diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/Kconfig | 17 | ||||
| -rw-r--r-- | mm/Makefile | 1 | ||||
| -rw-r--r-- | mm/frontswap.c | 314 | ||||
| -rw-r--r-- | mm/memblock.c | 68 | ||||
| -rw-r--r-- | mm/memcontrol.c | 6 | ||||
| -rw-r--r-- | mm/memory.c | 12 | ||||
| -rw-r--r-- | mm/mempolicy.c | 2 | ||||
| -rw-r--r-- | mm/nommu.c | 2 | ||||
| -rw-r--r-- | mm/oom_kill.c | 21 | ||||
| -rw-r--r-- | mm/page_cgroup.c | 4 | ||||
| -rw-r--r-- | mm/page_io.c | 12 | ||||
| -rw-r--r-- | mm/pagewalk.c | 1 | ||||
| -rw-r--r-- | mm/percpu-vm.c | 1 | ||||
| -rw-r--r-- | mm/shmem.c | 57 | ||||
| -rw-r--r-- | mm/swapfile.c | 66 |
15 files changed, 511 insertions, 73 deletions
diff --git a/mm/Kconfig b/mm/Kconfig index b2176374b98e..82fed4eb2b6f 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -389,3 +389,20 @@ config CLEANCACHE in a negligible performance hit. If unsure, say Y to enable cleancache + +config FRONTSWAP + bool "Enable frontswap to cache swap pages if tmem is present" + depends on SWAP + default n + help + Frontswap is so named because it can be thought of as the opposite + of a "backing" store for a swap device. The data is stored into + "transcendent memory", memory that is not directly accessible or + addressable by the kernel and is of unknown and possibly + time-varying size. When space in transcendent memory is available, + a significant swap I/O reduction may be achieved. When none is + available, all frontswap calls are reduced to a single pointer- + compare-against-NULL resulting in a negligible performance hit + and swap data is stored as normal on the matching swap device. + + If unsure, say Y to enable frontswap. diff --git a/mm/Makefile b/mm/Makefile index a156285ce88d..2e2fbbefb99f 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -29,6 +29,7 @@ obj-$(CONFIG_HAVE_MEMBLOCK) += memblock.o obj-$(CONFIG_BOUNCE) += bounce.o obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o +obj-$(CONFIG_FRONTSWAP) += frontswap.o obj-$(CONFIG_HAS_DMA) += dmapool.o obj-$(CONFIG_HUGETLBFS) += hugetlb.o obj-$(CONFIG_NUMA) += mempolicy.o diff --git a/mm/frontswap.c b/mm/frontswap.c new file mode 100644 index 000000000000..e25025574a02 --- /dev/null +++ b/mm/frontswap.c @@ -0,0 +1,314 @@ +/* + * Frontswap frontend + * + * This code provides the generic "frontend" layer to call a matching + * "backend" driver implementation of frontswap. See + * Documentation/vm/frontswap.txt for more information. + * + * Copyright (C) 2009-2012 Oracle Corp. All rights reserved. + * Author: Dan Magenheimer + * + * This work is licensed under the terms of the GNU GPL, version 2. + */ + +#include <linux/mm.h> +#include <linux/mman.h> +#include <linux/swap.h> +#include <linux/swapops.h> +#include <linux/proc_fs.h> +#include <linux/security.h> +#include <linux/capability.h> +#include <linux/module.h> +#include <linux/uaccess.h> +#include <linux/debugfs.h> +#include <linux/frontswap.h> +#include <linux/swapfile.h> + +/* + * frontswap_ops is set by frontswap_register_ops to contain the pointers + * to the frontswap "backend" implementation functions. + */ +static struct frontswap_ops frontswap_ops __read_mostly; + +/* + * This global enablement flag reduces overhead on systems where frontswap_ops + * has not been registered, so is preferred to the slower alternative: a + * function call that checks a non-global. + */ +bool frontswap_enabled __read_mostly; +EXPORT_SYMBOL(frontswap_enabled); + +/* + * If enabled, frontswap_store will return failure even on success. As + * a result, the swap subsystem will always write the page to swap, in + * effect converting frontswap into a writethrough cache. In this mode, + * there is no direct reduction in swap writes, but a frontswap backend + * can unilaterally "reclaim" any pages in use with no data loss, thus + * providing increases control over maximum memory usage due to frontswap. + */ +static bool frontswap_writethrough_enabled __read_mostly; + +#ifdef CONFIG_DEBUG_FS +/* + * Counters available via /sys/kernel/debug/frontswap (if debugfs is + * properly configured). These are for information only so are not protected + * against increment races. + */ +static u64 frontswap_loads; +static u64 frontswap_succ_stores; +static u64 frontswap_failed_stores; +static u64 frontswap_invalidates; + +static inline void inc_frontswap_loads(void) { + frontswap_loads++; +} +static inline void inc_frontswap_succ_stores(void) { + frontswap_succ_stores++; +} +static