diff options
Diffstat (limited to 'mm')
46 files changed, 1598 insertions, 1173 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 7ba8feae11b8..dd8e2aafb07e 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -318,7 +318,7 @@ static void wakeup_timer_fn(unsigned long data) if (bdi->wb.task) { trace_writeback_wake_thread(bdi); wake_up_process(bdi->wb.task); - } else { + } else if (bdi->dev) { /* * When bdi tasks are inactive for long time, they are killed. * In this case we have to wake-up the forker thread which @@ -584,6 +584,8 @@ EXPORT_SYMBOL(bdi_register_dev); */ static void bdi_wb_shutdown(struct backing_dev_info *bdi) { + struct task_struct *task; + if (!bdi_cap_writeback_dirty(bdi)) return; @@ -602,8 +604,13 @@ static void bdi_wb_shutdown(struct backing_dev_info *bdi) * Finally, kill the kernel thread. We don't need to be RCU * safe anymore, since the bdi is gone from visibility. */ - if (bdi->wb.task) - kthread_stop(bdi->wb.task); + spin_lock_bh(&bdi->wb_lock); + task = bdi->wb.task; + bdi->wb.task = NULL; + spin_unlock_bh(&bdi->wb_lock); + + if (task) + kthread_stop(task); } /* @@ -623,7 +630,9 @@ static void bdi_prune_sb(struct backing_dev_info *bdi) void bdi_unregister(struct backing_dev_info *bdi) { - if (bdi->dev) { + struct device *dev = bdi->dev; + + if (dev) { bdi_set_min_ratio(bdi, 0); trace_writeback_bdi_unregister(bdi); bdi_prune_sb(bdi); @@ -632,8 +641,12 @@ void bdi_unregister(struct backing_dev_info *bdi) if (!bdi_cap_flush_forker(bdi)) bdi_wb_shutdown(bdi); bdi_debug_unregister(bdi); - device_unregister(bdi->dev); + + spin_lock_bh(&bdi->wb_lock); bdi->dev = NULL; + spin_unlock_bh(&bdi->wb_lock); + + device_unregister(dev); } } EXPORT_SYMBOL(bdi_unregister); diff --git a/mm/bootmem.c b/mm/bootmem.c index 668e94df8cf2..0131170c9d54 100644 --- a/mm/bootmem.c +++ b/mm/bootmem.c @@ -766,14 +766,13 @@ void * __init alloc_bootmem_section(unsigned long size, unsigned long section_nr) { bootmem_data_t *bdata; - unsigned long pfn, goal, limit; + unsigned long pfn, goal; pfn = section_nr_to_pfn(section_nr); goal = pfn << PAGE_SHIFT; - limit = section_nr_to_pfn(section_nr + 1) << PAGE_SHIFT; bdata = &bootmem_node_data[early_pfn_to_nid(pfn)]; - return alloc_bootmem_core(bdata, size, SMP_CACHE_BYTES, goal, limit); + return alloc_bootmem_core(bdata, size, SMP_CACHE_BYTES, goal, 0); } #endif diff --git a/mm/bounce.c b/mm/bounce.c index 4e9ae722af83..d1be02ca1889 100644 --- a/mm/bounce.c +++ b/mm/bounce.c @@ -50,9 +50,9 @@ static void bounce_copy_vec(struct bio_vec *to, unsigned char *vfrom) unsigned char *vto; local_irq_save(flags); - vto = kmap_atomic(to->bv_page, KM_BOUNCE_READ); + vto = kmap_atomic(to->bv_page); memcpy(vto + to->bv_offset, vfrom, to->bv_len); - kunmap_atomic(vto, KM_BOUNCE_READ); + kunmap_atomic(vto); local_irq_restore(flags); } diff --git a/mm/cleancache.c b/mm/cleancache.c index bcaae4c2a770..5646c740f613 100644 --- a/mm/cleancache.c +++ b/mm/cleancache.c @@ -15,29 +15,34 @@ #include <linux/fs.h> #include <linux/exportfs.h> #include <linux/mm.h> +#include <linux/debugfs.h> #include <linux/cleancache.h> /* * This global enablement flag may be read thousands of times per second - * by cleancache_get/put/flush even on systems where cleancache_ops + * by cleancache_get/put/invalidate even on systems where cleancache_ops * is not claimed (e.g. cleancache is config'ed on but remains * disabled), so