From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f68.google.com ([74.125.82.68]:35063 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753472AbdGNMA4 (ORCPT ); Fri, 14 Jul 2017 08:00:56 -0400 Received: by mail-wm0-f68.google.com with SMTP id u23so10465671wma.2 for ; Fri, 14 Jul 2017 05:00:56 -0700 (PDT) From: Timofey Titovets To: linux-btrfs@vger.kernel.org Cc: Timofey Titovets Subject: [PATCH v2] Btrfs: add skeleton code for compression heuristic Date: Fri, 14 Jul 2017 15:00:46 +0300 Message-Id: <20170714120046.3451-1-nefelim4ag@gmail.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: For now that code just return true Later more complex heuristic code will be added Changes v1 -> v2: - Heuristic call moved into inode_need_compress() function Signed-off-by: Timofey Titovets --- fs/btrfs/compression.c | 22 ++++++++++++++++++++++ fs/btrfs/compression.h | 2 ++ fs/btrfs/inode.c | 18 ++++++++++++------ 3 files changed, 36 insertions(+), 6 deletions(-) diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c index 2c0b7b57fcd5..d0cf2024def7 100644 --- a/fs/btrfs/compression.c +++ b/fs/btrfs/compression.c @@ -1046,3 +1046,25 @@ int btrfs_decompress_buf2page(const char *buf, unsigned long buf_start, return 1; } + +/* + * Heuristic skeleton + * For now just would be a naive and very optimistic 'return true'. + */ +int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end) +{ + u64 index = start >> PAGE_SHIFT; + u64 end_index = end >> PAGE_SHIFT; + struct page *page; + int ret = 1; + + while (index <= end_index) { + page = find_get_page(inode->i_mapping, index); + kmap(page); + kunmap(page); + put_page(page); + index++; + } + + return ret; +} diff --git a/fs/btrfs/compression.h b/fs/btrfs/compression.h index 87f6d3332163..8508ba6b9aef 100644 --- a/fs/btrfs/compression.h +++ b/fs/btrfs/compression.h @@ -129,4 +129,6 @@ struct btrfs_compress_op { extern const struct btrfs_compress_op btrfs_zlib_compress; extern const struct btrfs_compress_op btrfs_lzo_compress; +int btrfs_compress_heuristic(struct inode *inode, u64 start, u64 end); + #endif diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 06dea7c89bbd..27922b29fa4e 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -392,20 +392,26 @@ static noinline int add_async_extent(struct async_cow *cow, return 0; } -static inline int inode_need_compress(struct inode *inode) +static inline int inode_need_compress(struct inode *inode, u64 start, u64 end) { + int ret = 0; struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); /* force compress */ if (btrfs_test_opt(fs_info, FORCE_COMPRESS)) - return 1; + goto try_compress; /* bad compression ratios */ if (BTRFS_I(inode)->flags & BTRFS_INODE_NOCOMPRESS) - return 0; + goto skip_compress; if (btrfs_test_opt(fs_info, COMPRESS) || BTRFS_I(inode)->flags & BTRFS_INODE_COMPRESS || BTRFS_I(inode)->force_compress) - return 1; + goto try_compress; + goto skip_compress; +try_compress: + ret = btrfs_compress_heuristic(inode, start, end); + return ret; +skip_compress: return 0; } @@ -503,7 +509,7 @@ static noinline void compress_file_range(struct inode *inode, * inode has not been flagged as nocompress. This flag can * change at any time if we discover bad compression ratios. */ - if (inode_need_compress(inode)) { + if (inode_need_compress(inode, start, end)) { WARN_ON(pages); pages = kcalloc(nr_pages, sizeof(struct page *), GFP_NOFS); if (!pages) { @@ -1576,7 +1582,7 @@ static int run_delalloc_range(void *private_data, struct page *locked_page, } else if (BTRFS_I(inode)->flags & BTRFS_INODE_PREALLOC && !force_cow) { ret = run_delalloc_nocow(inode, locked_page, start, end, page_started, 0, nr_written); - } else if (!inode_need_compress(inode)) { + } else if (!inode_need_compress(inode, start, end)) { ret = cow_file_range(inode, locked_page, start, end, end, page_started, nr_written, 1, NULL); } else { -- 2.13.2