From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752422Ab0CBKE6 (ORCPT ); Tue, 2 Mar 2010 05:04:58 -0500 Received: from mail-ww0-f46.google.com ([74.125.82.46]:58395 "EHLO mail-ww0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752360Ab0CBKE4 convert rfc822-to-8bit (ORCPT ); Tue, 2 Mar 2010 05:04:56 -0500 MIME-Version: 1.0 In-Reply-To: <1267478620-5276-3-git-send-email-arighi@develer.com> References: <1267478620-5276-1-git-send-email-arighi@develer.com> <1267478620-5276-3-git-send-email-arighi@develer.com> Date: Tue, 2 Mar 2010 12:04:53 +0200 Message-ID: Subject: Re: [PATCH -mmotm 2/3] memcg: dirty pages accounting and limiting infrastructure From: "Kirill A. Shutemov" To: Andrea Righi Cc: Balbir Singh , KAMEZAWA Hiroyuki , Suleiman Souhlal , Greg Thelen , Daisuke Nishimura , Andrew Morton , containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 1, 2010 at 11:23 PM, Andrea Righi wrote: > Infrastructure to account dirty pages per cgroup and add dirty limit > interfaces in the cgroupfs: > >  - Direct write-out: memory.dirty_ratio, memory.dirty_bytes > >  - Background write-out: memory.dirty_background_ratio, memory.dirty_background_bytes > > Signed-off-by: Andrea Righi > --- >  include/linux/memcontrol.h |   77 ++++++++++- >  mm/memcontrol.c            |  336 ++++++++++++++++++++++++++++++++++++++++---- >  2 files changed, 384 insertions(+), 29 deletions(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 1f9b119..cc88b2e 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -19,12 +19,50 @@ > >  #ifndef _LINUX_MEMCONTROL_H >  #define _LINUX_MEMCONTROL_H > + > +#include >  #include > + >  struct mem_cgroup; >  struct page_cgroup; >  struct page; >  struct mm_struct; > > +/* Cgroup memory statistics items exported to the kernel */ > +enum mem_cgroup_page_stat_item { > +       MEMCG_NR_DIRTYABLE_PAGES, > +       MEMCG_NR_RECLAIM_PAGES, > +       MEMCG_NR_WRITEBACK, > +       MEMCG_NR_DIRTY_WRITEBACK_PAGES, > +}; > + > +/* > + * Statistics for memory cgroup. > + */ > +enum mem_cgroup_stat_index { > +       /* > +        * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. > +        */ > +       MEM_CGROUP_STAT_CACHE,     /* # of pages charged as cache */ > +       MEM_CGROUP_STAT_RSS,       /* # of pages charged as anon rss */ > +       MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */ > +       MEM_CGROUP_STAT_PGPGIN_COUNT,   /* # of pages paged in */ > +       MEM_CGROUP_STAT_PGPGOUT_COUNT,  /* # of pages paged out */ > +       MEM_CGROUP_STAT_EVENTS, /* sum of pagein + pageout for internal use */ > +       MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */ > +       MEM_CGROUP_STAT_SOFTLIMIT, /* decrements on each page in/out. > +                                       used by soft limit implementation */ > +       MEM_CGROUP_STAT_THRESHOLDS, /* decrements on each page in/out. > +                                       used by threshold implementation */ > +       MEM_CGROUP_STAT_FILE_DIRTY,   /* # of dirty pages in page cache */ > +       MEM_CGROUP_STAT_WRITEBACK,   /* # of pages under writeback */ > +       MEM_CGROUP_STAT_WRITEBACK_TEMP,   /* # of pages under writeback using > +                                               temporary buffers */ > +       MEM_CGROUP_STAT_UNSTABLE_NFS,   /* # of NFS unstable pages */ > + > +       MEM_CGROUP_STAT_NSTATS, > +}; > + >  #ifdef CONFIG_CGROUP_MEM_RES_CTLR >  /* >  * All "charge" functions with gfp_mask should use GFP_KERNEL or > @@ -117,6 +155,13 @@ extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, >  extern int do_swap_account; >  #endif > > +extern long mem_cgroup_dirty_ratio(void); > +extern unsigned long