is preferred to the slower alternative: a function * call that checks a non-global. */ -int cleancache_enabled; +int cleancache_enabled __read_mostly; EXPORT_SYMBOL(cleancache_enabled); /* * cleancache_ops is set by cleancache_ops_register to contain the pointers * to the cleancache "backend" implementation functions. */ -static struct cleancache_ops cleancache_ops; +static struct cleancache_ops cleancache_ops __read_mostly; -/* useful stats available in /sys/kernel/mm/cleancache */ -static unsigned long cleancache_succ_gets; -static unsigned long cleancache_failed_gets; -static unsigned long cleancache_puts; -static unsigned long cleancache_flushes; +/* + * 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 cleancache_succ_gets; +static u64 cleancache_failed_gets; +static u64 cleancache_puts; +static u64 cleancache_invalidates; /* * register operations for cleancache, returning previous thus allowing @@ -148,10 +153,11 @@ void __cleancache_put_page(struct page *page) EXPORT_SYMBOL(__cleancache_put_page); /* - * Flush any data from cleancache associated with the poolid and the + * Invalidate any data from cleancache associated with the poolid and the * page's inode and page index so that a subsequent "get" will fail. */ -void __cleancache_flush_page(struct address_space *mapping, struct page *page) +void __cleancache_invalidate_page(struct address_space *mapping, + struct page *page) { /* careful... page->mapping is NULL sometimes when this is called */ int pool_id = mapping->host->i_sb->cleancache_poolid; @@ -160,85 +166,57 @@ void __cleancache_flush_page(struct address_space *mapping, struct page *page) if (pool_id >= 0) { VM_BUG_ON(!PageLocked(page)); if (cleancache_get_key(mapping->host, &key) >= 0) { - (*cleancache_ops.flush_page)(pool_id, key, page->index); - cleancache_flushes++; + (*cleancache_ops.invalidate_page)(pool_id, + key, page->index); + cleancache_invalidates++; } } } -EXPORT_SYMBOL(__cleancache_flush_page); +EXPORT_SYMBOL(__cleancache_invalidate_page); /* - * Flush all data from cleancache associated with the poolid and the + * Invalidate all data from cleancache associated with the poolid and the * mappings's inode so that all subsequent gets to this poolid/inode * will fail. */ -void __cleancache_flush_inode(struct address_space *mapping) +void __cleancache_invalidate_inode(struct address_space *mapping) { int pool_id = mapping->host->i_sb->cleancache_poolid; struct cleancache_filekey key = { .u.key = { 0 } }; if (pool_id >= 0 && cleancache_get_key(mapping->host, &key) >= 0) - (*cleancache_ops.flush_inode)(pool_id, key); + (*cleancache_ops.invalidate_inode)(pool_id, key); } -EXPORT_SYMBOL(__cleancache_flush_inode); +EXPORT_SYMBOL(__cleancache_invalidate_inode); /* * Called by any cleancache-enabled filesystem at time of unmount; * note that pool_id is surrendered and may be reutrned by a subsequent * cleancache_init_fs or cleancache_init_shared_fs */ -void __cleancache_flush_fs(struct super_block *sb) +void __cleancache_invalidate_fs(struct super_block *sb) { if (sb->cleancache_poolid >= 0) { int old_poolid = sb->cleancache_poolid; sb->cleancache_poolid = -1; - (*cleancache_ops.flush_fs)(old_poolid); + (*cleancache_ops.invalidate_fs)(old_poolid); } } -EXPORT_SYMBOL(__cleancache_flush_fs); - -#ifdef CONFIG_SYSFS - -/* see Documentation/ABI/xxx/sysfs-kernel-mm-cleancache */ - -#define