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 <arighi@xxxxxxxxxxx> --- include/linux/memcontrol.h | 80 ++++++++- mm/memcontrol.c | 420 +++++++++++++++++++++++++++++++++++++++----- 2 files changed, 450 insertions(+), 50 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 1f9b119..cc3421b 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -19,12 +19,66 @@ #ifndef _LINUX_MEMCONTROL_H #define _LINUX_MEMCONTROL_H + +#include <linux/writeback.h> #include <linux/cgroup.h> + 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, +}; + +/* Dirty memory parameters */ +struct dirty_param { + int dirty_ratio; + unsigned long dirty_bytes; + int dirty_background_ratio; + unsigned long dirty_background_bytes; +}; + +/* + * 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_EVENTS, /* incremented at every pagein/pageout */ + 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, +}; + +/* + * TODO: provide a validation check routine. And retry if validation + * fails. + */ +static inline void get_global_dirty_param(struct dirty_param *param) +{ + param->dirty_ratio = vm_dirty_ratio; + param->dirty_bytes = vm_dirty_bytes; + param->dirty_background_ratio = dirty_background_ratio; + param->dirty_background_bytes = dirty_background_bytes; +} + #ifdef CONFIG_CGROUP_MEM_RES_CTLR /* * All "charge" functions with gfp_mask should use GFP_KERNEL or @@ -117,6 +171,10 @@ extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, extern int do_swap_account; #endif +extern bool mem_cgroup_has_dirty_limit(void); +extern void get_dirty_param(struct dirty_param *param); +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 +183,8 @@ 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 +359,8 @@ 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 +371,21 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, return 0; } +static inline bool mem_cgroup_has_dirty_limit(void) +{ + return false; +} + +static inline void get_dirty_param(struct dirty_param *param) +{ + get_global_dirty_param(param); +} + +static inline s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item) +{ + return -ENOSYS; +} + #endif /* CONFIG_CGROUP_MEM_CONT */ #endif /* _LINUX_MEMCONTROL_H */ diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 497b6f7..9842e7b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -73,28 +73,23 @@ static int really_do_swap_account __initdata = 1; /* for remember boot option*/ #define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */ #define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */ -/* - * 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_EVENTS, /* incremented at every pagein/pageout */ - - 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; +}; + +enum { + MEM_CGROUP_DIRTY_RATIO, + MEM_CGROUP_DIRTY_BYTES, + MEM_CGROUP_DIRTY_BACKGROUND_RATIO, + MEM_CGROUP_DIRTY_BACKGROUND_BYTES, +}; + /* * per-zone information in memory controller. */ @@ -208,6 +203,9 @@ struct mem_cgroup { unsigned int swappiness; + /* control memory cgroup dirty pages */ + struct dirty_param dirty_param; + /* set when res.limit == memsw.limit */ bool memsw_is_minimum; @@ -1033,6 +1031,156 @@ static unsigned int get_swappiness(struct mem_cgroup *memcg) return swappiness; } +static bool dirty_param_is_valid(struct dirty_param *param) +{ + if (param->dirty_ratio && param->dirty_bytes) + return false; + if (param->dirty_background_ratio && param->dirty_background_bytes) + return false; + return true; +} + +static void +__mem_cgroup_get_dirty_param(struct dirty_param *param, struct mem_cgroup *mem) +{ + param->dirty_ratio = mem->dirty_param.dirty_ratio; + param->dirty_bytes = mem->dirty_param.dirty_bytes; + param->dirty_background_ratio = mem->dirty_param.dirty_background_ratio; + param->dirty_background_bytes = mem->dirty_param.dirty_background_bytes; +} + +/* + * get_dirty_param() - get dirty memory parameters of the current memcg + * @param: a structure is filled with the dirty memory settings + * + * The function fills @param with the current memcg dirty memory settings. If + * memory cgroup is disabled or in case of error the structure is filled with + * the global dirty memory settings. + */ +void get_dirty_param(struct dirty_param *param) +{ + struct mem_cgroup *memcg; + + if (mem_cgroup_disabled()) { + get_global_dirty_param(param); + return; + } + /* + * 