mem_cgroup_dirty_bytes(void); > +extern long mem_cgroup_dirty_background_ratio(void); > +extern unsigned long mem_cgroup_dirty_background_bytes(void); > + > +extern s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item); > + >  static inline bool mem_cgroup_disabled(void) >  { >        if (mem_cgroup_subsys.disabled) > @@ -125,7 +170,8 @@ static inline bool mem_cgroup_disabled(void) >  } > >  extern bool mem_cgroup_oom_called(struct task_struct *task); > -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); >  unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, >                                                gfp_t gfp_mask, int nid, >                                                int zid); > @@ -300,8 +346,8 @@ mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) >  { >  } > > -static inline void mem_cgroup_update_file_mapped(struct page *page, > -                                                       int val) > +static inline void mem_cgroup_update_stat(struct page *page, > +                       enum mem_cgroup_stat_index idx, int val) >  { >  } > > @@ -312,6 +358,31 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, >        return 0; >  } > > +static inline long mem_cgroup_dirty_ratio(void) > +{ > +       return vm_dirty_ratio; > +} > + > +static inline unsigned long mem_cgroup_dirty_bytes(void) > +{ > +       return vm_dirty_bytes; > +} > + > +static inline long mem_cgroup_dirty_background_ratio(void) > +{ > +       return dirty_background_ratio; > +} > + > +static inline unsigned long mem_cgroup_dirty_background_bytes(void) > +{ > +       return dirty_background_bytes; > +} > + > +static inline s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item) > +{ > +       return -ENOMEM; Why ENOMEM? Probably, EINVAL or ENOSYS? > +} > + >  #endif /* CONFIG_CGROUP_MEM_CONT */ > >  #endif /* _LINUX_MEMCONTROL_H */ > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index a443c30..e74cf66 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -66,31 +66,16 @@ static int really_do_swap_account __initdata = 1; /* for remember boot option*/ >  #define SOFTLIMIT_EVENTS_THRESH (1000) >  #define THRESHOLDS_EVENTS_THRESH (100) > > -/* > - * Statistics for memory cgroup. > - */ > -enum mem_cgroup_stat_index { > -       /* > -        * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. > -        */ > -       MEM_CGROUP_STAT_CACHE,     /* # of pages charged as cache */ > -       MEM_CGROUP_STAT_RSS,       /* # of pages charged as anon rss */ > -       MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */ > -       MEM_CGROUP_STAT_PGPGIN_COUNT,   /* # of pages paged in */ > -       MEM_CGROUP_STAT_PGPGOUT_COUNT,  /* # of pages paged out */ > -       MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */ > -       MEM_CGROUP_STAT_SOFTLIMIT, /* decrements on each page in/out. > -                                       used by soft limit implementation */ > -       MEM_CGROUP_STAT_THRESHOLDS, /* decrements on each page in/out. > -                                       used by threshold implementation */ > - > -       MEM_CGROUP_STAT_NSTATS, > -}; > - >  struct mem_cgroup_stat_cpu { >        s64 count[MEM_CGROUP_STAT_NSTATS]; >  }; > > +/* Per cgroup page statistics */ > +struct mem_cgroup_page_stat { > +       enum mem_cgroup_page_stat_item item; > +       s64 value; > +}; > + >  /* >  * per-zone information in memory controller. >  */ > @@ -157,6 +142,15 @@ struct mem_cgroup_threshold_ary { >  static bool mem_cgroup_threshold_check(struct mem_cgroup *mem); >  static void mem_cgroup_threshold(struct mem_cgroup *mem); > > +enum mem_cgroup_dirty_param { > +       MEM_CGROUP_DIRTY_RATIO, > +       