From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 676B21A1E54 for ; Tue, 21 Jun 2016 08:45:54 -0700 (PDT) From: Jan Kara Subject: [PATCH 3/3] dax: Clear dirty entry tags on cache flush Date: Tue, 21 Jun 2016 17:45:15 +0200 Message-Id: <1466523915-14644-4-git-send-email-jack@suse.cz> In-Reply-To: <1466523915-14644-1-git-send-email-jack@suse.cz> References: <1466523915-14644-1-git-send-email-jack@suse.cz> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-nvdimm@lists.01.org Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Jan Kara List-ID: Currently we never clear dirty tags in DAX mappings and thus address ranges to flush accumulate. Now that we have locking of radix tree entries, we have all the locking necessary to reliably clear the radix tree dirty tag when flushing caches for corresponding address range. Similarly to page_mkclean() we also have to write-protect pages to get a page fault when the page is next written to so that we can mark the entry dirty again. Signed-off-by: Jan Kara --- fs/dax.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 68 insertions(+), 1 deletion(-) diff --git a/fs/dax.c b/fs/dax.c index 5209f8cd0bee..c0c4eecb5f73 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -31,6 +31,7 @@ #include #include #include +#include /* * We use lowest available bit in exceptional entry for locking, other two @@ -665,6 +666,59 @@ static void *dax_insert_mapping_entry(struct address_space *mapping, return new_entry; } +static inline unsigned long +pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) +{ + unsigned long address; + + address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); + VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); + return address; +} + +/* Walk all mappings of a given index of a file and writeprotect them */ +static void dax_mapping_entry_mkclean(struct address_space *mapping, + pgoff_t index, unsigned long pfn) +{ + struct vm_area_struct *vma; + pte_t *ptep; + pte_t pte; + spinlock_t *ptl; + bool changed; + + i_mmap_lock_read(mapping); + vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { + unsigned long address; + + cond_resched(); + + if (!(vma->vm_flags & VM_SHARED)) + continue; + + address = pgoff_address(index, vma); + changed = false; + if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) + continue; + if (pfn != pte_pfn(*ptep)) + goto unlock; + if (!pte_dirty(*ptep) && !pte_write(*ptep)) + goto unlock; + + flush_cache_page(vma, address, pfn); + pte = ptep_clear_flush(vma, address, ptep); + pte = pte_wrprotect(pte); + pte = pte_mkclean(pte); + set_pte_at(vma->vm_mm, address, ptep, pte); + changed = true; +unlock: + pte_unmap_unlock(pte, ptl); + + if (changed) + mmu_notifier_invalidate_page(vma->vm_mm, address); + } + i_mmap_unlock_read(mapping); +} + static int dax_writeback_one(struct block_device *bdev, struct address_space *mapping, pgoff_t index, void *entry) { @@ -723,17 +777,30 @@ static int dax_writeback_one(struct block_device *bdev, * eventually calls cond_resched(). */ ret = dax_map_atomic(bdev, &dax); - if (ret < 0) + if (ret < 0) { + put_locked_mapping_entry(mapping, index, entry); return ret; + } if (WARN_ON_ONCE(ret < dax.size)) { ret = -EIO; goto unmap; } + dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(dax.pfn)); wb_cache_pmem(dax.addr, dax.size); + /* + * After we have flushed the cache, we can clear the dirty tag. There + * cannot be new dirty data in the pfn after the flush has completed as + * the pfn mappings are writeprotected and fault waits for mapping + * entry lock. + */ + spin_lock_irq(&mapping->tree_lock); + radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY); + spin_unlock_irq(&mapping->tree_lock); unmap: dax_unmap_atomic(bdev, &dax); + put_locked_mapping_entry(mapping, index, entry); return ret; put_unlock: -- 2.6.6 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Jan Kara To: linux-nvdimm@lists.01.org Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Dan Williams , Ross Zwisler , Jan Kara Subject: [PATCH 3/3] dax: Clear dirty entry tags on cache flush Date: Tue, 21 Jun 2016 17:45:15 +0200 Message-Id: <1466523915-14644-4-git-send-email-jack@suse.cz> In-Reply-To: <1466523915-14644-1-git-send-email-jack@suse.cz> References: <1466523915-14644-1-git-send-email-jack@suse.cz> Sender: owner-linux-mm@kvack.org List-ID: Currently we never clear dirty tags in DAX mappings and thus address ranges to flush accumulate. Now that we have locking of radix tree entries, we have all the locking necessary to reliably clear the radix tree dirty tag when flushing caches for corresponding address range. Similarly to page_mkclean() we also have to write-protect pages to get a page fault when the page is next written to so that we can mark the entry dirty again. Signed-off-by: Jan Kara --- fs/dax.c | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 68 insertions(+), 1 deletion(-) diff --git a/fs/dax.c b/fs/dax.c index 5209f8cd0bee..c0c4eecb5f73 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -31,6 +31,7 @@ #include #include #include +#include /* * We use lowest available bit in exceptional entry for locking, other two @@ -665,6 +666,59 @@ static void *dax_insert_mapping_entry(struct address_space *mapping, return new_entry; } +static inline unsigned long +pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) +{ + unsigned long address; + + address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); + VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); + return address; +} + +/* Walk all mappings of a given index of a file and writeprotect them */ +static void dax_mapping_entry_mkclean(struct address_space *mapping, + pgoff_t index, unsigned long pfn) +{ + struct vm_area_struct *vma; + pte_t *ptep; + pte_t pte; + spinlock_t *ptl; + bool changed; + + i_mmap_lock_read(mapping); + vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { + unsigned long address; + + cond_resched(); + + if (!(vma->vm_flags & VM_SHARED)) + continue; + + address = pgoff_address(index, vma); + changed = false; + if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) + continue; + if (pfn != pte_pfn(*ptep)) + goto unlock; + if (!pte_dirty(*ptep) && !pte_write(*ptep)) + goto unlock; + + flush_cache_page(vma, address, pfn); + pte = ptep_clear_flush(vma, address, ptep); + pte = pte_wrprotect(pte); + pte = pte_mkclean(pte); + set_pte_at(vma->vm_mm, address, ptep, pte); + changed = true; +unlock: + pte_unmap_unlock(pte, ptl); + + if (changed) + mmu_notifier_invalidate_page(vma->vm_mm, address); + } + i_mmap_unlock_read(mapping); +} + static int dax_writeback_one(struct block_device *bdev, struct address_space *mapping, pgoff_t index, void *entry) { @@ -723,17 +777,30 @@ static int dax_writeback_one(struct block_device *bdev, * eventually calls cond_resched(). */ ret = dax_map_atomic(bdev, &dax); - if (ret < 0) + if (ret < 0) { + put_locked_mapping_entry(mapping, index, entry); return ret; + } if (WARN_ON_ONCE(ret < dax.size)) { ret = -EIO; goto unmap; } + dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(dax.pfn)); wb_cache_pmem(dax.addr, dax.size); + /* + * After we have flushed the cache, we can clear the dirty tag. There + * cannot be new dirty data in the pfn after the flush has completed as + * the pfn mappings are writeprotected and fault waits for mapping + * entry lock. + */ + spin_lock_irq(&mapping->tree_lock); + radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY); + spin_unlock_irq(&mapping->tree_lock); unmap: dax_unmap_atomic(bdev, &dax); + put_locked_mapping_entry(mapping, index, entry); return ret; put_unlock: -- 2.6.6 -- 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: email@kvack.org