diff options
Diffstat (limited to 'mm/swapfile.c')
| -rw-r--r-- | mm/swapfile.c | 83 |
1 files changed, 38 insertions, 45 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index d954b71c4f9c..644f746e167a 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -103,26 +103,39 @@ static inline unsigned char swap_count(unsigned char ent) return ent & ~SWAP_HAS_CACHE; /* may include COUNT_CONTINUED flag */ } +/* Reclaim the swap entry anyway if possible */ +#define TTRS_ANYWAY 0x1 +/* + * Reclaim the swap entry if there are no more mappings of the + * corresponding page + */ +#define TTRS_UNMAPPED 0x2 +/* Reclaim the swap entry if swap is getting full*/ +#define TTRS_FULL 0x4 + /* returns 1 if swap entry is freed */ -static int -__try_to_reclaim_swap(struct swap_info_struct *si, unsigned long offset) +static int __try_to_reclaim_swap(struct swap_info_struct *si, + unsigned long offset, unsigned long flags) { swp_entry_t entry = swp_entry(si->type, offset); struct page *page; int ret = 0; - page = find_get_page(swap_address_space(entry), swp_offset(entry)); + page = find_get_page(swap_address_space(entry), offset); if (!page) return 0; /* - * This function is called from scan_swap_map() and it's called - * by vmscan.c at reclaiming pages. So, we hold a lock on a page, here. - * We have to use trylock for avoiding deadlock. This is a special + * When this function is called from scan_swap_map_slots() and it's + * called by vmscan.c at reclaiming pages. So, we hold a lock on a page, + * here. We have to use trylock for avoiding deadlock. This is a special * case and you should use try_to_free_swap() with explicit lock_page() * in usual operations. */ if (trylock_page(page)) { - ret = try_to_free_swap(page); + if ((flags & TTRS_ANYWAY) || + ((flags & TTRS_UNMAPPED) && !page_mapped(page)) || + ((flags & TTRS_FULL) && mem_cgroup_swap_full(page))) + ret = try_to_free_swap(page); unlock_page(page); } put_page(page); @@ -780,7 +793,7 @@ checks: int swap_was_freed; unlock_cluster(ci); spin_unlock(&si->lock); - swap_was_freed = __try_to_reclaim_swap(si, offset); + swap_was_freed = __try_to_reclaim_swap(si, offset, TTRS_ANYWAY); spin_lock(&si->lock); /* entry was freed successfully, try to use this again */ if (swap_was_freed) @@ -919,6 +932,7 @@ static void swap_free_cluster(struct swap_info_struct *si, unsigned long idx) struct swap_cluster_info *ci; ci = lock_cluster(si, offset); + memset(si->swap_map + offset, 0, SWAPFILE_CLUSTER); cluster_set_count_flag(ci, 0, 0); free_cluster(si, idx); unlock_cluster(ci); @@ -989,7 +1003,7 @@ start_over: goto nextsi; } if (size == SWAPFILE_CLUSTER) { - if (!(si->flags & SWP_FILE)) + if (!(si->flags & SWP_FS)) n_ret = swap_alloc_cluster(si, swp_entries); } else n_ret = scan_swap_map_slots(si, SWAP_HAS_CACHE, @@ -1169,6 +1183,8 @@ static unsigned char __swap_entry_free(struct swap_info_struct *p, ci = lock_cluster_or_swap_info(p, offset); usage = __swap_entry_free_locked(p, offset, usage); unlock_cluster_or_swap_info(p, ci); + if (!usage) + free_swap_slot(entry); return usage; } @@ -1199,10 +1215,8 @@ void swap_free(swp_entry_t entry) struct swap_info_struct *p; p = _swap_info_get(entry); - if (p) { - if (!__swap_entry_free(p, entry, 1)) - free_swap_slot(entry); - } + if (p) + __swap_entry_free(p, entry, 1); } /* @@ -1237,9 +1251,6 @@ void put_swap_page(struct page *page, swp_entry_t entry) if (free_entries == SWAPFILE_CLUSTER) { unlock_cluster_or_swap_info(si, ci); spin_lock(&si->lock); - ci = lock_cluster(si, offset); - memset(map, 0, SWAPFILE_CLUSTER); - unlock_cluster(ci); mem_cgroup_uncharge_swap(entry, SWAPFILE_CLUSTER); swap_free_cluster(si, idx); spin_unlock(&si->lock); @@ -1612,7 +1623,6 @@ int try_to_free_swap(struct page *page) int free_swap_and_cache(swp_entry_t entry) { struct swap_info_struct *p; - struct page *page = NULL; unsigned char count; if (non_swap_entry(entry)) @@ -1622,30 +1632,9 @@ int free_swap_and_cache(swp_entry_t entry) if (p) { count = __swap_entry_free(p, entry, 1); if (count == SWAP_HAS_CACHE && - !swap_page_trans_huge_swapped(p, entry)) { - page = find_get_page(swap_address_space(entry), - swp_offset(entry)); - if (page && !trylock_page(page)) { - put_page(page); - page = NULL; - } - } else if (!count) - free_swap_slot(entry); - } - if (page) { - /* - * Not mapped elsewhere, or swap space full? Free it! - * Also recheck PageSwapCache now page is locked (above). - */ - if (PageSwapCache(page) && !PageWriteback(page) && - (!page_mapped(page) || mem_cgroup_swap_full(page)) && - !swap_page_trans_huge_swapped(p, entry)) { - page = compound_head(page); - delete_from_swap_cache(page); - SetPageDirty(page); - } - unlock_page(page); - put_page(page); + !swap_page_trans_huge_swapped(p, entry)) + __try_to_reclaim_swap(p, swp_offset(entry), + TTRS_UNMAPPED | TTRS_FULL); } return p != NULL; } @@ -2310,12 +2299,13 @@ static void destroy_swap_extents(struct swap_info_struct *sis) kfree(se); } - if (sis->flags & SWP_FILE) { + if (sis->flags & SWP_ACTIVATED) { struct file *swap_file = sis->swap_file; struct address_space *mapping = swap_file->f_mapping; - sis->flags &= ~SWP_FILE; - mapping->a_ops->swap_deactivate(swap_file); + sis->flags &= ~SWP_ACTIVATED; + if (mapping->a_ops->swap_deactivate) + mapping->a_ops->swap_deactivate(swap_file); } } @@ -2364,6 +2354,7 @@ add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, list_add_tail(&new_se->list, &sis->first_swap_extent.list); return 1; } +EXPORT_SYMBOL_GPL(add_swap_extent); /* * A `swap extent' is a simple thing which maps a contiguous range of pages @@ -2411,8 +2402,10 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) if (mapping->a_ops->swap_activate) { ret = mapping->a_ops->swap_activate(sis, swap_file, span); + if (ret >= 0) + sis->flags |= SWP_ACTIVATED; if (!ret) { - sis->flags |= SWP_FILE; + sis->flags |= SWP_FS; ret = add_swap_extent(sis, 0, sis->max, 0); *span = sis->pages; } |