MEM_CGROUP_DIRTY_BYTES, > +       MEM_CGROUP_DIRTY_BACKGROUND_RATIO, > +       MEM_CGROUP_DIRTY_BACKGROUND_BYTES, > + > +       MEM_CGROUP_DIRTY_NPARAMS, > +}; > + >  /* >  * The memory controller data structure. The memory controller controls both >  * page cache and RSS per cgroup. We would eventually like to provide > @@ -205,6 +199,9 @@ struct mem_cgroup { > >        unsigned int    swappiness; > > +       /* control memory cgroup dirty pages */ > +       unsigned long dirty_param[MEM_CGROUP_DIRTY_NPARAMS]; > + >        /* set when res.limit == memsw.limit */ >        bool            memsw_is_minimum; > > @@ -1021,6 +1018,164 @@ static unsigned int get_swappiness(struct mem_cgroup *memcg) >        return swappiness; >  } > > +static unsigned long get_dirty_param(struct mem_cgroup *memcg, > +                       enum mem_cgroup_dirty_param idx) > +{ > +       unsigned long ret; > + > +       VM_BUG_ON(idx >= MEM_CGROUP_DIRTY_NPARAMS); > +       spin_lock(&memcg->reclaim_param_lock); > +       ret = memcg->dirty_param[idx]; > +       spin_unlock(&memcg->reclaim_param_lock); > + > +       return ret; > +} > + > +long mem_cgroup_dirty_ratio(void) > +{ > +       struct mem_cgroup *memcg; > +       long ret = vm_dirty_ratio; > + > +       if (mem_cgroup_disabled()) > +               return ret; > +       /* > +        * It's possible that "current" may be moved to other cgroup while we > +        * access cgroup. But precise check is meaningless because the task can > +        * be moved after our access and writeback tends to take long time. > +        * At least, "memcg" will not be freed under rcu_read_lock(). > +        */ > +       rcu_read_lock(); > +       memcg = mem_cgroup_from_task(current); > +       if (likely(memcg)) > +               ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_RATIO); > +       rcu_read_unlock(); > + > +       return ret; > +} > + > +unsigned long mem_cgroup_dirty_bytes(void) > +{ > +       struct mem_cgroup *memcg; > +       unsigned long ret = vm_dirty_bytes; > + > +       if (mem_cgroup_disabled()) > +               return ret; > +       rcu_read_lock(); > +       memcg = mem_cgroup_from_task(current); > +       if (likely(memcg)) > +               ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_BYTES); > +       rcu_read_unlock(); > + > +       return ret; > +} > + > +long mem_cgroup_dirty_background_ratio(void) > +{ > +       struct mem_cgroup *memcg; > +       long ret = dirty_background_ratio; > + > +       if (mem_cgroup_disabled()) > +               return ret; > +       rcu_read_lock(); > +       memcg = mem_cgroup_from_task(current); > +       if (likely(memcg)) > +               ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_BACKGROUND_RATIO); > +       rcu_read_unlock(); > + > +       return ret; > +} > + > +unsigned long mem_cgroup_dirty_background_bytes(void) > +{ > +       struct mem_cgroup *memcg; > +       unsigned long ret = dirty_background_bytes; > + > +       if (mem_cgroup_disabled()) > +               return ret; > +       rcu_read_lock(); > +       memcg = mem_cgroup_from_task(current); > +       if (likely(memcg)) > +               ret = get_dirty_param(memcg, MEM_CGROUP_DIRTY_BACKGROUND_BYTES); > +       rcu_read_unlock(); > + > +       return ret; > +} > + > +static inline bool mem_cgroup_can_swap(struct mem_cgroup *memcg) > +{ > +       return do_swap_account ? > +                       res_counter_read_u64(&memcg->memsw, RES_LIMIT) : > +                       nr_swap_pages > 0; > +} > + > +static s64 mem_cgroup_get_local_page_stat(struct mem_cgroup *memcg, > +                               enum mem_cgroup_page_stat_item