Rework the victim range selection to also support file backed volatile ranges.
Cc: [email protected] Cc: Michael Kerrisk <[email protected]> Cc: Arun Sharma <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Neil Brown <[email protected]> Cc: Mike Hommey <[email protected]> Cc: Taras Glek <[email protected]> Cc: KOSAKI Motohiro <[email protected]> Cc: KAMEZAWA Hiroyuki <[email protected]> Cc: Jason Evans <[email protected]> Cc: [email protected] Cc: Paul Turner <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: Michel Lespinasse <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Minchan Kim <[email protected]> Signed-off-by: John Stultz <[email protected]> --- include/linux/vrange.h | 8 ++++ mm/vrange.c | 118 +++++++++++++++++++++++++++++++++--------------- 2 files changed, 89 insertions(+), 37 deletions(-) diff --git a/include/linux/vrange.h b/include/linux/vrange.h index 91960eb..bada2bd 100644 --- a/include/linux/vrange.h +++ b/include/linux/vrange.h @@ -47,6 +47,14 @@ static inline struct mm_struct *vrange_get_owner_mm(struct vrange *vrange) return container_of(vrange->owner, struct mm_struct, vroot); } +static inline +struct address_space *vrange_get_owner_mapping(struct vrange *vrange) +{ + if (vrange_type(vrange) != VRANGE_FILE) + return NULL; + return container_of(vrange->owner, struct address_space, vroot); +} + void vrange_init(void); extern void mm_exit_vrange(struct mm_struct *mm); diff --git a/mm/vrange.c b/mm/vrange.c index 671909c..b652513 100644 --- a/mm/vrange.c +++ b/mm/vrange.c @@ -690,8 +690,9 @@ static unsigned int discard_vma_pages(struct zone *zone, struct mm_struct *mm, return ret; } -unsigned int discard_vrange(struct zone *zone, struct vrange *vrange, - int nr_to_discard) +static unsigned int discard_anon_vrange(struct zone *zone, + struct vrange *vrange, + int nr_to_discard) { struct mm_struct *mm; unsigned long start = vrange->node.start; @@ -732,52 +733,91 @@ out: return nr_discarded; } +static unsigned int discard_file_vrange(struct zone *zone, + struct vrange *vrange, + int nr_to_discard) +{ + struct address_space *mapping; + unsigned long start = vrange->node.start; + unsigned long end = vrange->node.last; + unsigned long count = ((end-start) >> PAGE_CACHE_SHIFT); + + mapping = vrange_get_owner_mapping(vrange); + + truncate_inode_pages_range(mapping, start, end); + vrange->purged = true; + + return count; +} + +unsigned int discard_vrange(struct zone *zone, struct vrange *vrange, + int nr_to_discard) +{ + if (vrange_type(vrange) == VRANGE_ANON) + return discard_anon_vrange(zone, vrange, nr_to_discard); + return discard_file_vrange(zone, vrange, nr_to_discard); +} + + +/* Take a vrange refcount and depending on the type + * the vrange->owner's mm refcount or inode refcount + */ +static int hold_victim_vrange(struct vrange *vrange) +{ + if (vrange_type(vrange) == VRANGE_ANON) { + struct mm_struct *mm = vrange_get_owner_mm(vrange); + + + if (atomic_read(&mm->mm_users) == 0) + return -1; + + + if (!atomic_inc_not_zero(&vrange->refcount)) + return -1; + /* + * we need to access mmap_sem further routine so + * need to get a refcount of mm. + * NOTE: We guarantee mm_count isn't zero in here because + * if we found vrange from LRU list, it means we are + * before exit_vrange or remove_vrange. + */ + atomic_inc(&mm->mm_count); + } else { + struct address_space *mapping; + mapping = vrange_get_owner_mapping(vrange); + + if (!atomic_inc_not_zero(&vrange->refcount)) + return -1; + __iget(mapping->host); + } + + return 0; +} + + + /* - * Get next victim vrange from LRU and hold a vrange refcount - * and vrange->mm's refcount. + * Get next victim vrange from LRU and hold needed refcounts. */ static struct vrange *get_victim_vrange(void) { - struct mm_struct *mm; struct vrange *vrange = NULL; struct list_head *cur, *tmp; spin_lock(&lru_lock); list_for_each_prev_safe(cur, tmp, &lru_vrange) { vrange = list_entry(cur, struct vrange, lru); - mm = vrange_get_owner_mm(vrange); - - if (!mm) { - vrange = NULL; - continue; - } - /* the process is exiting so pass it */ - if (atomic_read(&mm->mm_users) == 0) { + if (hold_victim_vrange(vrange)) { list_del_init(&vrange->lru); vrange = NULL; continue; } - /* vrange is freeing so continue to loop */ - if (!atomic_inc_not_zero(&vrange->refcount)) { - list_del_init(&vrange->lru); - vrange = NULL; - continue; - } - - /* - * we need to access mmap_sem further routine so - * need to get a refcount of mm. - * NOTE: We guarantee mm_count isn't zero in here because - * if we found vrange from LRU list, it means we are - * before mm_exit_vrange or remove_vrange. - */ - atomic_inc(&mm->mm_count); - /* Isolate vrange */ list_del_init(&vrange->lru); break; + } spin_unlock(&lru_lock); @@ -786,11 +826,18 @@ static struct vrange *get_victim_vrange(void) static void put_victim_range(struct vrange *vrange) { - struct mm_struct *mm = vrange_get_owner_mm(vrange); - put_vrange(vrange); - if (mm) + + if (vrange_type(vrange) == VRANGE_ANON) { + struct mm_struct *mm = vrange_get_owner_mm(vrange); + mmdrop(mm); + } else { + struct address_space *mapping; + + mapping = vrange_get_owner_mapping(vrange); + iput(mapping->host); + } } unsigned int discard_vrange_pages(struct zone *zone, int nr_to_discard) @@ -799,11 +846,8 @@ unsigned int discard_vrange_pages(struct zone *zone, int nr_to_discard) unsigned int nr_discarded = 0; start_vrange = vrange = get_victim_vrange(); - if (start_vrange) { - struct mm_struct *mm = vrange_get_owner_mm(vrange); - atomic_inc(&start_vrange->refcount); - atomic_inc(&mm->mm_count); - } + if (start_vrange) + hold_victim_vrange(start_vrange); while (vrange) { nr_discarded += discard_vrange(zone, vrange, nr_to_discard); -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
