| Message ID | 20200824153607.6595-3-schatzberg.dan@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Charge loop device i/o to issuing cgroup | expand |
On Mon, Aug 24, 2020 at 11:36:00AM -0400, Dan Schatzberg wrote: > From: Johannes Weiner <hannes@cmpxchg.org> > > 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: Johannes Weiner <hannes@cmpxchg.org> > Reviewed-by: Shakeel Butt <shakeelb@google.com> > Acked-by: Roman Gushchin <guro@fb.com> > Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Hi Dan, JFYI: I need a similar patch for the bpf memory accounting rework, so I ended up sending it separately (with some modifications including different naming): https://lkml.org/lkml/2020/8/21/1464 . Can you please, rebase your patchset using this patch? I hope Andrew can pull this standalone patch into 5.9-rc*, as Shakeel suggested. It will help us to avoid merge conflicts during the 5.10 merge window. Thanks!
On Mon, Aug 24, 2020 at 09:19:01AM -0700, Roman Gushchin wrote: > Hi Dan, > > JFYI: I need a similar patch for the bpf memory accounting rework, > so I ended up sending it separately (with some modifications including > different naming): https://lkml.org/lkml/2020/8/21/1464 . > > Can you please, rebase your patchset using this patch? > > I hope Andrew can pull this standalone patch into 5.9-rc*, > as Shakeel suggested. It will help us to avoid merge conflicts > during the 5.10 merge window. > > Thanks! Yeah I mentioned it in the cover letter and linked to your patch. I had not realized the naming change, so I can rebase on top of that - I'll wait to see if there's other feedback first.
diff --git a/fs/buffer.c b/fs/buffer.c index d468ed9981e0..804170cb59fe 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -842,13 +842,13 @@ 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, *old_memcg; if (retry) gfp |= __GFP_NOFAIL; memcg = get_mem_cgroup_from_page(page); - memalloc_use_memcg(memcg); + old_memcg = memalloc_use_memcg(memcg); head = NULL; offset = PAGE_SIZE; @@ -867,7 +867,7 @@ 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(old_memcg); mem_cgroup_put(memcg); return head; /* diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index c942910a8649..c8fd563e02a3 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -533,6 +533,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS); struct inode *child = NULL; bool name_event = false; + struct mem_cgroup *old_memcg; if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) { /* @@ -580,7 +581,7 @@ static 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); + old_memcg = memalloc_use_memcg(group->memcg); if (fanotify_is_perm_event(mask)) { event = fanotify_alloc_perm_event(path, gfp); @@ -608,7 +609,7 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, event->pid = get_pid(task_tgid(current)); out: - memalloc_unuse_memcg(); + memalloc_use_memcg(old_memcg); return event; } diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index a65cf8c9f600..8017a51561c4 100644 --- a/fs/notify/inotify/inotify_fsnotify.c +++ b/fs/notify/inotify/inotify_fsnotify.c @@ -66,6 +66,7 @@ static int inotify_one_event(struct fsnotify_group *group, u32 mask, int ret; int len = 0; int alloc_len = sizeof(struct inotify_event_info); + struct mem_cgroup *old_memcg; if ((inode_mark->mask & FS_EXCL_UNLINK) && path && d_unlinked(path->dentry)) @@ -87,9 +88,9 @@ static int inotify_one_event(struct fsnotify_group *group, u32 mask, * trigger OOM killer in the target monitoring memcg as it may have * security repercussion. */ - memalloc_use_memcg(group->memcg); + old_memcg = memalloc_use_memcg(group->memcg); event = kmalloc(alloc_len, GFP_KERNEL_ACCOUNT | __GFP_RETRY_MAYFAIL); - memalloc_unuse_memcg(); + memalloc_use_memcg(old_memcg); if (unlikely(!event)) { /* diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h index f889e332912f..b8fde48d44a9 100644 --- a/include/linux/sched/mm.h +++ b/include/linux/sched/mm.h @@ -312,31 +312,21 @@ 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 diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b807952b4d43..b2468c80085d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5271,12 +5271,12 @@ static struct cgroup_subsys_state * __ref mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) { struct mem_cgroup *parent = mem_cgroup_from_css(parent_css); - struct mem_cgroup *memcg; + struct mem_cgroup *memcg, *old_memcg; long error = -ENOMEM; - memalloc_use_memcg(parent); + old_memcg = memalloc_use_memcg(parent); memcg = mem_cgroup_alloc(); - memalloc_unuse_memcg(); + memalloc_use_memcg(old_memcg); if (IS_ERR(memcg)) return ERR_CAST(memcg);