item) > +{ > +       s64 ret; > + > +       switch (item) { > +       case MEMCG_NR_DIRTYABLE_PAGES: > +               ret = res_counter_read_u64(&memcg->res, RES_LIMIT) - > +                       res_counter_read_u64(&memcg->res, RES_USAGE); > +               /* Translate free memory in pages */ > +               ret >>= PAGE_SHIFT; > +               ret += mem_cgroup_read_stat(memcg, LRU_ACTIVE_FILE) + > +                       mem_cgroup_read_stat(memcg, LRU_INACTIVE_FILE); > +               if (mem_cgroup_can_swap(memcg)) > +                       ret += mem_cgroup_read_stat(memcg, LRU_ACTIVE_ANON) + > +                               mem_cgroup_read_stat(memcg, LRU_INACTIVE_ANON); > +               break; > +       case MEMCG_NR_RECLAIM_PAGES: > +               ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_FILE_DIRTY) + > +                       mem_cgroup_read_stat(memcg, > +                                       MEM_CGROUP_STAT_UNSTABLE_NFS); > +               break; > +       case MEMCG_NR_WRITEBACK: > +               ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK); > +               break; > +       case MEMCG_NR_DIRTY_WRITEBACK_PAGES: > +               ret = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK) + > +                       mem_cgroup_read_stat(memcg, > +                               MEM_CGROUP_STAT_UNSTABLE_NFS); > +               break; > +       default: > +               ret = 0; > +               WARN_ON_ONCE(1); I think it's a bug, not warning. > +       } > +       return ret; > +} > + > +static int mem_cgroup_page_stat_cb(struct mem_cgroup *mem, void *data) > +{ > +       struct mem_cgroup_page_stat *stat = (struct mem_cgroup_page_stat *)data; > + > +       stat->value += mem_cgroup_get_local_page_stat(mem, stat->item); > +       return 0; > +} > + > +s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item) > +{ > +       struct mem_cgroup_page_stat stat = {}; > +       struct mem_cgroup *memcg; > + > +       if (mem_cgroup_disabled()) > +               return -ENOMEM; EINVAL/ENOSYS? > +       rcu_read_lock(); > +       memcg = mem_cgroup_from_task(current); > +       if (memcg) { > +               /* > +                * Recursively evaulate page statistics against all cgroup > +                * under hierarchy tree > +                */ > +               stat.item = item; > +               mem_cgroup_walk_tree(memcg, &stat, mem_cgroup_page_stat_cb); > +       } else > +               stat.value = -ENOMEM; ditto. > +       rcu_read_unlock(); > + > +       return stat.value; > +} > + >  static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data) >  { >        int *val = data; > @@ -1263,14 +1418,16 @@ 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 memory cgroup statistics. >  */ > -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) EXPORT_SYMBOL_GPL(mem_cgroup_update_stat) is needed, since it uses by filesystems. >  { >        struct mem_cgroup *mem; >        struct page_cgroup *pc; > > +       if (mem_cgroup_disabled()) > +               return; >        pc = lookup_page_cgroup(page); >        if (unlikely(!pc)) >                return; > @@ -1286,7 +1443,8 @@ void mem_cgroup_update_file_mapped(struct page *page, int val) >        /* >         * Preemption is already disabled. We can use __this_cpu_xxx >         */ > -       __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED], val); > +       VM_BUG_ON(idx >= MEM_CGROUP_STAT_NSTATS); > +       __this_cpu_add(mem->stat->count[idx], val); > >  done: >        unlock_page_cgroup(pc); > @@ -3033,6 +3191,10 @@ enum { >        MCS_PGPGIN, >        MCS_PGPGOUT, >        MCS_SWAP, > +       