| Message ID | 20171009212911.473208-3-tj@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon 09-10-17 14:29:10, Tejun Heo wrote: > Add wbc->blkcg_css so that the blkcg_css association can be specified > independently and implement submit_bh_blkcg_css() using it. This will > be used to override cgroup membership on specific buffer_heads. > > Signed-off-by: Tejun Heo <tj@kernel.org> > Cc: Jan Kara <jack@suse.cz> > Cc: Jens Axboe <axboe@kernel.dk> Hum, I dislike growing wbc just to pass blkcg_css through one function in fs/buffer.c (in otherwise empty wbc). Not that space would be a big concern for wbc but it just gets messier... Cannot we just refactor the code a bit like: 1) Create function struct bio *create_bio_bh(int op, int op_flags, struct buffer_head *bh, enum rw_hint write_hint); which would create bio from bh. 2) Make submit_bh(), submit_bh_wbc(), submit_bh_blkcg_css() use this and the latter two would further tweak the bio as needed before submitting. Thoughts? Honza > --- > fs/buffer.c | 12 ++++++++++++ > fs/fs-writeback.c | 1 + > include/linux/buffer_head.h | 11 +++++++++++ > include/linux/writeback.h | 6 ++++-- > 4 files changed, 28 insertions(+), 2 deletions(-) > > diff --git a/fs/buffer.c b/fs/buffer.c > index 170df85..fac4f9a 100644 > --- a/fs/buffer.c > +++ b/fs/buffer.c > @@ -3143,6 +3143,18 @@ int submit_bh(int op, int op_flags, struct buffer_head *bh) > } > EXPORT_SYMBOL(submit_bh); > > +#ifdef CONFIG_CGROUP_WRITEBACK > +int submit_bh_blkcg_css(int op, int op_flags, struct buffer_head *bh, > + struct cgroup_subsys_state *blkcg_css) > +{ > + struct writeback_control wbc = { .blkcg_css = blkcg_css }; > + > + /* @wbc is used just to override the bio's blkcg_css */ > + return submit_bh_wbc(op, op_flags, bh, 0, &wbc); > +} > +EXPORT_SYMBOL(submit_bh_blkcg_css); > +#endif > + > /** > * ll_rw_block: low-level access to block devices (DEPRECATED) > * @op: whether to %READ or %WRITE > diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c > index 245c430..cd882e6 100644 > --- a/fs/fs-writeback.c > +++ b/fs/fs-writeback.c > @@ -538,6 +538,7 @@ void wbc_attach_and_unlock_inode(struct writeback_control *wbc, > } > > wbc->wb = inode_to_wb(inode); > + wbc->blkcg_css = wbc->wb->blkcg_css; > wbc->inode = inode; > > wbc->wb_id = wbc->wb->memcg_css->id; > diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h > index c8dae55..abb4dd4 100644 > --- a/include/linux/buffer_head.h > +++ b/include/linux/buffer_head.h > @@ -13,6 +13,7 @@ > #include <linux/pagemap.h> > #include <linux/wait.h> > #include <linux/atomic.h> > +#include <linux/cgroup.h> > > #ifdef CONFIG_BLOCK > > @@ -205,6 +206,16 @@ int bh_submit_read(struct buffer_head *bh); > loff_t page_cache_seek_hole_data(struct inode *inode, loff_t offset, > loff_t length, int whence); > > +#ifdef CONFIG_CGROUP_WRITEBACK > +int submit_bh_blkcg(int op, int op_flags, struct buffer_head *bh, > + struct cgroup_subsys_state *blkcg_css); > +#else > +static inline int submit_bh_blkcg(int op, int op_flags, struct buffer_head *bh, > + struct cgroup_subsys_state *blkcg_css) > +{ > + return submit_bh(op, op_flags, bh); > +} > +#endif > extern int buffer_heads_over_limit; > > /* > diff --git a/include/linux/writeback.h b/include/linux/writeback.h > index d581579..81e5946 100644 > --- a/include/linux/writeback.h > +++ b/include/linux/writeback.h > @@ -91,6 +91,8 @@ struct writeback_control { > unsigned for_sync:1; /* sync(2) WB_SYNC_ALL writeback */ > #ifdef CONFIG_CGROUP_WRITEBACK > struct bdi_writeback *wb; /* wb this writeback is issued under */ > + struct cgroup_subsys_state *blkcg_css; /* usually wb->blkcg_css but > + may be overridden */ > struct inode *inode; /* inode being written out */ > > /* foreign inode detection, see wbc_detach_inode() */ > @@ -277,8 +279,8 @@ static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio) > * behind a slow cgroup. Ultimately, we want pageout() to kick off > * regular writeback instead of writing things out itself. > */ > - if (wbc->wb) > - bio_associate_blkcg(bio, wbc->wb->blkcg_css); > + if (wbc->blkcg_css) > + bio_associate_blkcg(bio, wbc->blkcg_css); > } > > #else /* CONFIG_CGROUP_WRITEBACK */ > -- > 2.9.5 >