inline void inc_frontswap_failed_stores(void) { + frontswap_failed_stores++; +} +static inline void inc_frontswap_invalidates(void) { + frontswap_invalidates++; +} +#else +static inline void inc_frontswap_loads(void) { } +static inline void inc_frontswap_succ_stores(void) { } +static inline void inc_frontswap_failed_stores(void) { } +static inline void inc_frontswap_invalidates(void) { } +#endif +/* + * Register operations for frontswap, returning previous thus allowing + * detection of multiple backends and possible nesting. + */ +struct frontswap_ops frontswap_register_ops(struct frontswap_ops *ops) +{ + struct frontswap_ops old = frontswap_ops; + + frontswap_ops = *ops; + frontswap_enabled = true; + return old; +} +EXPORT_SYMBOL(frontswap_register_ops); + +/* + * Enable/disable frontswap writethrough (see above). + */ +void frontswap_writethrough(bool enable) +{ + frontswap_writethrough_enabled = enable; +} +EXPORT_SYMBOL(frontswap_writethrough); + +/* + * Called when a swap device is swapon'd. + */ +void __frontswap_init(unsigned type) +{ + struct swap_info_struct *sis = swap_info[type]; + + BUG_ON(sis == NULL); + if (sis->frontswap_map == NULL) + return; + if (frontswap_enabled) + (*frontswap_ops.init)(type); +} +EXPORT_SYMBOL(__frontswap_init); + +/* + * "Store" data from a page to frontswap and associate it with the page's + * swaptype and offset. Page must be locked and in the swap cache. + * If frontswap already contains a page with matching swaptype and + * offset, the frontswap implmentation may either overwrite the data and + * return success or invalidate the page from frontswap and return failure. + */ +int __frontswap_store(struct page *page) +{ + int ret = -1, dup = 0; + swp_entry_t entry = { .val = page_private(page), }; + int type = swp_type(entry); + struct swap_info_struct *sis = swap_info[type]; + pgoff_t offset = swp_offset(entry); + + BUG_ON(!PageLocked(page)); + BUG_ON(sis == NULL); + if (frontswap_test(sis, offset)) + dup = 1; + ret = (*frontswap_ops.store)(type, offset, page); + if (ret == 0) { + frontswap_set(sis, offset); + inc_frontswap_succ_stores(); + if (!dup) + atomic_inc(&sis->frontswap_pages); + } else if (dup) { + /* + failed dup always results in automatic invalidate of + the (older) page from frontswap + */ + frontswap_clear(sis, offset); + atomic_dec(&sis->frontswap_pages); + inc_frontswap_failed_stores(); + } else + inc_frontswap_failed_stores(); + if (frontswap_writethrough_enabled) + /* report failure so swap also writes to swap device */ + ret = -1; + return ret; +} +EXPORT_SYMBOL(__frontswap_store); + +/* + * "Get" data from frontswap associated with swaptype and offset that were + * specified when the data was put to frontswap and use it to fill the + * specified page with data. Page must be locked and in the swap cache. + */ +int __frontswap_load(struct page *page) +{ + int ret = -1; + swp_entry_t entry = { .val = page_private(page), }; + int type = swp_type(entry); + struct swap_info_struct *sis = swap_info[type]; + pgoff_t offset = swp_offset(entry); + + BUG_ON(!PageLocked(page)); + BUG_ON(sis == NULL); + if (frontswap_test(sis, offset)) + ret = (*frontswap_ops.load)(type, offset, page); + if (ret == 0) + inc_frontswap_loads(); + return ret; +} +EXPORT_SYMBOL(__frontswap_load); + +/* + * Invalidate any data from frontswap associated with the specified swaptype + * and offset so that a subsequent "get" will fail. + */ +void __frontswap_invalidate_page(unsigned type, pgoff_t offset) +{ + struct swap_info_struct *sis = swap_info[type]; + + BUG_ON(sis == NULL); + if (frontswap_test(sis, offset)) { + (*frontswap_ops.invalidate_page)(type, offset); + atomic_dec(&sis->frontswap_pages); + frontswap_clear(sis, offset); + inc_frontswap_invalidates(); + } +} +EXPORT_SYMBOL(__frontswap_invalidate_page); + +/* + * Invalidate all data from frontswap associated with all offsets for the + * specified swaptype. + */ +void __frontswap_invalidate_area(unsigned type) +{ + struct swap_info_struct *sis = swap_info[type]; + + BUG_ON(sis == NULL); + if (sis->frontswap_map == NULL) + return; + (*frontswap_ops.invalidate_area)(type); + atomic_set(&sis->frontswap_pages, 0); + memset(sis->frontswap_map, 0, sis->max / sizeof(long)); +} +EXPORT_SYMBOL(__frontswap_invalidate_area); + +/* + * Frontswap, like a true swap device, may unnecessarily retain pages + * under certain circumstances; "shrink" frontswap is essentially