| Message ID | 20200420223936.6773-3-schatzberg.dan@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Charge loop device i/o to issuing cgroup | expand |
On Mon, Apr 20, 2020 at 3:41 PM Dan Schatzberg <schatzberg.dan@gmail.com> wrote: > > The memalloc_use_memcg() function to override the default memcg > accounting context currently doesn't nest. But the patches to make the > loop driver cgroup-aware will end up nesting: > > [ 98.137605] alloc_page_buffers+0x210/0x288 > [ 98.141799] __getblk_gfp+0x1d4/0x400 > [ 98.145475] ext4_read_block_bitmap_nowait+0x148/0xbc8 > [ 98.150628] ext4_mb_init_cache+0x25c/0x9b0 > [ 98.154821] ext4_mb_init_group+0x270/0x390 > [ 98.159014] ext4_mb_good_group+0x264/0x270 > [ 98.163208] ext4_mb_regular_allocator+0x480/0x798 > [ 98.168011] ext4_mb_new_blocks+0x958/0x10f8 > [ 98.172294] ext4_ext_map_blocks+0xec8/0x1618 > [ 98.176660] ext4_map_blocks+0x1b8/0x8a0 > [ 98.180592] ext4_writepages+0x830/0xf10 > [ 98.184523] do_writepages+0xb4/0x198 > [ 98.188195] __filemap_fdatawrite_range+0x170/0x1c8 > [ 98.193086] filemap_write_and_wait_range+0x40/0xb0 > [ 98.197974] ext4_punch_hole+0x4a4/0x660 > [ 98.201907] ext4_fallocate+0x294/0x1190 > [ 98.205839] loop_process_work+0x690/0x1100 > [ 98.210032] loop_workfn+0x2c/0x110 > [ 98.213529] process_one_work+0x3e0/0x648 > [ 98.217546] worker_thread+0x70/0x670 > [ 98.221217] kthread+0x1b8/0x1c0 > [ 98.224452] ret_from_fork+0x10/0x18 > > where loop_process_work() sets the memcg override to the memcg that > submitted the IO request, and alloc_page_buffers() sets the override > to the memcg that instantiated the cache page, which may differ. > > Make memalloc_use_memcg() return the old memcg and convert existing > users to a stacking model. Delete the unused memalloc_unuse_memcg(). > > Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com> This patch was from Johannes, so I would suggest to keep his authorship and signoff along with your signoff. Reviewed-by: Shakeel Butt <shakeelb@google.com>
On Mon, Apr 20, 2020 at 06:39:30PM -0400, Dan Schatzberg wrote: > The memalloc_use_memcg() function to override the default memcg > accounting context currently doesn't nest. But the patches to make the > loop driver cgroup-aware will end up nesting: > > [ 98.137605] alloc_page_buffers+0x210/0x288 > [ 98.141799] __getblk_gfp+0x1d4/0x400 > [ 98.145475] ext4_read_block_bitmap_nowait+0x148/0xbc8 > [ 98.150628] ext4_mb_init_cache+0x25c/0x9b0 > [ 98.154821] ext4_mb_init_group+0x270/0x390 > [ 98.159014] ext4_mb_good_group+0x264/0x270 > [ 98.163208] ext4_mb_regular_allocator+0x480/0x798 > [ 98.168011] ext4_mb_new_blocks+0x958/0x10f8 > [ 98.172294] ext4_ext_map_blocks+0xec8/0x1618 > [ 98.176660] ext4_map_blocks+0x1b8/0x8a0 > [ 98.180592] ext4_writepages+0x830/0xf10 > [ 98.184523] do_writepages+0xb4/0x198 > [ 98.188195] __filemap_fdatawrite_range+0x170/0x1c8 > [ 98.193086] filemap_write_and_wait_range+0x40/0xb0 > [ 98.197974] ext4_punch_hole+0x4a4/0x660 > [ 98.201907] ext4_fallocate+0x294/0x1190 > [ 98.205839] loop_process_work+0x690/0x1100 > [ 98.210032] loop_workfn+0x2c/0x110 > [ 98.213529] process_one_work+0x3e0/0x648 > [ 98.217546] worker_thread+0x70/0x670 > [ 98.221217] kthread+0x1b8/0x1c0 > [ 98.224452] ret_from_fork+0x10/0x18 > > where loop_process_work() sets the memcg override to the memcg that > submitted the IO request, and alloc_page_buffers() sets the override > to the memcg that instantiated