diff --git a/fs/buffer.c b/fs/buffer.c index 170df85..fac4f9a 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -3143,6 +3143,18 @@ int submit_bh(int op, int op_flags, struct buffer_head *bh) } EXPORT_SYMBOL(submit_bh); +#ifdef CONFIG_CGROUP_WRITEBACK +int submit_bh_blkcg_css(int op, int op_flags, struct buffer_head *bh, + struct cgroup_subsys_state *blkcg_css) +{ + struct writeback_control wbc = { .blkcg_css = blkcg_css }; + + /* @wbc is used just to override the bio's blkcg_css */ + return submit_bh_wbc(op, op_flags, bh, 0, &wbc); +} +EXPORT_SYMBOL(submit_bh_blkcg_css); +#endif + /** * ll_rw_block: low-level access to block devices (DEPRECATED) * @op: whether to %READ or %WRITE diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 245c430..cd882e6 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -538,6 +538,7 @@ void wbc_attach_and_unlock_inode(struct writeback_control *wbc, } wbc->wb = inode_to_wb(inode); + wbc->blkcg_css = wbc->wb->blkcg_css; wbc->inode = inode; wbc->wb_id = wbc->wb->memcg_css->id; diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index c8dae55..abb4dd4 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -13,6 +13,7 @@ #include <linux/pagemap.h> #include <linux/wait.h> #include <linux/atomic.h> +#include <linux/cgroup.h> #ifdef CONFIG_BLOCK @@ -205,6 +206,16 @@ int bh_submit_read(struct buffer_head *bh); loff_t page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length, int whence); +#ifdef CONFIG_CGROUP_WRITEBACK +int submit_bh_blkcg(int op, int op_flags, struct buffer_head *bh, + struct cgroup_subsys_state *blkcg_css); +#else +static inline int submit_bh_blkcg(int op, int op_flags, struct buffer_head *bh, + struct cgroup_subsys_state *blkcg_css) +{ + return submit_bh(op, op_flags, bh); +} +#endif extern int buffer_heads_over_limit; /* diff --git a/include/linux/writeback.h b/include/linux/writeback.h index d581579..81e5946 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -91,6 +91,8 @@ struct writeback_control { unsigned for_sync:1; /* sync(2) WB_SYNC_ALL writeback */ #ifdef CONFIG_CGROUP_WRITEBACK struct bdi_writeback *wb; /* wb this writeback is issued under */ + struct cgroup_subsys_state *blkcg_css; /* usually wb->blkcg_css but + may be overridden */ struct inode *inode; /* inode being written out */ /* foreign inode detection, see wbc_detach_inode() */ @@ -277,8 +279,8 @@ static inline void wbc_init_bio(struct writeback_control *wbc, struct bio *bio) * behind a slow cgroup. Ultimately, we want pageout() to kick off * regular writeback instead of writing things out itself. */ - if (wbc->wb) - bio_associate_blkcg(bio, wbc->wb->blkcg_css); + if (wbc->blkcg_css) + bio_associate_blkcg(bio, wbc->blkcg_css); } #else /* CONFIG_CGROUP_WRITEBACK */
Add wbc->blkcg_css so that the blkcg_css association can be specified independently and implement submit_bh_blkcg_css() using it. This will be used to override cgroup membership on specific buffer_heads. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> --- fs/buffer.c | 12 ++++++++++++ fs/fs-writeback.c | 1 + include/linux/buffer_head.h | 11 +++++++++++ include/linux/writeback.h | 6 ++++-- 4 files changed, 28 insertions(+), 2 deletions(-)