From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f193.google.com ([209.85.128.193]:34102 "EHLO mail-wr0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752770AbdHWA1J (ORCPT ); Tue, 22 Aug 2017 20:27:09 -0400 Received: by mail-wr0-f193.google.com with SMTP id p14so152865wrg.1 for ; Tue, 22 Aug 2017 17:27:09 -0700 (PDT) From: Timofey Titovets To: linux-btrfs@vger.kernel.org Cc: Timofey Titovets Subject: [PATCH v5 2/6] Btrfs: heuristic workspace add bucket and sample items Date: Wed, 23 Aug 2017 03:26:46 +0300 Message-Id: <20170823002650.3133-3-nefelim4ag@gmail.com> In-Reply-To: <20170823002650.3133-1-nefelim4ag@gmail.com> References: <20170823002650.3133-1-nefelim4ag@gmail.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: Heuristic workspace: - Add bucket for storing byte type counters - Add sample array for storing partial copy of input data range - Add counter for store current sample size to workspace Signed-off-by: Timofey Titovets --- fs/btrfs/heuristic.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/fs/btrfs/heuristic.c b/fs/btrfs/heuristic.c index 96ae3e9334bc..2c2cadc9dfad 100644 --- a/fs/btrfs/heuristic.c +++ b/fs/btrfs/heuristic.c @@ -20,13 +20,36 @@ #include #include "compression.h" +#define READ_SIZE 16 +#define ITER_SHIFT 256 +#define BUCKET_SIZE 256 + +/* + * While mapping 128KiB range into pages (with 4k PAGE_SIZE as ex), + * and iterate that with index <= index_end + * code get 0-32 items, that a 33 pages + */ +#define MAX_INPUT_PAGES ((BTRFS_MAX_UNCOMPRESSED >> PAGE_SHIFT)+1) +#define MAX_SAMPLE_SIZE (MAX_INPUT_PAGES*PAGE_SIZE*READ_SIZE/ITER_SHIFT) + +struct bucket_item { + u32 count; +}; + struct workspace { + u8 *sample; + /* Partial copy of input data */ + u32 sample_size; + /* Bucket store counter for each byte type */ + struct bucket_item bucket[BUCKET_SIZE]; struct list_head list; }; static void heuristic_free_workspace(struct list_head *ws) { struct workspace *workspace = list_entry(ws, struct workspace, list); + + kvfree(workspace->sample); kfree(workspace); } @@ -38,9 +61,16 @@ static struct list_head *heuristic_alloc_workspace(void) if (!workspace) return ERR_PTR(-ENOMEM); + workspace->sample = kvmalloc(MAX_SAMPLE_SIZE, GFP_KERNEL); + if (!workspace->sample) + goto fail; + INIT_LIST_HEAD(&workspace->list); return &workspace->list; +fail: + heuristic_free_workspace(&workspace->list); + return ERR_PTR(-ENOMEM); } static int heuristic(struct list_head *ws, struct inode *inode, -- 2.14.1