the cache page, which may differ. > > Make memalloc_use_memcg() return the old memcg and convert existing > users to a stacking model. Delete the unused memalloc_unuse_memcg(). > > Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com> Acked-by: Roman Gushchin <guro@fb.com> One small nit below. Thanks! > --- > fs/buffer.c | 6 +++--- > fs/notify/fanotify/fanotify.c | 5 +++-- > fs/notify/inotify/inotify_fsnotify.c | 5 +++-- > include/linux/sched/mm.h | 28 +++++++++------------------- > 4 files changed, 18 insertions(+), 26 deletions(-) > > diff --git a/fs/buffer.c b/fs/buffer.c > index 599a0bf7257b..e39e05985323 100644 > --- a/fs/buffer.c > +++ b/fs/buffer.c > @@ -851,13 +851,13 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, > struct buffer_head *bh, *head; > gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT; > long offset; > - struct mem_cgroup *memcg; > + struct mem_cgroup *memcg, *oldmemcg; I'd rename it to old_memcg. > > if (retry) > gfp |= __GFP_NOFAIL; > > memcg = get_mem_cgroup_from_page(page); > - memalloc_use_memcg(memcg); > + oldmemcg = memalloc_use_memcg(memcg); > > head = NULL; > offset = PAGE_SIZE; > @@ -876,7 +876,7 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, > set_bh_page(bh, page, offset); > } > out: > - memalloc_unuse_memcg(); > + memalloc_use_memcg(oldmemcg); > mem_cgroup_put(memcg); > return head; > /* > diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c > index 5435a40f82be..54c787cd6efb 100644 > --- a/fs/notify/fanotify/fanotify.c > +++ b/fs/notify/fanotify/fanotify.c > @@ -353,6 +353,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, > gfp_t gfp = GFP_KERNEL_ACCOUNT; > struct inode *id = fanotify_fid_inode(inode, mask, data, data_type); > const struct path *path = fsnotify_data_path(data, data_type); > + struct mem_cgroup *oldmemcg; > > /* > * For queues with unlimited length lost events are not expected and > @@ -366,7 +367,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, > gfp |= __GFP_RETRY_MAYFAIL; > > /* Whoever is interested in the event, pays for the allocation. */ > - memalloc_use_memcg(group->memcg); > + oldmemcg = memalloc_use_memcg(group->memcg); > > if (fanotify_is_perm_event(mask)) { > struct fanotify_perm_event *pevent; > @@ -451,7 +452,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, > } > } > out: > - memalloc_unuse_memcg(); > + memalloc_use_memcg(oldmemcg); > return event; > } > > diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c > index 2ebc89047153..d27c6e83cea6 100644 > --- a/fs/notify/inotify/inotify_fsnotify.c > +++ b/fs/notify/inotify/inotify_fsnotify.c > @@ -69,6 +69,7 @@ int inotify_handle_event(struct fsnotify_group *group, > int ret; > int len = 0; > int alloc_len = sizeof(struct inotify_event_info); > + struct mem_cgroup *oldmemcg; > > if (WARN_ON(fsnotify_iter_vfsmount_mark(iter_info))) > return 0; > @@ -93,9 +94,9 @@ int inotify_handle_event(struct fsnotify_group *group, > * trigger OOM killer in the target monitoring memcg as it may have > * security repercussion. > */ > - memalloc_use_memcg(group->memcg); > + oldmemcg = memalloc_use_memcg(group->memcg); > event = kmalloc(alloc_len, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL); > - memalloc_unuse_memcg(); > + memalloc_use_memcg(oldmemcg); > > if (unlikely(!event)) { > /* > diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h > index c49257a3b510..95e8bfb0cab1 100644 > --- a/include/linux/sched/mm.h > +++ b/include/linux/sched/mm.h > @@ -316,31 +316,21 @@ static inline void memalloc_nocma_restore(unsigned int flags) > * __GFP_ACCOUNT allocations till the end of the scope will be charged to the > * given memcg. > * > - * NOTE: This function is not nesting safe. > + * NOTE: This function can nest. Users must save the return value and > + * reset the previous value after their own charging scope is over > */ > -static inline void memalloc_use_memcg(struct mem_cgroup *memcg) > +static inline struct mem_cgroup * > +memalloc_use_memcg(struct mem_cgroup *memcg) > { > - WARN_ON_ONCE(current->active_memcg); > + struct mem_cgroup *old = current->active_memcg; > current->active_memcg = memcg; > -} > - > -/** > - * memalloc_unuse_memcg - Ends the remote memcg charging scope. > - * > - * This function marks the end of the remote memcg charging scope started by > - * memalloc_use_memcg(). > - */ > -static inline void memalloc_unuse_memcg(void) > -{ > - current->active_memcg = NULL; > + return old; > } > #else > -static inline void memalloc_use_memcg(struct mem_cgroup *memcg) > -{ > -} > - > -static inline void memalloc_unuse_memcg(void) > +static inline struct mem_cgroup * > +memalloc_use_memcg(struct mem_cgroup *memcg) > { > + return NULL; > } > #endif > > -- > 2.24.1 >
diff --git a/fs/buffer.c b/fs/buffer.c index 599a0bf7257b..e39e05985323 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -851,13 +851,13 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, struct buffer_head *bh, *head; gfp_t gfp = GFP_NOFS | __GFP_ACCOUNT; long offset; - struct mem_cgroup *memcg; + struct mem_cgroup *memcg, *oldmemcg; if (retry) gfp |= __GFP_NOFAIL; memcg = get_mem_cgroup_from_page(page); - memalloc_use_memcg(memcg); + oldmemcg = memalloc_use_memcg(memcg); head = NULL; offset = PAGE_SIZE; @@ -876,7 +876,7 @@ struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size, set_bh_page(bh, page, offset); } out: - memalloc_unuse_memcg(); + memalloc_use_memcg(oldmemcg); mem_cgroup_put(memcg); return head; /* diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 5435a40f82be..54c787cd6efb 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -353,6 +353,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, gfp_t gfp = GFP_KERNEL_ACCOUNT; struct inode *id = fanotify_fid_inode(inode, mask, data, data_type); const struct path *path = fsnotify_data_path(data, data_type); + struct mem_cgroup *oldmemcg; /* * For queues with unlimited length lost events are not expected and @@ -366,7 +367,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, gfp |= __GFP_RETRY_MAYFAIL; /* Whoever is interested in the event, pays for the allocation. */ - memalloc_use_memcg(group->memcg); + oldmemcg = memalloc_use_memcg(group->memcg); if (fanotify_is_perm_event(mask)) { struct fanotify_perm_event *pevent; @@ -451,7 +452,7 @@ struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, } } out: - memalloc_unuse_memcg(); + memalloc_use_memcg(oldmemcg); return event; } diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index 2ebc89047153..d27c6e83cea6 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -69,6 +69,7 @@ int inotify_handle_event(struct fsnotify_group *group, int ret; int len = 0; int alloc_len = sizeof(struct inotify_event_info); + struct mem_cgroup *oldmemcg; if (WARN_ON(fsnotify_iter_vfsmount_mark(iter_info))) return 0; @@ -93,9 +94,9 @@ int inotify_handle_event(struct