On Fri, 5 Mar 2010 10:12:34 +0900 Daisuke Nishimura <[email protected]> wrote:
> On Thu, 4 Mar 2010 11:40:14 +0100, Andrea Righi <[email protected]> wrote: > > Infrastructure to account dirty pages per cgroup and add dirty limit > > static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data) > > { > > int *val = data; > > @@ -1275,34 +1423,70 @@ static void record_last_oom(struct mem_cgroup *mem) > > } > > > > /* > > - * Currently used to update mapped file statistics, but the routine can be > > - * generalized to update other statistics as well. > > + * Generalized routine to update file cache's status for memcg. > > + * > > + * Before calling this, mapping->tree_lock should be held and preemption is > > + * disabled. Then, it's guarnteed that the page is not uncharged while we > > + * access page_cgroup. We can make use of that. > > */ > IIUC, mapping->tree_lock is held with irq disabled, so I think > "mapping->tree_lock > should be held with irq disabled" would be enouth. > And, as far as I can see, callers of this function have not ensured this yet > in [4/4]. > > how about: > > void mem_cgroup_update_stat_locked(...) > { > ... > } > > void mem_cgroup_update_stat_unlocked(mapping, ...) > { > spin_lock_irqsave(mapping->tree_lock, ...); > mem_cgroup_update_stat_locked(); > spin_unlock_irqrestore(...); > } > Rather than tree_lock, lock_page_cgroup() can be used if tree_lock is not held. lock_page_cgroup(); mem_cgroup_update_stat_locked(); unlock_page_cgroup(); Andrea-san, FILE_MAPPED is updated without treelock, at least. You can't depend on migration_lock about FILE_MAPPED. > > -void mem_cgroup_update_file_mapped(struct page *page, int val) > > +void mem_cgroup_update_stat(struct page *page, > > + enum mem_cgroup_stat_index idx, int val) > > { > I preffer "void mem_cgroup_update_page_stat(struct page *, enum > mem_cgroup_page_stat_item, ..)" > as I said above. > > > struct mem_cgroup *mem; > > struct page_cgroup *pc; > > > > + if (mem_cgroup_disabled()) > > + return; > > pc = lookup_page_cgroup(page); > > - if (unlikely(!pc)) > > + if (unlikely(!pc) || !PageCgroupUsed(pc)) > > return; > > > > - lock_page_cgroup(pc); > > - mem = pc->mem_cgroup; > > - if (!mem) > > - goto done; > > - > > - if (!PageCgroupUsed(pc)) > > - goto done; > > - > > + lock_page_cgroup_migrate(pc); > > /* > > - * Preemption is already disabled. We can use __this_cpu_xxx > > - */ > > - __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], val); > > - > > -done: > > - unlock_page_cgroup(pc); > > + * It's guarnteed that this page is never uncharged. > > + * The only racy problem is moving account among memcgs. > > + */ > > + switch (idx) { > > + case MEM_CGROUP_STAT_FILE_MAPPED: > > + if (val > 0) > > + SetPageCgroupFileMapped(pc); > > + else > > + ClearPageCgroupFileMapped(pc); > > + break; > > + case MEM_CGROUP_STAT_FILE_DIRTY: > > + if (val > 0) > > + SetPageCgroupDirty(pc); > > + else > > + ClearPageCgroupDirty(pc); > > + break; > > + case MEM_CGROUP_STAT_WRITEBACK: > > + if (val > 0) > > + SetPageCgroupWriteback(pc); > > + else > > + ClearPageCgroupWriteback(pc); > > + break; > > + case MEM_CGROUP_STAT_WRITEBACK_TEMP: > > + if (val > 0) > > + SetPageCgroupWritebackTemp(pc); > > + else > > + ClearPageCgroupWritebackTemp(pc); > > + break; > > + case MEM_CGROUP_STAT_UNSTABLE_NFS: > > + if (val > 0) > > + SetPageCgroupUnstableNFS(pc); > > + else > > + ClearPageCgroupUnstableNFS(pc); > > + break; > > + default: > > + BUG(); > > + break; > > + } > > + mem = pc->mem_cgroup; > > + if (likely(mem)) > > + __this_cpu_add(mem->stat->count[idx], val); > > + unlock_page_cgroup_migrate(pc); > > } > > +EXPORT_SYMBOL_GPL(mem_cgroup_update_stat); > > > > /* > > * size of first charge trial. "32" comes from