From: "Huang, Ying" <ying.huang@intel.com> To: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying <ying.huang@intel.com>, Johannes Weiner <hannes@cmpxchg.org>, Minchan Kim <minchan@kernel.org>, Hugh Dickins <hughd@google.com>, Shaohua Li <shli@kernel.org>, Rik van Riel <riel@redhat.com> Subject: [PATCH -mm -v3 02/12] mm, THP, swap: Support to reclaim swap space for THP swapped out Date: Mon, 24 Jul 2017 13:18:30 +0800 [thread overview] Message-ID: <20170724051840.2309-3-ying.huang@intel.com> (raw) In-Reply-To: <20170724051840.2309-1-ying.huang@intel.com> From: Huang Ying <ying.huang@intel.com> The normal swap slot reclaiming can be done when the swap count reaches SWAP_HAS_CACHE. But for the swap slot which is backing a THP, all swap slots backing one THP must be reclaimed together, because the swap slot may be used again when the THP is swapped out again later. So the swap slots backing one THP can be reclaimed together when the swap count for all swap slots for the THP reached SWAP_HAS_CACHE. In the patch, the functions to check whether the swap count for all swap slots backing one THP reached SWAP_HAS_CACHE are implemented and used when checking whether a swap slot can be reclaimed. To make it easier to determine whether a swap slot is backing a THP, a new swap cluster flag named CLUSTER_FLAG_HUGE is added to mark a swap cluster which is backing a THP (Transparent Huge Page). Because THP swap in as a whole isn't supported now. After deleting the THP from the swap cache (for example, swapping out finished), the CLUSTER_FLAG_HUGE flag will be cleared. So that, the normal pages inside THP can be swapped in individually. Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Shaohua Li <shli@kernel.org> Cc: Rik van Riel <riel@redhat.com> --- include/linux/swap.h | 1 + mm/swapfile.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++----- 2 files changed, 72 insertions(+), 7 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index d83d28e53e62..964b4f1fba4a 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -188,6 +188,7 @@ struct swap_cluster_info { }; #define CLUSTER_FLAG_FREE 1 /* This cluster is free */ #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ +#define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */ /* * We assign a cluster to each CPU, so each CPU can allocate swap entry from diff --git a/mm/swapfile.c b/mm/swapfile.c index c32e9b23d642..7db19846f8c7 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -265,6 +265,16 @@ static inline void cluster_set_null(struct swap_cluster_info *info) info->data = 0; } +static inline bool cluster_is_huge(struct swap_cluster_info *info) +{ + return info->flags & CLUSTER_FLAG_HUGE; +} + +static inline void cluster_clear_huge(struct swap_cluster_info *info) +{ + info->flags &= ~CLUSTER_FLAG_HUGE; +} + static inline struct swap_cluster_info *lock_cluster(struct swap_info_struct *si, unsigned long offset) { @@ -846,7 +856,7 @@ static int swap_alloc_cluster(struct swap_info_struct *si, swp_entry_t *slot) offset = idx * SWAPFILE_CLUSTER; ci = lock_cluster(si, offset); alloc_cluster(si, idx); - cluster_set_count_flag(ci, SWAPFILE_CLUSTER, 0); + cluster_set_count_flag(ci, SWAPFILE_CLUSTER, CLUSTER_FLAG_HUGE); map = si->swap_map + offset; for (i = 0; i < SWAPFILE_CLUSTER; i++) @@ -1176,6 +1186,7 @@ static void swapcache_free_cluster(swp_entry_t entry) return; ci = lock_cluster(si, offset); + VM_BUG_ON(!cluster_is_huge(ci)); map = si->swap_map + offset; for (i = 0; i < SWAPFILE_CLUSTER; i++) { val = map[i]; @@ -1187,6 +1198,7 @@ static void swapcache_free_cluster(swp_entry_t entry) for (i = 0; i < SWAPFILE_CLUSTER; i++) map[i] &= ~SWAP_HAS_CACHE; } + cluster_clear_huge(ci); unlock_cluster(ci); if (free_entries == SWAPFILE_CLUSTER) { spin_lock(&si->lock); @@ -1350,6 +1362,54 @@ int swp_swapcount(swp_entry_t entry) return count; } +#ifdef CONFIG_THP_SWAP +static bool swap_page_trans_huge_swapped(struct swap_info_struct *si, + swp_entry_t entry) +{ + struct swap_cluster_info *ci; + unsigned char *map = si->swap_map; + unsigned long roffset = swp_offset(entry); + unsigned long offset = round_down(roffset, SWAPFILE_CLUSTER); + int i; + bool ret = false; + + ci = lock_cluster_or_swap_info(si, offset); + if (!cluster_is_huge(ci)) { + if (map[roffset] != SWAP_HAS_CACHE) + ret = true; + goto unlock_out; + } + for (i = 0; i < SWAPFILE_CLUSTER; i++) { + if (map[offset + i] != SWAP_HAS_CACHE) { + ret = true; + break; + } + } +unlock_out: + unlock_cluster_or_swap_info(si, ci); + return ret; +} + +static bool page_swapped(struct page *page) +{ + swp_entry_t entry; + struct swap_info_struct *si; + + if (likely(!PageTransCompound(page))) + return page_swapcount(page) != 0; + + page = compound_head(page); + entry.val = page_private(page); + si = _swap_info_get(entry); + if (si) + return swap_page_trans_huge_swapped(si, entry); + return false; +} +#else +#define swap_page_trans_huge_swapped(si, entry) swap_swapcount(si, entry) +#define page_swapped(page) (page_swapcount(page) != 0) +#endif + /* * We can write to an anon page without COW if there are no other references * to it. And as a side-effect, free up its swap: because the old content @@ -1404,7 +1464,7 @@ int try_to_free_swap(struct page *page) return 0; if (PageWriteback(page)) return 0; - if (page_swapcount(page)) + if (page_swapped(page)) return 0; /* @@ -1425,6 +1485,7 @@ int try_to_free_swap(struct page *page) if (pm_suspended_storage()) return 0; + page = compound_head(page); delete_from_swap_cache(page); SetPageDirty(page); return 1; @@ -1446,7 +1507,8 @@ int free_swap_and_cache(swp_entry_t entry) p = _swap_info_get(entry); if (p) { count = __swap_entry_free(p, entry, 1); - if (count == SWAP_HAS_CACHE) { + 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)) { @@ -1463,7 +1525,8 @@ int free_swap_and_cache(swp_entry_t entry) */ if (PageSwapCache(page) && !PageWriteback(page) && (!page_mapped(page) || mem_cgroup_swap_full(page)) && - !swap_swapcount(p, entry)) { + !swap_page_trans_huge_swapped(p, entry)) { + page = compound_head(page); delete_from_swap_cache(page); SetPageDirty(page); } @@ -2017,7 +2080,7 @@ int try_to_unuse(unsigned int type, bool frontswap, .sync_mode = WB_SYNC_NONE, }; - swap_writepage(page, &wbc); + swap_writepage(compound_head(page), &wbc); lock_page(page); wait_on_page_writeback(page); } @@ -2030,8 +2093,9 @@ int try_to_unuse(unsigned int type, bool frontswap, * delete, since it may not have been written out to swap yet. */ if (PageSwapCache(page) && - likely(page_private(page) == entry.val)) - delete_from_swap_cache(page); + likely(page_private(page) == entry.val) && + !page_swapped(page)) + delete_from_swap_cache(compound_head(page)); /* * So we could skip searching mms once swap count went -- 2.13.2
WARNING: multiple messages have this Message-ID (diff)
From: "Huang, Ying" <ying.huang@intel.com> To: Andrew Morton <akpm@linux-foundation.org> Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying <ying.huang@intel.com>, Johannes Weiner <hannes@cmpxchg.org>, Minchan Kim <minchan@kernel.org>, Hugh Dickins <hughd@google.com>, Shaohua Li <shli@kernel.org>, Rik van Riel <riel@redhat.com> Subject: [PATCH -mm -v3 02/12] mm, THP, swap: Support to reclaim swap space for THP swapped out Date: Mon, 24 Jul 2017 13:18:30 +0800 [thread overview] Message-ID: <20170724051840.2309-3-ying.huang@intel.com> (raw) In-Reply-To: <20170724051840.2309-1-ying.huang@intel.com> From: Huang Ying <ying.huang@intel.com> The normal swap slot reclaiming can be done when the swap count reaches SWAP_HAS_CACHE. But for the swap slot which is backing a THP, all swap slots backing one THP must be reclaimed together, because the swap slot may be used again when the THP is swapped out again later. So the swap slots backing one THP can be reclaimed together when the swap count for all swap slots for the THP reached SWAP_HAS_CACHE. In the patch, the functions to check whether the swap count for all swap slots backing one THP reached SWAP_HAS_CACHE are