a + * "partial swapoff" and works by calling try_to_unuse to attempt to + * unuse enough frontswap pages to attempt to -- subject to memory + * constraints -- reduce the number of pages in frontswap to the + * number given in the parameter target_pages. + */ +void frontswap_shrink(unsigned long target_pages) +{ + struct swap_info_struct *si = NULL; + int si_frontswap_pages; + unsigned long total_pages = 0, total_pages_to_unuse; + unsigned long pages = 0, pages_to_unuse = 0; + int type; + bool locked = false; + + /* + * we don't want to hold swap_lock while doing a very + * lengthy try_to_unuse, but swap_list may change + * so restart scan from swap_list.head each time + */ + spin_lock(&swap_lock); + locked = true; + total_pages = 0; + for (type = swap_list.head; type >= 0; type = si->next) { + si = swap_info[type]; + total_pages += atomic_read(&si->frontswap_pages); + } + if (total_pages <= target_pages) + goto out; + total_pages_to_unuse = total_pages - target_pages; + for (type = swap_list.head; type >= 0; type = si->next) { + si = swap_info[type]; + si_frontswap_pages = atomic_read(&si->frontswap_pages); + if (total_pages_to_unuse < si_frontswap_pages) + pages = pages_to_unuse = total_pages_to_unuse; + else { + pages = si_frontswap_pages; + pages_to_unuse = 0; /* unuse all */ + } + /* ensure there is enough RAM to fetch pages from frontswap */ + if (security_vm_enough_memory_mm(current->mm, pages)) + continue; + vm_unacct_memory(pages); + break; + } + if (type < 0) + goto out; + locked = false; + spin_unlock(&swap_lock); + try_to_unuse(type, true, pages_to_unuse); +out: + if (locked) + spin_unlock(&swap_lock); + return; +} +EXPORT_SYMBOL(frontswap_shrink); + +/* + * Count and return the number of frontswap pages across all + * swap devices. This is exported so that backend drivers can + * determine current usage without reading debugfs. + */ +unsigned long frontswap_curr_pages(void) +{ + int type; + unsigned long totalpages = 0; + struct swap_info_struct *si = NULL; + + spin_lock(&swap_lock); + for (type = swap_list.head; type >= 0; type = si->next) { + si = swap_info[type]; + totalpages += atomic_read(&si->frontswap_pages); + } + spin_unlock(&swap_lock); + return totalpages; +} +EXPORT_SYMBOL(frontswap_curr_pages); + +static int __init init_frontswap(void) +{ +#ifdef CONFIG_DEBUG_FS + struct dentry *root = debugfs_create_dir("frontswap", NULL); + if (root == NULL) + return -ENXIO; + debugfs_create_u64("loads", S_IRUGO, root, &frontswap_loads); + debugfs_create_u64("succ_stores", S_IRUGO, root, &frontswap_succ_stores); + debugfs_create_u64("failed_stores", S_IRUGO, root, + &frontswap_failed_stores); + debugfs_create_u64("invalidates", S_IRUGO, + root, &frontswap_invalidates); +#endif + return 0; +} + +module_init(init_frontswap); diff --git a/mm/memblock.c b/mm/memblock.c index 952123eba433..d4382095f8bd 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -184,7 +184,24 @@ static void __init_memblock memblock_remove_region(struct memblock_type *type, u } } -static int __init_memblock memblock_double_array(struct memblock_type *type) +/** + * memblock_double_array - double the size of the memblock regions array + * @type: memblock type of the regions array being doubled + * @new_area_start: starting address of memory range to avoid overlap with + * @new_area_size: size of memory range to avoid overlap with + * + * Double the size of the @type regions array. If memblock is being used to + * allocate memory for a new reserved regions array and there is a previously + * allocated memory range [@new_area_start,@new_area_start+@new_area_size] + * waiting to be reserved, ensure the memory used by the new array does + * not overlap. + * + * RETURNS: + * 0 on success, -1 on failure. + */ +static int __init_memblock memblock_double_array(struct memblock_type *type, + phys_addr_t new_area_start, + phys_addr_t new_area_size) { struct memblock_region *new_array, *old_array; phys_addr_t old_size, new_size, addr; @@ -222,7 +239,18 @@ static int __init_memblock memblock_double_array(struct memblock_type *type) new_array = kmalloc(new_size, GFP_KERNEL); addr = new_array ? __pa(new_array) : 0; } else { - addr = memblock_find_in_range(0, MEMBLOCK_ALLOC_ACCESSIBLE, new_size, sizeof(phys_addr_t)); + /* only exclude range when trying to double reserved.regions */ + if (type != &memblock.reserved) + new_area_start = new_area_size = 0; + + addr = memblock_find_in_range(new_area_start + new_area_size, + memblock.current_limit, + new_size, sizeof(phys_addr_t)); + if (!addr && new_area_size) + addr = memblock_find_in_range(0, + min(new_area_start, memblock.current_limit), + new_size, sizeof(phys_addr_t)); + new_array = addr ? __va(addr) : 0; } if (!addr) { @@ -399,7 +427,7 @@ repeat: */ if (!insert) { while (type->cnt + nr_new > type->max) - if (memblock_double_array(type) < 0) + if (memblock_double_array(type, obase, size) < 0) return -ENOMEM; insert = true; goto repeat; @@ -450,7 +478,7 @@ static int __init_memblock memblock_isolate_range(struct memblock_type *type, /* we'll create at most two more regions */ while (type->cnt + 2 > type->max) - if (memblock_double_array(type) < 0) + if (memblock_double_array(type, base, size) < 0) return -ENOMEM; for (i = 0; i < type->cnt; i++) { @@ -540,9 +568,9 @@ int __init_memblock memblock_reserve(phys_addr_t base, phys_addr_t size) * __next_free_mem_range - next function for for_each_free_mem_range() * @idx: pointer to u64 loop variable * @nid: nid: node selector, %MAX_NUMNODES for all nodes - * @p_start: ptr to phys_addr_t for start address of the range, can be %NULL - * @p_end: ptr to phys_addr_t for end address of the range, can be %NULL - * @p_nid: ptr to int for nid of the range, can be %NULL + * @out_start: ptr to phys_addr_t for start address of the range, can be %NULL + * @out_end: ptr to phys_addr_t for end address of the range, can be %NULL + * @out_nid: ptr to int for nid of the range, can be %NULL * * Find the first free area from *@idx which matches @nid, fill the out * parameters, and update *@idx for the next iteration. The lower 32bit of @@ -616,9 +644,9 @@ void __init_memblock __next_free_mem_range(u64 *idx, int nid, * __next_free_mem_range_rev - next function for for_each_free_mem_range_reverse() * @idx: pointer to u64 loop variable * @nid: nid: node selector, %MAX_NUMNODES for all nodes - * @p_start: ptr to phys_addr_t for start address of the range, can be %NULL - * @p_end: ptr to phys_addr_t for end address of the range, can be %NULL - * @p_nid: ptr to int for nid of the range, can be %NULL + * @out_start: ptr to phys_addr_t for start address of the range, can be %NULL + * @out_end: ptr to phys_addr_t for end address of the range, can be %NULL + * @out_nid: ptr to int for nid of the range, can be %NULL * * Reverse of __next_free_mem_range(). */ @@ -867,6 +895,16 @@ int __init_memblock memblock_is_memory(phys_addr_t addr) return memblock_search(&memblock.memory, addr) != -1; } +/** + * memblock_is_region_memory - check if a region is a subset of memory + * @base: base of region to check + * @size: size of region to check + * + * Check if the region [@base, @base+@size) is a subset of a memory block. + * + * RETURNS: + * 0 if false, non-zero if true + */ int __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size) { int idx = memblock_search(&memblock.memory, base); @@ -879,6 +917,16 @@ int __init_memblock memblock_is_region_memory(phys_addr_t base, phys_addr_t size memblock.memory.regions[idx].size) >= end; } +/** + * memblock_is_region_reserved - check if a region intersects reserved memory + * @base: base of region to check + * @size: size of region to check + * + * Check if the region [@base, @base+@size) intersects a reserved memory block. + * + * RETURNS: + * 0 if false, non-zero if true + */ int __init_memblock memblock_is_region_reserved(phys_addr_t base, phys_addr_t size) { memblock_cap_size(base, &size); diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ac35bccadb7b..f72b5e52451a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1148,7 +1148,7 @@ bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, { if (root_memcg == memcg) return true; - if (!root_memcg->use_hierarchy) + if (!root_memcg->use_hierarchy || !memcg) return false; return css_is_ancestor(&memcg->css, &root_memcg->css); } @@ -1234,7 +1234,7 @@ int mem_cgroup_inactive_file_is_low(struct lruvec *lruvec) /** * mem_cgroup_margin - calculate chargeable space of a memory cgroup - * @mem: the memory cgroup + * @memcg: the memory cgroup * * Returns the maximum amount of memory @mem can be charged with, in * pages. @@ -1508,7 +1508,7 @@ static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg, /** * test_mem_cgroup_node_reclaimable - * @mem: the target memcg + * @memcg: the target memcg * @nid: the node ID to be checked. * @noswap : specify true here if the user wants flle only information. * diff --git a/mm/memory.c b/mm/memory.c index 1b7dc662bf9f..2466d1250231 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1225,7 +1225,15 @@ static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, next = pmd_addr_end(addr, end); if (pmd_trans_huge(*pmd)) { if (next - addr != HPAGE_PMD_SIZE) { - VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem)); +#ifdef CONFIG_DEBUG_VM + if (!rwsem_is_locked(&tlb->mm->mmap_sem)) { + pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n", + __func__, addr, end, + vma->vm_start, + vma->vm_end); + BUG(); + } +#endif split_huge_page_pmd(vma->vm_mm, pmd); } else if (zap_huge_pmd(tlb, vma, pmd, addr)) goto next; @@ -1366,7 +1374,7 @@ void unmap_vmas(struct mmu_gather *tlb, /** * zap_page_range - remove user pages in a given range * @vma: vm_area_struct holding the applicable pages - * @address: starting address of pages to zap + * @start: starting address of pages to zap * @size: number of bytes to zap * @details: details of nonlinear truncation or shared cache invalidation * diff --git a/mm/mempolicy.c b/mm/mempolicy.c index f15c1b24ca18..1d771e4200d2 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1177,7 +1177,7 @@ static long do_mbind(unsigned long start, unsigned long len, if (!list_empty(&pagelist)) { nr_failed = migrate_pages(&pagelist, new_vma_page, (unsigned long)vma, - false, true); + false, MIGRATE_SYNC); if (nr_failed) putback_lru_pages(&pagelist); } diff --git a/mm/nommu.c b/mm/nommu.c index c4acfbc09972..d4b0c10872de 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1486,7 +1486,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); - ret = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); + retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); if (file) fput(file); diff --git a/mm/oom_kill.c b/mm/oom_kill.c index ed0e19677360..ac300c99baf6 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -183,7 +183,8 @@ static bool oom_unkillable_task(struct task_struct *p, unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, const nodemask_t *nodemask, unsigned long totalpages) { - unsigned long points; + long points; + long adj; if (oom_unkillable_task(p, memcg, nodemask)) return 0; @@ -192,7 +193,8 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, if (!p) return 0; - if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { + adj = p->signal->oom_score_adj; + if (adj == OOM_SCORE_ADJ_MIN) { task_unlock(p); return 0; } @@ -210,20 +212,17 @@ unsigned long oom_badness(struct task_struct *p, struct mem_cgroup *memcg, * implementation used by LSMs. */ if (has_capability_noaudit(p, CAP_SYS_ADMIN)) - points -= 30 * totalpages / 1000; + adj -= 30; - /* - * /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may - * either completely disable oom killing or always prefer a certain - * task. - */ - points += p->signal->oom_score_adj * totalpages / 1000; + /* Normalize to oom_score_adj units */ + adj *= totalpages / 1000; + points += adj; /* * Never return 0 for an eligible task regardless of the root bonus and * oom_score_adj (oom_score_adj can't be OOM_SCORE_ADJ_MIN here). */ - return points ? points : 1; + return points > 0 ? points : 1; } /* @@ -366,7 +365,7 @@ static struct task_struct *select_bad_process(unsigned int *ppoints, /** * dump_tasks - dump current memory state of all system tasks - * @mem: current's memory controller, if constrained + * @memcg: current's memory controller, if constrained * @nodemask: nodemask passed to page allocator for mempolicy ooms * * Dumps the current memory state of all eligible tasks. Tasks not in the same diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c index 1ccbd714059c..eb750f851395 100644 --- a/mm/page_cgroup.c +++ b/mm/page_cgroup.c @@ -392,7 +392,7 @@ static struct swap_cgroup *lookup_swap_cgroup(swp_entry_t ent, /** * swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry. - * @end: swap entry to be cmpxchged + * @ent: swap entry to be cmpxchged * @old: old id * @new: new id * @@ -422,7 +422,7 @@ unsigned short swap_cgroup_cmpxchg(swp_entry_t ent, /** * swap_cgroup_record - record mem_cgroup for this swp_entry. * @ent: swap entry to be recorded into - * @mem: mem_cgroup to be recorded + * @id: mem_cgroup to be recorded * * Returns old value at success, 0 at failure. * (Of course, old value can be 0.) diff --git a/mm/page_io.c b/mm/page_io.c index dc76b4d0611e..34f02923744c 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -18,6 +18,7 @@ #include <linux/bio.h> #include <linux/swapops.h> #include <linux/writeback.h> +#include <linux/frontswap.h> #include <asm/pgtable.h> static struct bio *get_swap_bio(gfp_t gfp_flags, @@ -98,6 +99,12 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) unlock_page(page); goto out; } + if (frontswap_store(page) == 0) { + set_page_writeback(page); + unlock_page(page); + end_page_writeback(page); + goto out; + } bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write); if (bio == NULL) { set_page_dirty(page); @@ -122,6 +129,11 @@ int swap_readpage(struct page *page) VM_BUG_ON(!PageLocked(page)); VM_BUG_ON(PageUptodate(page)); + if (frontswap_load(page) == 0) { + SetPageUptodate(page); + unlock_page(page); + goto out; + } bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read); if (bio == NULL) { unlock_page(page); diff --git a/mm/pagewalk.c b/mm/pagewalk.c index aa9701e12714..6c118d012bb5 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -162,7 +162,6 @@ static int walk_hugetlb_range(struct vm_area_struct *vma, /** * walk_page_range - walk a memory map's page tables with a callback - * @mm: memory map to walk * @addr: starting address * @end: ending address * @walk: set of callbacks to invoke for each level of the tree diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c index 405d331804c3..3707c71ae4cd 100644 --- a/mm/percpu-vm.c +++ b/mm/percpu-vm.c @@ -360,7 +360,6 @@ err_free: * @chunk: chunk to depopulate * @off: offset to the area to depopulate * @size: size of the area to depopulate in bytes - * @flush: whether to flush cache and tlb or not * * For each cpu, depopulate and unmap pages [@page_start,@page_end) * from @chunk. If @flush is true, vcache is flushed before unmapping diff --git a/mm/shmem.c b/mm/shmem.c index c244e93a70fa..4ce02e0673db 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -683,10 +683,21 @@ static int shmem_unuse_inode(struct shmem_inode_info *info, mutex_lock(&shmem_swaplist_mutex); /* * We needed to drop mutex to make that restrictive page - * allocation; but the inode might already be freed by now, - * and we cannot refer to inode or mapping or info to check. - * However, we do hold page lock on the PageSwapCache page, - * so can check if that still has our reference remaining. + * allocation, but the inode might have been freed while we + * dropped it: although a racing shmem_evict_inode() cannot + * complete without emptying the radix_tree, our page lock + * on this swapcache page is not enough to prevent that - + * free_swap_and_cache() of our swap entry will only + * trylock_page(), removing swap from radix_tree whatever. + * + * We must not proceed to shmem_add_to_page_cache() if the + * inode has been freed, but of course we cannot rely on + * inode or mapping or info to check that. However, we can + * safely check if our swap entry is still in use (and here + * it can't have got reused for another page): if it's still + * in use, then the inode cannot have been freed yet, and we + * can safely proceed (if it's no longer in use, that tells + * nothing about the inode, but we don't need to unuse swap). */ if (!page_swapcount(*pagep)) error = -ENOENT; @@ -730,9 +741,9 @@ int shmem_unuse(swp_entry_t swap, struct page *page) /* * There's a faint possibility that swap page was replaced before - * caller locked it: it will come back later with the right page. + * caller locked it: caller will come back later with the right page. */ - if (unlikely(!PageSwapCache(page))) + if (unlikely(!PageSwapCache(page) || page_private(page) != swap.val)) goto out; /* @@ -995,21 +1006,15 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp, newpage = shmem_alloc_page(gfp, info, index); if (!newpage) return -ENOMEM; - VM_BUG_ON(shmem_should_replace_page(newpage, gfp)); - *pagep = newpage; page_cache_get(newpage); copy_highpage(newpage, oldpage); + flush_dcache_page(newpage); - VM_BUG_ON(!PageLocked(oldpage)); __set_page_locked(newpage); - VM_BUG_ON(!PageUptodate(oldpage)); SetPageUptodate(newpage); - VM_BUG_ON(!PageSwapBacked(oldpage)); SetPageSwapBacked(newpage); - VM_BUG_ON(!swap_index); set_page_private(newpage, swap_index); - VM_BUG_ON(!PageSwapCache(oldpage)); SetPageSwapCache(newpage); /* @@ -1019,13 +1024,24 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp, spin_lock_irq(&swap_mapping->tree_lock); error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage, newpage); - __inc_zone_page_state(newpage, NR_FILE_PAGES); - __dec_zone_page_state(oldpage, NR_FILE_PAGES); + if (!error) { + __inc_zone_page_state(newpage, NR_FILE_PAGES); + __dec_zone_page_state(oldpage, NR_FILE_PAGES); + } spin_unlock_irq(&swap_mapping->tree_lock); - BUG_ON(error); - mem_cgroup_replace_page_cache(oldpage, newpage); - lru_cache_add_anon(newpage); + if (unlikely(error)) { + /* + * Is this possible? I think not, now that our callers check + * both PageSwapCache and page_private after getting page lock; + * but be defensive. Reverse old to newpage for clear and free. + */ + oldpage = newpage; + } else { + mem_cgroup_replace_page_cache(oldpage, newpage); + lru_cache_add_anon(newpage); + *pagep = newpage; + } ClearPageSwapCache(oldpage); set_page_private(oldpage, 0); @@ -1033,7 +1049,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp, unlock_page(oldpage); page_cache_release(oldpage); page_cache_release(oldpage); - return 0; + return error; } /* @@ -1107,7 +1123,8 @@ repeat: /* We have to do this with page locked to prevent races */ lock_page(page); - if (!PageSwapCache(page) || page->mapping) { + if (!PageSwapCache(page) || page_private(page) != swap.val || + page->mapping) { error = -EEXIST; /* try again */ goto failed; } diff --git a/mm/swapfile.c b/mm/swapfile.c index 457b10baef59..71373d03fcee 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -31,6 +31,8 @@ #include <linux/memcontrol.h> #include <linux/poll.h> #include <linux/oom.h> +#include <linux/frontswap.h> +#include <linux/swapfile.h> #include <asm/pgtable.h> #include <asm/tlbflush.h> @@ -42,7 +44,7 @@ static bool swap_count_continued(struct swap_info_struct *, pgoff_t, static void free_swap_count_continuations(struct swap_info_struct *); static sector_t map_swap_entry(swp_entry_t, struct block_device**); -static DEFINE_SPINLOCK(swap_lock); +DEFINE_SPINLOCK(swap_lock); static unsigned int nr_swapfiles; long nr_swap_pages; long total_swap_pages; @@ -53,9 +55,9 @@ static const char Unused_file[] = "Unused swap file entry "; static const char Bad_offset[] = "Bad swap offset entry "; static const char Unused_offset[] = "Unused swap offset entry "; -static struct swap_list_t swap_list = {-1, -1}; +struct swap_list_t swap_list = {-1, -1}; -static struct swap_info_struct *swap_info[MAX_SWAPFILES]; +struct swap_info_struct *swap_info[MAX_SWAPFILES]; static DEFINE_MUTEX(swapon_mutex); @@ -556,6 +558,7 @@ static unsigned char swap_entry_free(struct swap_info_struct *p, swap_list.next = p->type; nr_swap_pages++; p->inuse_pages--; + frontswap_invalidate_page(p->type, offset); if ((p->flags & SWP_BLKDEV) && disk->fops->swap_slot_free_notify) disk->fops->swap_slot_free_notify(p->bdev, offset); @@ -985,11 +988,12 @@ static int unuse_mm(struct mm_struct *mm, } /* - * Scan swap_map from current position to next entry still in use. + * Scan swap_map (or frontswap_map if frontswap parameter is true) + * from current position to next entry still in use. * Recycle to start on reaching the end, returning 0 when empty. */ static unsigned int find_next_to_unuse(struct swap_info_struct *si, - unsigned int prev) + unsigned int prev, bool frontswap) { unsigned int max = si->max; unsigned int i = prev; @@ -1015,6 +1019,12 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si, prev = 0; i = 1; } + if (frontswap) { + if (frontswap_test(si, i)) + break; + else + continue; + } count = si->swap_map[i]; if (count && swap_count(count) != SWAP_MAP_BAD) break; @@ -1026,8 +1036,12 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si, * We completely avoid races by reading each swap page in advance, * and then search for the process using it. All the necessary * page table adjustments can then be made atomically. + * + * if the boolean frontswap is true, only unuse pages_to_unuse pages; + * pages_to_unuse==0 means all pages; ignored if frontswap is false */ -static int try_to_unuse(unsigned int type) +int try_to_unuse(unsigned int type, bool frontswap, + unsigned long pages_to_unuse) { struct swap_info_struct *si = swap_info[type]; struct mm_struct *start_mm; @@ -1060,7 +1074,7 @@ static int try_to_unuse(unsigned int type) * one pass through swap_map is enough, but not necessarily: * there are races when an instance of an entry might be missed. */ - while ((i = find_next_to_unuse(si, i)) != 0) { + while ((i = find_next_to_unuse(si, i, frontswap)) != 0) { if (signal_pending(current)) { retval = -EINTR; break; @@ -1227,6 +1241,10 @@ static int try_to_unuse(unsigned int type) * interactive performance. */ cond_resched(); + if (frontswap && pages_to_unuse > 0) { + if (!