vmscan.c's magic value. > > @@ -1701,6 +1885,45 @@ static void __mem_cgroup_commit_charge(struct > > mem_cgroup *mem, > > memcg_check_events(mem, pc->page); > > } > > > > +/* > > + * Update file cache accounted statistics on task migration. > > + * > > + * TODO: We don't move charges of file (including shmem/tmpfs) pages for > > now. > > + * So, at the moment this function simply returns without updating > > accounted > > + * statistics, because we deal only with anonymous pages here. > > + */ > This function is not unique to task migration. It's called from rmdir() too. > So this comment isn't needed. > > > +static void __mem_cgroup_update_file_stat(struct page_cgroup *pc, > > + struct mem_cgroup *from, struct mem_cgroup *to) > > +{ > > + struct page *page = pc->page; > > + > > + if (!page_mapped(page) || PageAnon(page)) > > + return; > > + > > + if (PageCgroupFileMapped(pc)) { > > + __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); > > + __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); > > + } > > + if (PageCgroupDirty(pc)) { > > + __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_DIRTY]); > > + __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_DIRTY]); > > + } > > + if (PageCgroupWriteback(pc)) { > > + __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_WRITEBACK]); > > + __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_WRITEBACK]); > > + } > > + if (PageCgroupWritebackTemp(pc)) { > > + __this_cpu_dec( > > + from->stat->count[MEM_CGROUP_STAT_WRITEBACK_TEMP]); > > + __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_WRITEBACK_TEMP]); > > + } > > + if (PageCgroupUnstableNFS(pc)) { > > + __this_cpu_dec( > > + from->stat->count[MEM_CGROUP_STAT_UNSTABLE_NFS]); > > + __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_UNSTABLE_NFS]); > > + } > > +} > > + > > /** > > * __mem_cgroup_move_account - move account of the page > > * @pc: page_cgroup of the page. > > @@ -1721,22 +1944,16 @@ static void __mem_cgroup_commit_charge(struct > > mem_cgroup *mem, > > static void __mem_cgroup_move_account(struct page_cgroup *pc, > > struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge) > > { > > - struct page *page; > > - > > VM_BUG_ON(from == to); > > VM_BUG_ON(PageLRU(pc->page)); > > VM_BUG_ON(!PageCgroupLocked(pc)); > > VM_BUG_ON(!PageCgroupUsed(pc)); > > VM_BUG_ON(pc->mem_cgroup != from); > > > > - page = pc->page; > > - if (page_mapped(page) && !PageAnon(page)) { > > - /* Update mapped_file data for mem_cgroup */ > > - preempt_disable(); > > - __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); > > - __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); > > - preempt_enable(); > > - } > > + preempt_disable(); > > + lock_page_cgroup_migrate(pc); > > + __mem_cgroup_update_file_stat(pc, from, to); > > + > > mem_cgroup_charge_statistics(from, pc, false); > > if (uncharge) > > /* This is not "cancel", but cancel_charge does all we need. */ > > @@ -1745,6 +1962,8 @@ static void __mem_cgroup_move_account(struct > > page_cgroup *pc, > > /* caller should have done css_get */ > > pc->mem_cgroup = to; > > mem_cgroup_charge_statistics(to, pc, true); > > + unlock_page_cgroup_migrate(pc); > > + preempt_enable(); > Glad to see this cleanup :) > But, hmm, I don't think preempt_disable/enable() is enough(and > bit_spin_lock/unlock() > does it anyway). lock/unlock_page_cgroup_migrate() can be called under irq > context > (e.g. end_page_writeback()), so I think we must local_irq_disable()/enable() > here. > Ah, hmm, yes. irq-disable is required. Thanks, -Kame > _______________________________________________ Containers mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/containers _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