implemented and used when checking whether a swap slot can be reclaimed. To make it easier to determine whether a swap slot is backing a THP, a new swap cluster flag named CLUSTER_FLAG_HUGE is added to mark a swap cluster which is backing a THP (Transparent Huge Page). Because THP swap in as a whole isn't supported now. After deleting the THP from the swap cache (for example, swapping out finished), the CLUSTER_FLAG_HUGE flag will be cleared. So that, the normal pages inside THP can be swapped in individually. Signed-off-by: "Huang, Ying" <ying.huang@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Shaohua Li <shli@kernel.org> Cc: Rik van Riel <riel@redhat.com> --- include/linux/swap.h | 1 + mm/swapfile.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++----- 2 files changed, 72 insertions(+), 7 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index d83d28e53e62..964b4f1fba4a 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -188,6 +188,7 @@ struct swap_cluster_info { }; #define CLUSTER_FLAG_FREE 1 /* This cluster is free */ #define CLUSTER_FLAG_NEXT_NULL 2 /* This cluster has no next cluster */ +#define CLUSTER_FLAG_HUGE 4 /* This cluster is backing a transparent huge page */ /* * We assign a cluster to each CPU, so each CPU can allocate swap entry from diff --git a/mm/swapfile.c b/mm/swapfile.c index c32e9b23d642..7db19846f8c7 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -265,6 +265,16 @@ static inline void cluster_set_null(struct swap_cluster_info *info) info->data = 0; } +static inline bool cluster_is_huge(struct swap_cluster_info *info) +{ + return info->flags & CLUSTER_FLAG_HUGE; +} + +static inline void cluster_clear_huge(struct swap_cluster_info *info) +{ + info->flags &= ~CLUSTER_FLAG_HUGE; +} + static inline struct swap_cluster_info *lock_cluster(struct swap_info_struct *si, unsigned long offset) { @@ -846,7 +856,7 @@ static int swap_alloc_cluster(struct swap_info_struct *si, swp_entry_t *slot) offset = idx * SWAPFILE_CLUSTER; ci = lock_cluster(si, offset); alloc_cluster(si, idx); - cluster_set_count_flag(ci, SWAPFILE_CLUSTER, 0); + cluster_set_count_flag(ci, SWAPFILE_CLUSTER, CLUSTER_FLAG_HUGE); map = si->swap_map + offset; for (i = 0; i < SWAPFILE_CLUSTER; i++) @@ -1176,6 +1186,7 @@ static void swapcache_free_cluster(swp_entry_t entry) return; ci = lock_cluster(si, offset); + VM_BUG_ON(!cluster_is_huge(ci)); map = si->swap_map + offset; for (i = 0; i < SWAPFILE_CLUSTER; i++) { val = map[i]; @@ -1187,6 +1198,7 @@ static void swapcache_free_cluster(swp_entry_t entry) for (i = 0; i < SWAPFILE_CLUSTER; i++) map[i] &= ~SWAP_HAS_CACHE; } + cluster_clear_huge(ci); unlock_cluster(ci); if (free_entries == SWAPFILE_CLUSTER) { spin_lock(&si->lock); @@ -1350,6 +1362,54 @@ int swp_swapcount(swp_entry_t entry) return count; } +#ifdef CONFIG_THP_SWAP +static bool swap_page_trans_huge_swapped(struct swap_info_struct *si, + swp_entry_t entry) +{ + struct swap_cluster_info *ci; + unsigned char *map = si->swap_map; + unsigned long roffset = swp_offset(entry); + unsigned long offset = round_down(roffset, SWAPFILE_CLUSTER); + int i; + bool ret = false; + + ci = lock_cluster_or_swap_info(si, offset); + if (!cluster_is_huge(ci)) { + if (map[roffset] != SWAP_HAS_CACHE) + ret = true; + goto unlock_out; + } + for (i = 0; i < SWAPFILE_CLUSTER; i++) { + if (map[offset + i] != SWAP_HAS_CACHE) { + ret = true; + break; + } + } +unlock_out: + unlock_cluster_or_swap_info(si, ci); + return ret; +} + +static bool page_swapped(struct page *page) +{ + swp_entry_t entry; + struct swap_info_struct *si; + + if (likely(!PageTransCompound(page))) + return page_swapcount(page) != 0; + + page = compound_head(page); + entry.val = page_private(page); + si = _swap_info_get(entry); + if (si) + return swap_page_trans_huge_swapped(si, entry); + return false; +} +#else +#define swap_page_trans_huge_swapped(si, entry) swap_swapcount(si, entry) +#define page_swapped(page) (page_swapcount(page) != 0) +#endif + /* * We can write to an anon page without