MCS_FILE_DIRTY, > +       MCS_WRITEBACK, > +       MCS_WRITEBACK_TEMP, > +       MCS_UNSTABLE_NFS, >        MCS_INACTIVE_ANON, >        MCS_ACTIVE_ANON, >        MCS_INACTIVE_FILE, > @@ -3055,6 +3217,10 @@ struct { >        {"pgpgin", "total_pgpgin"}, >        {"pgpgout", "total_pgpgout"}, >        {"swap", "total_swap"}, > +       {"filedirty", "dirty_pages"}, > +       {"writeback", "writeback_pages"}, > +       {"writeback_tmp", "writeback_temp_pages"}, > +       {"nfs", "nfs_unstable"}, >        {"inactive_anon", "total_inactive_anon"}, >        {"active_anon", "total_active_anon"}, >        {"inactive_file", "total_inactive_file"}, > @@ -3083,6 +3249,14 @@ static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data) >                val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT); >                s->stat[MCS_SWAP] += val * PAGE_SIZE; >        } > +       val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_DIRTY); > +       s->stat[MCS_FILE_DIRTY] += val; > +       val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_WRITEBACK); > +       s->stat[MCS_WRITEBACK] += val; > +       val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_WRITEBACK_TEMP); > +       s->stat[MCS_WRITEBACK_TEMP] += val; > +       val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_UNSTABLE_NFS); > +       s->stat[MCS_UNSTABLE_NFS] += val; > >        /* per zone stat */ >        val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON); > @@ -3467,6 +3641,50 @@ unlock: >        return ret; >  } > > +static u64 mem_cgroup_dirty_read(struct cgroup *cgrp, struct cftype *cft) > +{ > +       struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); > +       int type = cft->private; > + > +       return get_dirty_param(memcg, type); > +} > + > +static int > +mem_cgroup_dirty_write(struct cgroup *cgrp, struct cftype *cft, u64 val) > +{ > +       struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); > +       int type = cft->private; > + > +       if (cgrp->parent == NULL) > +               return -EINVAL; > +       if (((type == MEM_CGROUP_DIRTY_RATIO) || > +               (type == MEM_CGROUP_DIRTY_BACKGROUND_RATIO)) && (val > 100)) Too many unnecessary brackets if ((type == MEM_CGROUP_DIRTY_RATIO || type == MEM_CGROUP_DIRTY_BACKGROUND_RATIO) && val > 100) > +               return -EINVAL; > + > +       spin_lock(&memcg->reclaim_param_lock); > +       switch (type) { > +       case MEM_CGROUP_DIRTY_RATIO: > +               memcg->dirty_param[MEM_CGROUP_DIRTY_RATIO] = val; > +               memcg->dirty_param[MEM_CGROUP_DIRTY_BYTES] = 0; > +               break; > +       case MEM_CGROUP_DIRTY_BYTES: > +               memcg->dirty_param[MEM_CGROUP_DIRTY_RATIO] = 0; > +               memcg->dirty_param[MEM_CGROUP_DIRTY_BYTES] = val; > +               break; > +       case MEM_CGROUP_DIRTY_BACKGROUND_RATIO: > +               memcg->dirty_param[MEM_CGROUP_DIRTY_BACKGROUND_RATIO] = val; > +               memcg->dirty_param[MEM_CGROUP_DIRTY_BACKGROUND_BYTES] = 0; > +               break; > +       case MEM_CGROUP_DIRTY_BACKGROUND_BYTES: > +               memcg->dirty_param[MEM_CGROUP_DIRTY_BACKGROUND_RATIO] = 0; > +               memcg->dirty_param[MEM_CGROUP_DIRTY_BACKGROUND_BYTES] = val; > +               break; > +       } > +       spin_unlock(&memcg->reclaim_param_lock); > + > +       return 0; > +} > + >  static struct cftype mem_cgroup_files[] = { >        { >                .name = "usage_in_bytes", > @@ -3518,6 +3736,30 @@ static struct cftype mem_cgroup_files[] = { >                .write_u64 = mem_cgroup_swappiness_write, >        }, >        { > +               .name = "dirty_ratio", > +               .read_u64 = mem_cgroup_dirty_read, > +               .write_u64 = mem_cgroup_dirty_write, > +               .private = MEM_CGROUP_DIRTY_RATIO, > +       }, > +       { > +               .name = "dirty_bytes", > +               .read_u64 = mem_cgroup_dirty_read, > +               .write_u64 = mem_cgroup_dirty_write, > +               .private = MEM_CGROUP_DIRTY_BYTES, > +       }, > +       { > +               .name = "dirty_background_ratio", > +               .read_u64 = mem_cgroup_dirty_read, > +               .write_u64 = mem_cgroup_dirty_write, > +               .private = MEM_CGROUP_DIRTY_BACKGROUND_RATIO, > +       }, > +       { > +               .name = "dirty_background_bytes", > +               .read_u64 = mem_cgroup_dirty_read, > +               .write_u64 = mem_cgroup_dirty_write, > +               .private = MEM_CGROUP_DIRTY_BACKGROUND_BYTES, > +       }, > +       { >                .name = "move_charge_at_immigrate", >                .read_u64 = mem_cgroup_move_charge_read, >                .write_u64 = mem_cgroup_move_charge_write, > @@ -3725,6 +3967,19 @@ static int mem_cgroup_soft_limit_tree_init(void) >        return 0; >  } > > +/* > + * NOTE: called only with &src->reclaim_param_lock held from > + * mem_cgroup_create(). > + */ > +static inline void > +copy_dirty_params(struct mem_cgroup *dst, struct mem_cgroup *src) > +{ > +       int i; > + > +       for (i = 0; i < MEM_CGROUP_DIRTY_NPARAMS; i++) > +               dst->dirty_param[i] = src->dirty_param[i]; > +} > + >  static struct cgroup_subsys_state * __ref >  mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) >  { > @@ -3776,8 +4031,37 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) >        mem->last_scanned_child = 0; >        spin_lock_init(&mem->reclaim_param_lock); > > -       if (parent) > +       if (parent) { >                mem->swappiness = get_swappiness(parent); > + > +               spin_lock(&parent->reclaim_param_lock); > +               copy_dirty_params(mem, parent); > +               spin_unlock(&parent->reclaim_param_lock); > +       } else { > +               /* > +                * XXX: should we need a lock here? we could switch from > +                * vm_dirty_ratio to vm_dirty_bytes or vice versa but we're not > +                * reading them atomically. The same for dirty_background_ratio > +                * and dirty_background_bytes. > +                * > +                * For now, try to read them speculatively and retry if a > +                * "conflict" is detected. > +                */ > +               do { > +                       mem->dirty_param[MEM_CGROUP_DIRTY_RATIO] = > +                                               vm_dirty_ratio; > +                       mem->dirty_param[MEM_CGROUP_DIRTY_BYTES] = > +                                               vm_dirty_bytes; > +               } while (mem->dirty_param[MEM_CGROUP_DIRTY_RATIO] && > +                        mem->dirty_param[MEM_CGROUP_DIRTY_BYTES]); > +               do { > +                       mem->dirty_param[MEM_CGROUP_DIRTY_BACKGROUND_RATIO] = > +                                               dirty_background_ratio; > +                       mem->dirty_param[MEM_CGROUP_DIRTY_BACKGROUND_BYTES] = > +                                               dirty_background_bytes; > +               } while (mem->dirty_param[MEM_CGROUP_DIRTY_BACKGROUND_RATIO] && > +                       mem->dirty_param[MEM_CGROUP_DIRTY_BACKGROUND_BYTES]); > +       } >        atomic_set(&mem->refcnt, 1); >        mem->move_charge_at_immigrate = 0; >        mutex_init(&mem->thresholds_lock); > -- > 1.6.3.3 > >