--pages_to_unuse) + break; + } } mmput(start_mm); @@ -1486,7 +1504,8 @@ bad_bmap: } static void enable_swap_info(struct swap_info_struct *p, int prio, - unsigned char *swap_map) + unsigned char *swap_map, + unsigned long *frontswap_map) { int i, prev; @@ -1496,6 +1515,7 @@ static void enable_swap_info(struct swap_info_struct *p, int prio, else p->prio = --least_priority; p->swap_map = swap_map; + frontswap_map_set(p, frontswap_map); p->flags |= SWP_WRITEOK; nr_swap_pages += p->pages; total_swap_pages += p->pages; @@ -1512,6 +1532,7 @@ static void enable_swap_info(struct swap_info_struct *p, int prio, swap_list.head = swap_list.next = p->type; else swap_info[prev]->next = p->type; + frontswap_init(p->type); spin_unlock(&swap_lock); } @@ -1585,7 +1606,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) spin_unlock(&swap_lock); oom_score_adj = test_set_oom_score_adj(OOM_SCORE_ADJ_MAX); - err = try_to_unuse(type); + err = try_to_unuse(type, false, 0); /* force all pages to be unused */ compare_swap_oom_score_adj(OOM_SCORE_ADJ_MAX, oom_score_adj); if (err) { @@ -1596,7 +1617,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) * sys_swapoff for this swap_info_struct at this point. */ /* re-insert swap space back into swap_list */ - enable_swap_info(p, p->prio, p->swap_map); + enable_swap_info(p, p->prio, p->swap_map, frontswap_map_get(p)); goto out_dput; } @@ -1622,9 +1643,11 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile) swap_map = p->swap_map; p->swap_map = NULL; p->flags = 0; + frontswap_invalidate_area(type); spin_unlock(&swap_lock); mutex_unlock(&swapon_mutex); vfree(swap_map); + vfree(frontswap_map_get(p)); /* Destroy swap account informatin */ swap_cgroup_swapoff(type); @@ -1893,24 +1916,20 @@ static unsigned long read_swap_header(struct swap_info_struct *p, /* * Find out how many pages are allowed for a single swap - * device. There are three limiting factors: 1) the number + * device. There are two limiting factors: 1) the number * of bits for the swap offset in the swp_entry_t type, and * 2) the number of bits in the swap pte as defined by the - * the different architectures, and 3) the number of free bits - * in an exceptional radix_tree entry. In order to find the + * different architectures. In order to find the * largest possible bit mask, a swap entry with swap type 0 * and swap offset ~0UL is created, encoded to a swap pte, * decoded to a swp_entry_t again, and finally the swap * offset is extracted. This will mask all the bits from * the initial ~0UL mask that can't be encoded in either * the swp_entry_t or the architecture definition of a - * swap pte. Then the same is done for a radix_tree entry. + * swap pte. */ maxpages = swp_offset(pte_to_swp_entry( - swp_entry_to_pte(swp_entry(0, ~0UL)))); - maxpages = swp_offset(radix_to_swp_entry( - swp_to_radix_entry(swp_entry(0, maxpages)))) + 1; - + swp_entry_to_pte(swp_entry(0, ~0UL)))) + 1; if (maxpages > swap_header->info.last_page) { maxpages = swap_header->info.last_page + 1; /* p->max is an unsigned int: don't overflow it */ @@ -1988,6 +2007,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) sector_t span; unsigned long maxpages; unsigned char *swap_map = NULL; + unsigned long *frontswap_map = NULL; struct page *page = NULL; struct inode *inode = NULL; @@ -2071,6 +2091,9 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) error = nr_extents; goto bad_swap; } + /* frontswap enabled? set up bit-per-page map for frontswap */ + if (frontswap_enabled) + frontswap_map = vzalloc(maxpages / sizeof(long)); if (p->bdev) { if (blk_queue_nonrot(bdev_get_queue(p->bdev))) { @@ -2086,14 +2109,15 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) if (swap_flags & SWAP_FLAG_PREFER) prio = (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT; - enable_swap_info(p, prio, swap_map); + enable_swap_info(p, prio, swap_map, frontswap_map); printk(KERN_INFO "Adding %uk swap on %s. " - "Priority:%d extents:%d across:%lluk %s%s\n", + "Priority:%d extents:%d across:%lluk %s%s%s\n", p->pages<<(PAGE_SHIFT-10), name, p->prio, nr_extents, (unsigned long long)span<<(PAGE_SHIFT-10), (p->flags & SWP_SOLIDSTATE) ? "SS" : "", - (p->flags & SWP_DISCARDABLE) ? "D" : ""); + (p->flags & SWP_DISCARDABLE) ? "D" : "", + (frontswap_map) ? "FS" : ""); mutex_unlock(&swapon_mutex); atomic_inc(&proc_poll_event); |