COW if there are no other references * to it. And as a side-effect, free up its swap: because the old content @@ -1404,7 +1464,7 @@ int try_to_free_swap(struct page *page) return 0; if (PageWriteback(page)) return 0; - if (page_swapcount(page)) + if (page_swapped(page)) return 0; /* @@ -1425,6 +1485,7 @@ int try_to_free_swap(struct page *page) if (pm_suspended_storage()) return 0; + page = compound_head(page); delete_from_swap_cache(page); SetPageDirty(page); return 1; @@ -1446,7 +1507,8 @@ int free_swap_and_cache(swp_entry_t entry) p = _swap_info_get(entry); if (p) { count = __swap_entry_free(p, entry, 1); - if (count == SWAP_HAS_CACHE) { + 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)) { @@ -1463,7 +1525,8 @@ int free_swap_and_cache(swp_entry_t entry) */ if (PageSwapCache(page) && !PageWriteback(page) && (!page_mapped(page) || mem_cgroup_swap_full(page)) && - !swap_swapcount(p, entry)) { + !swap_page_trans_huge_swapped(p, entry)) { + page = compound_head(page); delete_from_swap_cache(page); SetPageDirty(page); } @@ -2017,7 +2080,7 @@ int try_to_unuse(unsigned int type, bool frontswap, .sync_mode = WB_SYNC_NONE, }; - swap_writepage(page, &wbc); + swap_writepage(compound_head(page), &wbc); lock_page(page); wait_on_page_writeback(page); } @@ -2030,8 +2093,9 @@ int try_to_unuse(unsigned int type, bool frontswap, * delete, since it may not have been written out to swap yet. */ if (PageSwapCache(page) && - likely(page_private(page) == entry.val)) - delete_from_swap_cache(page); + likely(page_private(page) == entry.val) && + !page_swapped(page)) + delete_from_swap_cache(compound_head(page)); /* * So we could skip searching mms once swap count went -- 2.13.2 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-07-24 5:19 UTC|newest] Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-07-24 5:18 [PATCH -mm -v3 00/12] mm, THP, swap: Delay splitting THP after swapped out Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` [PATCH -mm -v3 01/12] mm, THP, swap: Support to clear swap cache flag for THP " Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-25 16:39 ` Rik van Riel 2017-07-24 5:18 ` Huang, Ying [this message] 2017-07-24 5:18 ` [PATCH -mm -v3 02/12] mm, THP, swap: Support to reclaim swap space " Huang, Ying 2017-07-25 17:47 ` Rik van Riel 2017-07-24 5:18 ` [PATCH -mm -v3 03/12] mm, THP, swap: Make reuse_swap_page() works " Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` [PATCH -mm -v3 04/12] mm, THP, swap: Don't allocate huge cluster for file backed swap device Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` [PATCH -mm -v3 05/12] block, THP: Make block_device_operations.rw_page support THP Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` [PATCH -mm -v3 06/12] Test code to write THP to swap device as a whole Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` [PATCH -mm -v3 07/12] mm, THP, swap: Support to split THP for THP swapped out Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` [PATCH -mm -v3 08/12] memcg, THP, swap: Support move mem cgroup charge " Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` [PATCH -mm -v3 09/12] memcg, THP, swap: Avoid to duplicated charge THP in swap cache Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` [PATCH -mm -v3 10/12] memcg, THP, swap: Make mem_cgroup_swapout() support THP Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` [PATCH -mm -v3 11/12] mm, THP, swap: Delay splitting THP after swapped out Huang, Ying 2017-07-24 5:18 ` Huang, Ying 2017-07-24 5:18 ` [PATCH -mm -v3 12/12] mm, THP, swap: Add THP swapping out fallback counting Huang, Ying 2017-07-24 5:18 ` Huang, Ying
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20170724051840.2309-3-ying.huang@intel.com \ --to=ying.huang@intel.com \ --cc=akpm@linux-foundation.org \ --cc=hannes@cmpxchg.org \ --cc=hughd@google.com \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=minchan@kernel.org \ --cc=riel@redhat.com \ --cc=shli@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.