On Thu, 2022-01-27 at 13:46 +1100, NeilBrown wrote:
> The bdi congestion framework is no-longer used - writeback uses other
> mechanisms to manage throughput.
>
> So remove calls to set_bdi_congested() and clear_bdi_congested(), and
> remove the writeback_count which is used only to guide the setting and
> clearing.
>
> The congestion_kb mount option is no longer meaningful, but as it is
> visible to user-space, removing it needs more consideration.
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
> ---
> fs/ceph/addr.c | 27 ---------------------------
> fs/ceph/super.c | 2 --
> fs/ceph/super.h | 2 --
> 3 files changed, 31 deletions(-)
>
> diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
> index c98e5238a1b6..9147667f8cd5 100644
> --- a/fs/ceph/addr.c
> +++ b/fs/ceph/addr.c
> @@ -57,11 +57,6 @@
> * accounting is preserved.
> */
>
> -#define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
> -#define CONGESTION_OFF_THRESH(congestion_kb) \
> - (CONGESTION_ON_THRESH(congestion_kb) - \
> - (CONGESTION_ON_THRESH(congestion_kb) >> 2))
> -
> static int ceph_netfs_check_write_begin(struct file *file, loff_t pos, unsigned int len,
> struct folio *folio, void **_fsdata);
>
> @@ -561,10 +556,6 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
> dout("writepage %p page %p index %lu on %llu~%llu snapc %p seq %lld\n",
> inode, page, page->index, page_off, len, snapc, snapc->seq);
>
> - if (atomic_long_inc_return(&fsc->writeback_count) >
> - CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb))
> - set_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
> -
> req = ceph_osdc_new_request(osdc, &ci->i_layout, ceph_vino(inode), page_off, &len, 0, 1,
> CEPH_OSD_OP_WRITE, CEPH_OSD_FLAG_WRITE, snapc,
> ceph_wbc.truncate_seq, ceph_wbc.truncate_size,
> @@ -621,10 +612,6 @@ static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
> ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
> ceph_put_snap_context(snapc); /* page's reference */
>
> - if (atomic_long_dec_return(&fsc->writeback_count) <
> - CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb))
> - clear_bdi_congested(inode_to_bdi(inode), BLK_RW_ASYNC);
> -
> return err;
> }
>
> @@ -704,12 +691,6 @@ static void writepages_finish(struct ceph_osd_request *req)
> BUG_ON(!page);
> WARN_ON(!PageUptodate(page));
>
> - if (atomic_long_dec_return(&fsc->writeback_count) <
> - CONGESTION_OFF_THRESH(
> - fsc->mount_options->congestion_kb))
> - clear_bdi_congested(inode_to_bdi(inode),
> - BLK_RW_ASYNC);
> -
> ceph_put_snap_context(detach_page_private(page));
> end_page_writeback(page);
> dout("unlocking %p\n", page);
> @@ -952,14 +933,6 @@ static int ceph_writepages_start(struct address_space *mapping,
> dout("%p will write page %p idx %lu\n",
> inode, page, page->index);
>
> - if (atomic_long_inc_return(&fsc->writeback_count) >
> - CONGESTION_ON_THRESH(
> - fsc->mount_options->congestion_kb)) {
> - set_bdi_congested(inode_to_bdi(inode),
> - BLK_RW_ASYNC);
> - }
> -
> -
> pages[locked_pages++] = page;
> pvec.pages[i] = NULL;
>
> diff --git a/fs/ceph/super.c b/fs/ceph/super.c
> index bf79f369aec6..b2f38af9fca8 100644
> --- a/fs/ceph/super.c
> +++ b/fs/ceph/super.c
> @@ -801,8 +801,6 @@ static struct ceph_fs_client *create_fs_client(struct ceph_mount_options *fsopt,
> fsc->filp_gen = 1;
> fsc->have_copy_from2 = true;
>
> - atomic_long_set(&fsc->writeback_count, 0);
> -
> err = -ENOMEM;
> /*
> * The number of concurrent works can be high but they don't need
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index 67f145e1ae7a..fc58adf1d36a 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -120,8 +120,6 @@ struct ceph_fs_client {
>
> struct ceph_mds_client *mdsc;
>
> - atomic_long_t writeback_count;
> -
> struct workqueue_struct *inode_wq;
> struct workqueue_struct *cap_wq;
>
>
>
Thanks Neil.
I'll plan to pull this into the ceph testing branch and do some testing
with it, but at a quick glance I don't forsee any issues. This should
make v5.18, but we may be able to get it in sooner.
--
Jeff Layton <jlayton@xxxxxxxxxx>
