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writeback: move backing_dev_info->state into bdi_writeback

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Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback)
and the role of the separation is unclear.  For cgroup support for
writeback IOs, a bdi will be updated to host multiple wb's where each
wb serves writeback IOs of a different cgroup on the bdi.  To achieve
that, a wb should carry all states necessary for servicing writeback
IOs for a cgroup independently.

This patch moves bdi->state into wb.

* enum bdi_state is renamed to wb_state and the prefix of all enums is
  changed from BDI_ to WB_.

* Explicit zeroing of bdi->state is removed without adding zeoring of
  wb->state as the whole data structure is zeroed on init anyway.

* As there's still only one bdi_writeback per backing_dev_info, all
  uses of bdi->state are mechanically replaced with bdi->wb.state
  introducing no behavior changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: drbd-dev@lists.linbit.com
Cc: Neil Brown <neilb@suse.de>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Tejun Heo 2015-05-22 17:13:26 -04:00 • committed by Jens Axboe
parent ad7fa852d3
commit 4452226ea2
8 changed files with 38 additions and 39 deletions
Download patch file Download diff file Expand all files Collapse all files

24
include/linux/backing-dev.h
View file

@ -25,13 +25,13 @@ struct device;
struct dentry;
/*
* Bits in backing_dev_info.state
* Bits in bdi_writeback.state
*/
enum bdi_state {
BDI_async_congested, /* The async (write) queue is getting full */
BDI_sync_congested, /* The sync queue is getting full */
BDI_registered, /* bdi_register() was done */
BDI_writeback_running, /* Writeback is in progress */
enum wb_state {
WB_async_congested, /* The async (write) queue is getting full */
WB_sync_congested, /* The sync queue is getting full */
WB_registered, /* bdi_register() was done */
WB_writeback_running, /* Writeback is in progress */
};
typedef int (congested_fn)(void *, int);
@ -49,6 +49,7 @@ enum bdi_stat_item {
struct bdi_writeback {
struct backing_dev_info *bdi; /* our parent bdi */
unsigned long state; /* Always use atomic bitops on this */
unsigned long last_old_flush; /* last old data flush */
struct delayed_work dwork; /* work item used for writeback */
@ -62,7 +63,6 @@ struct bdi_writeback {
struct backing_dev_info {
struct list_head bdi_list;
unsigned long ra_pages; /* max readahead in PAGE_CACHE_SIZE units */
unsigned long state; /* Always use atomic bitops on this */
unsigned int capabilities; /* Device capabilities */
congested_fn *congested_fn; /* Function pointer if device is md/dm */
void *congested_data; /* Pointer to aux data for congested func */
@ -250,23 +250,23 @@ static inline int bdi_congested(struct backing_dev_info *bdi, int bdi_bits)
{
if (bdi->congested_fn)
return bdi->congested_fn(bdi->congested_data, bdi_bits);
return (bdi->state & bdi_bits);
return (bdi->wb.state & bdi_bits);
}
static inline int bdi_read_congested(struct backing_dev_info *bdi)
{
return bdi_congested(bdi, 1 << BDI_sync_congested);
return bdi_congested(bdi, 1 << WB_sync_congested);
}
static inline int bdi_write_congested(struct backing_dev_info *bdi)
{
return bdi_congested(bdi, 1 << BDI_async_congested);
return bdi_congested(bdi, 1 << WB_async_congested);
}
static inline int bdi_rw_congested(struct backing_dev_info *bdi)
{
return bdi_congested(bdi, (1 << BDI_sync_congested) |
(1 << BDI_async_congested));
return bdi_congested(bdi, (1 << WB_sync_congested) |
(1 << WB_async_congested));
}
enum {