CLEANCACHE_SYSFS_RO(_name) \ - static ssize_t cleancache_##_name##_show(struct kobject *kobj, \ - struct kobj_attribute *attr, char *buf) \ - { \ - return sprintf(buf, "%lu\n", cleancache_##_name); \ - } \ - static struct kobj_attribute cleancache_##_name##_attr = { \ - .attr = { .name = __stringify(_name), .mode = 0444 }, \ - .show = cleancache_##_name##_show, \ - } - -CLEANCACHE_SYSFS_RO(succ_gets); -CLEANCACHE_SYSFS_RO(failed_gets); -CLEANCACHE_SYSFS_RO(puts); -CLEANCACHE_SYSFS_RO(flushes); - -static struct attribute *cleancache_attrs[] = { - &cleancache_succ_gets_attr.attr, - &cleancache_failed_gets_attr.attr, - &cleancache_puts_attr.attr, - &cleancache_flushes_attr.attr, - NULL, -}; - -static struct attribute_group cleancache_attr_group = { - .attrs = cleancache_attrs, - .name = "cleancache", -}; - -#endif /* CONFIG_SYSFS */ +EXPORT_SYMBOL(__cleancache_invalidate_fs); static int __init init_cleancache(void) { -#ifdef CONFIG_SYSFS - int err; - - err = sysfs_create_group(mm_kobj, &cleancache_attr_group); -#endif /* CONFIG_SYSFS */ +#ifdef CONFIG_DEBUG_FS + struct dentry *root = debugfs_create_dir("cleancache", NULL); + if (root == NULL) + return -ENXIO; + debugfs_create_u64("succ_gets", S_IRUGO, root, &cleancache_succ_gets); + debugfs_create_u64("failed_gets", S_IRUGO, + root, &cleancache_failed_gets); + debugfs_create_u64("puts", S_IRUGO, root, &cleancache_puts); + debugfs_create_u64("invalidates", S_IRUGO, + root, &cleancache_invalidates); +#endif return 0; } module_init(init_cleancache) diff --git a/mm/compaction.c b/mm/compaction.c index 71a58f67f481..74a8c825ff28 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -35,7 +35,7 @@ struct compact_control { unsigned long migrate_pfn; /* isolate_migratepages search base */ bool sync; /* Synchronous migration */ - unsigned int order; /* order a direct compactor needs */ + int order; /* order a direct compactor needs */ int migratetype; /* MOVABLE, RECLAIMABLE etc */ struct zone *zone; }; @@ -313,12 +313,34 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, } else if (!locked) spin_lock_irq(&zone->lru_lock); + /* + * migrate_pfn does not necessarily start aligned to a + * pageblock. Ensure that pfn_valid is called when moving + * into a new MAX_ORDER_NR_PAGES range in case of large + * memory holes within the zone + */ + if ((low_pfn & (MAX_ORDER_NR_PAGES - 1)) == 0) { + if (!pfn_valid(low_pfn)) { + low_pfn += MAX_ORDER_NR_PAGES - 1; + continue; + } + } + if (!pfn_valid_within(low_pfn)) continue; nr_scanned++; - /* Get the page and skip if free */ + /* + * Get the page and ensure the page is within the same zone. + * See the comment in isolate_freepages about overlapping + * nodes. It is deliberate that the new zone lock is not taken + * as memory compaction should not move pages between nodes. + */ page = pfn_to_page(low_pfn); + if (page_zone(page) != zone) + continue; + + /* Skip if free */ if (PageBuddy(page)) continue; @@ -653,49 +675,71 @@ unsigned long try_to_compact_pages(struct zonelist *zonelist, /* Compact all zones within a node */ -static int compact_node(int nid) +static int __compact_pgdat(pg_data_t *pgdat, struct compact_control *cc) { int zoneid; - pg_data_t *pgdat; struct zone *zone; - if (nid < 0 || nid >= nr_node_ids || !node_online(nid)) - return -EINVAL; - pgdat = NODE_DATA(nid); - - /* Flush pending updates to the LRU lists */ - lru_add_drain_all(); - for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { - struct compact_control cc = { - .nr_freepages = 0, - .nr_migratepages = 0, - .order = -1, - .sync = true, - }; zone = &pgdat->node_zones[zoneid]; if (!populated_zone(zone)) continue; - cc.zone = zone; - INIT_LIST_HEAD(&cc.freepages); - INIT_LIST_HEAD(&cc.migratepages); - - compact_zone(zone, &cc); + cc->nr_freepages = 0; + cc->nr_migratepages = 0; + cc->zone = zone; + INIT_LIST_HEAD(&cc->freepages); + INIT_LIST_HEAD(&cc->migratepages); + + if (cc->order == -1 || !compaction_deferred(zone, cc->order)) + compact_zone(zone, cc); + + if (cc->order > 0) { + int ok = zone_watermark_ok(zone, cc->order, + low_wmark_pages(zone), 0, 0); + if (ok && cc->order > zone->compact_order_failed) + zone->compact_order_failed = cc->order + 1; + /* Currently async compaction is never deferred. */ + else if (!ok && cc->sync) + defer_compaction(zone, cc->order); + } - VM_BUG_ON(!list_empty(&cc.freepages)); - VM_BUG_ON(!list_empty(&cc.migratepages)); + VM_BUG_ON(!list_empty(&cc->freepages)); + VM_BUG_ON(!list_empty(&cc->migratepages)); } return 0; } +int compact_pgdat(pg_data_t *pgdat, int order) +{ + struct compact_control cc = { + .order = order, + .sync = false, + }; + + return __compact_pgdat(pgdat, &cc); +} + +static int compact_node(int nid) +{ + struct compact_control cc = { + .order = -1, + .sync = true, + }; + + return __compact_pgdat(NODE_DATA(nid), &cc); +} + /* Compact all nodes in the system */ static int compact_nodes(void) { int nid; + /* Flush pending updates to the LRU lists */ + lru_add_drain_all(); + for_each_online_node(nid) compact_node(nid); @@ -728,7 +772,14 @@ ssize_t sysfs_compact_node(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { - compact_node(dev->id); + int nid = dev->id; + + if (nid >= 0 && nid < nr_node_ids && node_online(nid)) { + /* Flush pending updates to the LRU lists */ + lru_add_drain_all(); + + compact_node(nid); + } return count; } diff --git a/mm/filemap.c b/mm/filemap.c index 97f49ed35bd2..c3811bc6b9e3 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -101,9 +101,8 @@ * ->inode->i_lock (zap_pte_range->set_page_dirty) * ->private_lock (zap_pte_range->__set_page_dirty_buffers) * - * (code doesn't rely on that order, so you could switch it around) - * ->tasklist_lock (memory_failure, collect_procs_ao) - * ->i_mmap_mutex + * ->i_mmap_mutex + * ->tasklist_lock (memory_failure, collect_procs_ao) */ /* @@ -123,7 +122,7 @@ void __delete_from_page_cache(struct page *page) if (PageUptodate(page) && PageMappedToDisk(page)) cleancache_put_page(page); else - cleancache_flush_page(mapping, page); + cleancache_invalidate_page(mapping, page); radix_tree_delete(&mapping->page_tree, page->index); page->mapping = NULL; @@ -500,10 +499,13 @@ struct page *__page_cache_alloc(gfp_t gfp) struct page *page; if (cpuset_do_page_mem_spread()) { - get_mems_allowed(); - n = cpuset_mem_spread_node(); - page = alloc_pages_exact_node(n, gfp, 0); - put_mems_allowed(); + unsigned int cpuset_mems_cookie; + do { + cpuset_mems_cookie = get_mems_allowed(); + n = cpuset_mem_spread_node(); + page = alloc_pages_exact_node(n, gfp, 0); + } while (!put_mems_allowed(cpuset_mems_cookie) && !page); + return page; } return alloc_pages(gfp, 0); @@ -1318,10 +1320,10 @@ int file_read_actor(read_descriptor_t *desc, struct page *page, * taking the kmap. */ if (!fault_in_pages_writeable(desc->arg.buf, size)) { - kaddr = kmap_atomic(page, KM_USER0); + kaddr = kmap_atomic(page); left = __copy_to_user_inatomic(desc->arg.buf, kaddr + offset, size); - kunmap_atomic(kaddr, KM_USER0); + kunmap_atomic(kaddr); if (left == 0) goto success; } @@ -1400,15 +1402,12 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, unsigned long seg = 0; size_t count; loff_t *ppos = &iocb->ki_pos; - struct blk_plug plug; count = 0; retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); if (retval) return retval; - blk_start_plug(&plug); - /* coalesce the iovecs and go direct-to-BIO for O_DIRECT */ if (filp->f_flags & O_DIRECT) { loff_t size; @@ -1424,8 +1423,12 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, retval = filemap_write_and_wait_range(mapping, pos, pos + iov_length(iov, nr_segs) - 1); if (!retval) { + struct blk_plug plug; + + blk_start_plug(&plug); retval = mapping->a_ops->direct_IO(READ, iocb, iov, pos, nr_segs); + blk_finish_plug(&plug); } if (retval > 0) { *ppos = pos + retval; @@ -1481,7 +1484,6 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov, break; } out: - blk_finish_plug(&plug); return retval; } EXPORT_SYMBOL(generic_file_aio_read); @@ -2045,7 +2047,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page, size_t copied; BUG_ON(!in_atomic()); - kaddr = kmap_atomic(page, KM_USER0); + kaddr = kmap_atomic(page); if (likely(i->nr_segs == 1)) { int left; char __user *buf = i->iov->iov_base + i->iov_offset; @@ -2055,7 +2057,7 @@ size_t iov_iter_copy_from_user_atomic(struct page *page, copied = __iovec_copy_from_user_inatomic(kaddr + offset, i->iov, i->iov_offset, bytes); } - kunmap_atomic(kaddr, KM_USER0); + kunmap_atomic(kaddr); return copied; } @@ -2341,7 +2343,9 @@ struct page *grab_cache_page_write_begin(struct address_space *mapping, struct page *page; gfp_t gfp_notmask = 0; - gfp_mask = mapping_gfp_mask(mapping) | __GFP_WRITE; + gfp_mask = mapping_gfp_mask(mapping); + if (mapping_cap_account_dirty(mapping)) + gfp_mask |= __GFP_WRITE; if (flags & AOP_FLAG_NOFS) gfp_notmask = __GFP_FS; repeat: diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c index f91b2f687343..a4eb31132229 100644 --- a/mm/filemap_xip.c +++ b/mm/filemap_xip.c @@ -263,7 +263,12 @@ found: xip_pfn); if (err == -ENOMEM) return VM_FAULT_OOM; - BUG_ON(err); + /* + * err == -EBUSY is fine, we've raced against another thread + * that faulted-in the same page + */ + if (err != -EBUSY) + BUG_ON(err); return VM_FAULT_NOPAGE; } else { int err, ret = VM_FAULT_OOM; diff --git a/mm/huge_memory.c b/mm/huge_memory.c index b3ffc21ce801..f0e5306eeb55 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -671,6 +671,7 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm, set_pmd_at(mm, haddr, pmd, entry); prepare_pmd_huge_pte(pgtable, mm); add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR); + mm->nr_ptes++; spin_unlock(&mm->page_table_lock); } @@ -789,6 +790,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, pmd = pmd_mkold(pmd_wrprotect(pmd)); set_pmd_at(dst_mm, addr, dst_pmd, pmd); prepare_pmd_huge_pte(pgtable, dst_mm); + dst_mm->nr_ptes++; ret = 0; out_unlock: @@ -887,7 +889,6 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm, } kfree(pages); - mm->nr_ptes++; smp_wmb(); /* make pte visible before pmd */ pmd_populate(mm, pmd, pgtable); page_remove_rmap(page); @@ -1030,31 +1031,23 