->wb.congested->state))
atomic_inc(&nr_bdi_congested[sync]);
}
EXPORT_SYMBOL(set_bdi_congested);