fsnotify_group *group, * trigger OOM killer in the target monitoring memcg as it may have * security repercussion. */ - memalloc_use_memcg(group->memcg); + oldmemcg = memalloc_use_memcg(group->memcg); event = kmalloc(alloc_len, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL); - memalloc_unuse_memcg(); + memalloc_use_memcg(oldmemcg); if (unlikely(!event)) { /* diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index c49257a3b510..95e8bfb0cab1 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -316,31 +316,21 @@ static inline void memalloc_nocma_restore(unsigned int flags) * __GFP_ACCOUNT allocations till the end of the scope will be charged to the * given memcg. * - * NOTE: This function is not nesting safe. + * NOTE: This function can nest. Users must save the return value and + * reset the previous value after their own charging scope is over */ -static inline void memalloc_use_memcg(struct mem_cgroup *memcg) +static inline struct mem_cgroup * +memalloc_use_memcg(struct mem_cgroup *memcg) { - WARN_ON_ONCE(current->active_memcg); + struct mem_cgroup *old = current->active_memcg; current->active_memcg = memcg; -} - -/** - * memalloc_unuse_memcg - Ends the remote memcg charging scope. - * - * This function marks the end of the remote memcg charging scope started by - * memalloc_use_memcg(). - */ -static inline void memalloc_unuse_memcg(void) -{ - current->active_memcg = NULL; + return old; } #else -static inline void memalloc_use_memcg(struct mem_cgroup *memcg) -{ -} - -static inline void memalloc_unuse_memcg(void) +static inline struct mem_cgroup * +memalloc_use_memcg(struct mem_cgroup *memcg) { + return NULL; } #endif
The memalloc_use_memcg() function to override the default memcg accounting context currently doesn't nest. But the patches to make the loop driver cgroup-aware will end up nesting: [ 98.137605] alloc_page_buffers+0x210/0x288 [ 98.141799] __getblk_gfp+0x1d4/0x400 [ 98.145475] ext4_read_block_bitmap_nowait+0x148/0xbc8 [ 98.150628] ext4_mb_init_cache+0x25c/0x9b0 [ 98.154821] ext4_mb_init_group+0x270/0x390 [ 98.159014] ext4_mb_good_group+0x264/0x270 [ 98.163208] ext4_mb_regular_allocator+0x480/0x798 [ 98.168011] ext4_mb_new_blocks+0x958/0x10f8 [ 98.172294] ext4_ext_map_blocks+0xec8/0x1618 [ 98.176660] ext4_map_blocks+0x1b8/0x8a0 [ 98.180592] ext4_writepages+0x830/0xf10 [ 98.184523] do_writepages+0xb4/0x198 [ 98.188195] __filemap_fdatawrite_range+0x170/0x1c8 [ 98.193086] filemap_write_and_wait_range+0x40/0xb0 [ 98.197974] ext4_punch_hole+0x4a4/0x660 [ 98.201907] ext4_fallocate+0x294/0x1190 [ 98.205839] loop_process_work+0x690/0x1100 [ 98.210032] loop_workfn+0x2c/0x110 [ 98.213529] process_one_work+0x3e0/0x648 [ 98.217546] worker_thread+0x70/0x670 [ 98.221217] kthread+0x1b8/0x1c0 [ 98.224452] ret_from_fork+0x10/0x18 where loop_process_work() sets the memcg override to the memcg that submitted the IO request, and alloc_page_buffers() sets the override to the memcg that instantiated the cache page, which may differ. Make memalloc_use_memcg() return the old memcg and convert existing users to a stacking model. Delete the unused memalloc_unuse_memcg(). Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com> --- fs/buffer.c | 6 +++--- fs/notify/fanotify/fanotify.c | 5 +++-- fs/notify/inotify/inotify_fsnotify.c | 5 +++-- include/linux/sched/mm.h | 28 +++++++++------------------- 4 files changed, 18 insertions(+), 26 deletions(-)