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(). + */ + while (1) { + rcu_read_lock(); + memcg = mem_cgroup_from_task(current); + if (likely(memcg)) + __mem_cgroup_get_dirty_param(param, memcg); + else + get_global_dirty_param(param); + rcu_read_unlock(); + /* + * Since global and memcg dirty_param are not protected we try + * to speculatively read them and retry if we get inconsistent + * values. + */ + if (likely(dirty_param_is_valid(param))) + break; + } +} + +static inline bool mem_cgroup_can_swap(struct mem_cgroup *memcg) +{ + if (!do_swap_account) + return nr_swap_pages > 0; + return !memcg->memsw_is_minimum && + (res_counter_read_u64(&memcg->memsw, RES_LIMIT) > 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: + BUG_ON(1); + } + 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; +} + +/* + * mem_cgroup_has_dirty_limit() - check if current memcg has local dirty limits + * + * Return true if the current memory cgroup has local dirty memory settings, + * false otherwise. + */ +bool mem_cgroup_has_dirty_limit(void) +{ + if (mem_cgroup_disabled()) + return false; + return mem_cgroup_from_task(current) != NULL; +} + +/* + * mem_cgroup_page_stat() - get memory cgroup file cache statistics + * @item: memory statistic item exported to the kernel + * + * Return the accounted statistic value, or a negative value in case of error. + */ +s64 mem_cgroup_page_stat(enum mem_cgroup_page_stat_item item) +{ + struct mem_cgroup_page_stat stat = {}; + struct mem_cgroup *memcg; + + 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 = -EINVAL; + rcu_read_unlock(); + + return stat.value; +} + 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. */ -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) { 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. + */ +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(); /* * We charges against "to" which may not have any tasks. Then, "to" * can be under rmdir(). But in current implementation, caller of @@ -3042,6 +3261,10 @@ 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, @@ -3064,6 +3287,10 @@ 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"}, @@ -3092,6 +3319,14 @@ 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); @@ -3453,6 +3688,60 @@ unlock: return ret; } +static u64 mem_cgroup_dirty_read(struct cgroup *cgrp, struct cftype *cft) +{ + struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); + + switch (cft->private) { + case MEM_CGROUP_DIRTY_RATIO: + return memcg->dirty_param.dirty_ratio; + case MEM_CGROUP_DIRTY_BYTES: + return memcg->dirty_param.dirty_bytes; + case MEM_CGROUP_DIRTY_BACKGROUND_RATIO: + return memcg->dirty_param.dirty_background_ratio; + case MEM_CGROUP_DIRTY_BACKGROUND_BYTES: + return memcg->dirty_param.dirty_background_bytes; + default: + BUG(); + } +} + +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) + return -EINVAL; + /* + * TODO: provide a validation check routine. And retry if validation + * fails. + */ + switch (type) { + case MEM_CGROUP_DIRTY_RATIO: + memcg->dirty_param.dirty_ratio = val; + memcg->dirty_param.dirty_bytes = 0; + break; + case MEM_CGROUP_DIRTY_BYTES: + memcg->dirty_param.dirty_ratio = 0; + memcg->dirty_param.dirty_bytes = val; + break; + case MEM_CGROUP_DIRTY_BACKGROUND_RATIO: + memcg->dirty_param.dirty_background_ratio = val; + memcg->dirty_param.dirty_background_bytes = 0; + break; + case MEM_CGROUP_DIRTY_BACKGROUND_BYTES: + memcg->dirty_param.dirty_background_ratio = 0; + memcg->dirty_param.dirty_background_bytes = val; + break; + } + return 0; +} + static struct cftype mem_cgroup_files[] = { { .name = "usage_in_bytes", @@ -3504,6 +3793,30 @@ 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, @@ -3762,8 +4075,21 @@ 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); + mem->dirty_param = parent->dirty_param; + } else { + while (1) { + get_global_dirty_param(&mem->dirty_param); + /* + * Since global dirty parameters are not protected we + * try to speculatively read them and retry if we get + * inconsistent values. + */ + if (likely(dirty_param_is_valid(&mem->dirty_param))) + break; + } + } atomic_set(&mem->refcnt, 1); mem->move_charge_at_immigrate = 0; mutex_init(&mem->thresholds_lock); -- 1.6.3.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . 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