| Message ID | 20190815195902.GE2263813@devbig004.ftw2.facebook.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/5] writeback: Generalize and expose wb_completion | expand |
On Thu 15-08-19 12:59:02, Tejun Heo wrote: > Implement cgroup_writeback_by_id() which initiates cgroup writeback > from bdi and memcg IDs. This will be used by memcg foreign inode > flushing. > > Signed-off-by: Tejun Heo <tj@kernel.org> Looks good to me. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/fs-writeback.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/writeback.h | 2 + > 2 files changed, 69 insertions(+) > > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -892,6 +892,73 @@ restart: > } > > /** > + * cgroup_writeback_by_id - initiate cgroup writeback from bdi and memcg IDs > + * @bdi_id: target bdi id > + * @memcg_id: target memcg css id > + * @nr_pages: number of pages to write > + * @reason: reason why some writeback work initiated > + * @done: target wb_completion > + * > + * Initiate flush of the bdi_writeback identified by @bdi_id and @memcg_id > + * with the specified parameters. > + */ > +int cgroup_writeback_by_id(u64 bdi_id, int memcg_id, unsigned long nr, > + enum wb_reason reason, struct wb_completion *done) > +{ > + struct backing_dev_info *bdi; > + struct cgroup_subsys_state *memcg_css; > + struct bdi_writeback *wb; > + struct wb_writeback_work *work; > + int ret; > + > + /* lookup bdi and memcg */ > + bdi = bdi_get_by_id(bdi_id); > + if (!bdi) > + return -ENOENT; > + > + rcu_read_lock(); > + memcg_css = css_from_id(memcg_id, &memory_cgrp_subsys); > + if (memcg_css && !css_tryget(memcg_css)) > + memcg_css = NULL; > + rcu_read_unlock(); > + if (!memcg_css) { > + ret = -ENOENT; > + goto out_bdi_put; > + } > + > + /* > + * And find the associated wb. If the wb isn't there already > + * there's nothing to flush, don't create one. > + */ > + wb = wb_get_lookup(bdi, memcg_css); > + if (!wb) { > + ret = -ENOENT; > + goto out_css_put; > + } > + > + /* issue the writeback work */ > + work = kzalloc(sizeof(*work), GFP_NOWAIT | __GFP_NOWARN); > + if (work) { > + work->nr_pages = nr; > + work->sync_mode = WB_SYNC_NONE; > + work->reason = reason; > + work->done = done; > + work->auto_free = 1; > + wb_queue_work(wb, work); > + ret = 0; > + } else { > + ret = -ENOMEM; > + } > + > + wb_put(wb); > +out_css_put: > + css_put(memcg_css); > +out_bdi_put: > + bdi_put(bdi); > + return ret; > +} > + > +/** > * cgroup_writeback_umount - flush inode wb switches for umount > * > * This function is called when a super_block is about to be destroyed and > --- a/include/linux/writeback.h > +++ b/include/linux/writeback.h > @@ -217,6 +217,8 @@ void wbc_attach_and_unlock_inode(struct > void wbc_detach_inode(struct writeback_control *wbc); > void wbc_account_cgroup_owner(struct writeback_control *wbc, struct page *page, > size_t bytes); > +int cgroup_writeback_by_id(u64 bdi_id, int memcg_id, unsigned long nr_pages, > + enum wb_reason reason, struct wb_completion *done); > void cgroup_writeback_umount(void); > > /**
--- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -892,6 +892,73 @@ restart: } /** + * cgroup_writeback_by_id - initiate cgroup writeback from bdi and memcg IDs + * @bdi_id: target bdi id + * @memcg_id: target memcg css id + * @nr_pages: number of pages to write + * @reason: reason why some writeback work initiated + * @done: target wb_completion + * + * Initiate flush of the bdi_writeback identified by @bdi_id and @memcg_id + * with the specified parameters. + */ +int cgroup_writeback_by_id(u64 bdi_id, int memcg_id, unsigned long nr, + enum wb_reason reason, struct wb_completion *done) +{ + struct backing_dev_info *bdi; + struct cgroup_subsys_state *memcg_css; + struct bdi_writeback *wb; + struct wb_writeback_work *work; + int ret; + + /* lookup bdi and memcg */ + bdi = bdi_get_by_id(bdi_id); + if (!bdi) + return -ENOENT; + + rcu_read_lock(); + memcg_css = css_from_id(memcg_id, &memory_cgrp_subsys); + if (memcg_css && !css_tryget(memcg_css)) + memcg_css = NULL; + rcu_read_unlock(); + if (!memcg_css) { + ret = -ENOENT; + goto out_bdi_put; + } + + /* + * And find the associated wb. If the wb isn't there already + * there's nothing to flush, don't create one. + */ + wb = wb_get_lookup(bdi, memcg_css); + if (!wb) { + ret = -ENOENT; + goto out_css_put; + } + + /* issue the writeback work */ + work = kzalloc(sizeof(*work), GFP_NOWAIT | __GFP_NOWARN); + if (work) { + work->nr_pages = nr; + work->sync_mode = WB_SYNC_NONE; + work->reason = reason; + work->done = done; + work->auto_free = 1; + wb_queue_work(wb, work); + ret = 0; + } else { + ret = -ENOMEM; + } + + wb_put(wb); +out_css_put: + css_put(memcg_css); +out_bdi_put: + bdi_put(bdi); + return ret; +} + +/** * cgroup_writeback_umount - flush inode wb switches for umount * * This function is called when a super_block is about to be destroyed and --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -217,6 +217,8 @@ void wbc_attach_and_unlock_inode(struct void wbc_detach_inode(struct writeback_control *wbc); void wbc_account_cgroup_owner(struct writeback_control *wbc, struct page *page, size_t bytes); +int cgroup_writeback_by_id(u64 bdi_id, int memcg_id, unsigned long nr_pages, + enum wb_reason reason, struct wb_completion *done); void cgroup_writeback_umount(void); /**
Implement cgroup_writeback_by_id() which initiates cgroup writeback from bdi and memcg IDs. This will be used by memcg foreign inode flushing. Signed-off-by: Tejun Heo <tj@kernel.org> --- fs/fs-writeback.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/writeback.h | 2 + 2 files changed, 69 insertions(+)