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma, { int ret = 0; - spin_lock(&tlb->mm->page_table_lock); - if (likely(pmd_trans_huge(*pmd))) { - if (unlikely(pmd_trans_splitting(*pmd))) { - spin_unlock(&tlb->mm->page_table_lock); - wait_split_huge_page(vma->anon_vma, - pmd); - } else { - struct page *page; - pgtable_t pgtable; - pgtable = get_pmd_huge_pte(tlb->mm); - page = pmd_page(*pmd); - pmd_clear(pmd); - tlb_remove_pmd_tlb_entry(tlb, pmd, addr); - page_remove_rmap(page); - VM_BUG_ON(page_mapcount(page) < 0); - add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); - VM_BUG_ON(!PageHead(page)); - spin_unlock(&tlb->mm->page_table_lock); - tlb_remove_page(tlb, page); - pte_free(tlb->mm, pgtable); - ret = 1; - } - } else + if (__pmd_trans_huge_lock(pmd, vma) == 1) { + struct page *page; + pgtable_t pgtable; + pgtable = get_pmd_huge_pte(tlb->mm); + page = pmd_page(*pmd); + pmd_clear(pmd); + tlb_remove_pmd_tlb_entry(tlb, pmd, addr); + page_remove_rmap(page); + VM_BUG_ON(page_mapcount(page) < 0); + add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR); + VM_BUG_ON(!PageHead(page)); + tlb->mm->nr_ptes--; spin_unlock(&tlb->mm->page_table_lock); - + tlb_remove_page(tlb, page); + pte_free(tlb->mm, pgtable); + ret = 1; + } return ret; } @@ -1064,21 +1057,15 @@ int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, { int ret = 0; - spin_lock(&vma->vm_mm->page_table_lock); - if (likely(pmd_trans_huge(*pmd))) { - ret = !pmd_trans_splitting(*pmd); - spin_unlock(&vma->vm_mm->page_table_lock); - if (unlikely(!ret)) - wait_split_huge_page(vma->anon_vma, pmd); - else { - /* - * All logical pages in the range are present - * if backed by a huge page. - */ - memset(vec, 1, (end - addr) >> PAGE_SHIFT); - } - } else + if (__pmd_trans_huge_lock(pmd, vma) == 1) { + /* + * All logical pages in the range are present + * if backed by a huge page. + */ spin_unlock(&vma->vm_mm->page_table_lock); + memset(vec, 1, (end - addr) >> PAGE_SHIFT); + ret = 1; + } return ret; } @@ -1108,20 +1095,11 @@ int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma, goto out; } - spin_lock(&mm->page_table_lock); - if (likely(pmd_trans_huge(*old_pmd))) { - if (pmd_trans_splitting(*old_pmd)) { - spin_unlock(&mm->page_table_lock); - wait_split_huge_page(vma->anon_vma, old_pmd); - ret = -1; - } else { - pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); - VM_BUG_ON(!pmd_none(*new_pmd)); - set_pmd_at(mm, new_addr, new_pmd, pmd); - spin_unlock(&mm->page_table_lock); - ret = 1; - } - } else { + ret = __pmd_trans_huge_lock(old_pmd, vma); + if (ret == 1) { + pmd = pmdp_get_and_clear(mm, old_addr, old_pmd); + VM_BUG_ON(!pmd_none(*new_pmd)); + set_pmd_at(mm, new_addr, new_pmd, pmd); spin_unlock(&mm->page_table_lock); } out: @@ -1134,24 +1112,41 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, struct mm_struct *mm = vma->vm_mm; int ret = 0; - spin_lock(&mm->page_table_lock); + if (__pmd_trans_huge_lock(pmd, vma) == 1) { + pmd_t entry; + entry = pmdp_get_and_clear(mm, addr, pmd); + entry = pmd_modify(entry, newprot); + set_pmd_at(mm, addr, pmd, entry); + spin_unlock(&vma->vm_mm->page_table_lock); + ret = 1; + } + + return ret; +} + +/* + * Returns 1 if a given pmd maps a stable (not under splitting) thp. + * Returns -1 if it maps a thp under splitting. Returns 0 otherwise. + * + * Note that if it returns 1, this routine returns without unlocking page + * table locks. |