From: Mikhail Zaslonko <zaslonko@xxxxxxxxxxxxx> Subject: btrfs: use larger zlib buffer for s390 hardware compression In order to benefit from s390 zlib hardware compression support, increase the btrfs zlib workspace buffer size from 1 to 4 pages (if s390 zlib hardware support is enabled on the machine). This brings up to 60% better performance in hardware on s390 compared to the PAGE_SIZE buffer and much more compared to the software zlib processing in btrfs. In case of memory pressure, fall back to a single page buffer during workspace allocation. The data compressed with larger input buffers will still conform to zlib standard and thus can be decompressed also on a systems that uses only PAGE_SIZE buffer for btrfs zlib. Link: http://lkml.kernel.org/r/20200108105103.29028-1-zaslonko@xxxxxxxxxxxxx Signed-off-by: Mikhail Zaslonko <zaslonko@xxxxxxxxxxxxx> Reviewed-by: David Sterba <dsterba@xxxxxxxx> Cc: Chris Mason <clm@xxxxxx> Cc: Josef Bacik <josef@xxxxxxxxxxxxxx> Cc: David Sterba <dsterba@xxxxxxxx> Cc: Richard Purdie <rpurdie@xxxxxxxxx> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx> Cc: Eduard Shishkin <edward6@xxxxxxxxxxxxx> Cc: Ilya Leoshkevich <iii@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/btrfs/compression.c | 2 fs/btrfs/zlib.c | 135 ++++++++++++++++++++++++++++----------- 2 files changed, 101 insertions(+), 36 deletions(-) --- a/fs/btrfs/compression.c~btrfs-use-larger-zlib-buffer-for-s390-hardware-compression +++ a/fs/btrfs/compression.c @@ -1290,7 +1290,7 @@ int btrfs_decompress_buf2page(const char /* copy bytes from the working buffer into the pages */ while (working_bytes > 0) { bytes = min_t(unsigned long, bvec.bv_len, - PAGE_SIZE - buf_offset); + PAGE_SIZE - (buf_offset % PAGE_SIZE)); bytes = min(bytes, working_bytes); kaddr = kmap_atomic(bvec.bv_page); --- a/fs/btrfs/zlib.c~btrfs-use-larger-zlib-buffer-for-s390-hardware-compression +++ a/fs/btrfs/zlib.c @@ -20,9 +20,13 @@ #include <linux/refcount.h> #include "compression.h" +/* workspace buffer size for s390 zlib hardware support */ +#define ZLIB_DFLTCC_BUF_SIZE (4 * PAGE_SIZE) + struct workspace { z_stream strm; char *buf; + unsigned int buf_size; struct list_head list; int level; }; @@ -61,7 +65,21 @@ struct list_head *zlib_alloc_workspace(u zlib_inflate_workspacesize()); workspace->strm.workspace = kvmalloc(workspacesize, GFP_KERNEL); workspace->level = level; - workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + workspace->buf = NULL; + /* + * In case of s390 zlib hardware support, allocate lager workspace + * buffer. If allocator fails, fall back to a single page buffer. + */ + if (zlib_deflate_dfltcc_enabled()) { + workspace->buf = kmalloc(ZLIB_DFLTCC_BUF_SIZE, + __GFP_NOMEMALLOC | __GFP_NORETRY | + __GFP_NOWARN | GFP_NOIO); + workspace->buf_size = ZLIB_DFLTCC_BUF_SIZE; + } + if (!workspace->buf) { + workspace->buf = kmalloc(PAGE_SIZE, GFP_KERNEL); + workspace->buf_size = PAGE_SIZE; + } if (!workspace->strm.workspace || !workspace->buf) goto fail; @@ -85,6 +103,7 @@ int zlib_compress_pages(struct list_head struct page *in_page = NULL; struct page *out_page = NULL; unsigned long bytes_left; + unsigned int in_buf_pages; unsigned long len = *total_out; unsigned long nr_dest_pages = *out_pages; const unsigned long max_out = nr_dest_pages * PAGE_SIZE; @@ -102,9 +121,6 @@ int zlib_compress_pages(struct list_head workspace->strm.total_in = 0; workspace->strm.total_out = 0; - in_page = find_get_page(mapping, start >> PAGE_SHIFT); - data_in = kmap(in_page); - out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); if (out_page == NULL) { ret = -ENOMEM; @@ -114,12 +130,51 @@ int zlib_compress_pages(struct list_head pages[0] = out_page; nr_pages = 1; - workspace->strm.next_in = data_in; + workspace->strm.next_in = workspace->buf; + workspace->strm.avail_in = 0; workspace->strm.next_out = cpage_out; workspace->strm.avail_out = PAGE_SIZE; - workspace->strm.avail_in = min(len, PAGE_SIZE); while (workspace->strm.total_in < len) { + /* + * Get next input pages and copy the contents to + * the workspace buffer if required. + */ + if (workspace->strm.avail_in == 0) { + bytes_left = len - workspace->strm.total_in; + in_buf_pages = min(DIV_ROUND_UP(bytes_left, PAGE_SIZE), + workspace->buf_size / PAGE_SIZE); + if (in_buf_pages > 1) { + int i; + + for (i = 0; i < in_buf_pages; i++) { + if (in_page) { + kunmap(in_page); + put_page(in_page); + } + in_page = find_get_page(mapping, + start >> PAGE_SHIFT); + data_in = kmap(in_page); + memcpy(workspace->buf + i * PAGE_SIZE, + data_in, PAGE_SIZE); + start += PAGE_SIZE; + } + workspace->strm.next_in = workspace->buf; + } else { + if (in_page) { + kunmap(in_page); + put_page(in_page); + } + in_page = find_get_page(mapping, + start >> PAGE_SHIFT); + data_in = kmap(in_page); + start += PAGE_SIZE; + workspace->strm.next_in = data_in; + } + workspace->strm.avail_in = min(bytes_left, + (unsigned long) workspace->buf_size); + } + ret = zlib_deflate(&workspace->strm, Z_SYNC_FLUSH); if (ret != Z_OK) { pr_debug("BTRFS: deflate in loop returned %d\n", @@ -161,33 +216,43 @@ int zlib_compress_pages(struct list_head /* we're all done */ if (workspace->strm.total_in >= len) break; - - /* we've read in a full page, get a new one */ - if (workspace->strm.avail_in == 0) { - if (workspace->strm.total_out > max_out) - break; - - bytes_left = len - workspace->strm.total_in; - kunmap(in_page); - put_page(in_page); - - start += PAGE_SIZE; - in_page = find_get_page(mapping, - start >> PAGE_SHIFT); - data_in = kmap(in_page); - workspace->strm.avail_in = min(bytes_left, - PAGE_SIZE); - workspace->strm.next_in = data_in; - } + if (workspace->strm.total_out > max_out) + break; } workspace->strm.avail_in = 0; - ret = zlib_deflate(&workspace->strm, Z_FINISH); - zlib_deflateEnd(&workspace->strm); - - if (ret != Z_STREAM_END) { - ret = -EIO; - goto out; + /* + * Call deflate with Z_FINISH flush parameter providing more output + * space but no more input data, until it returns with Z_STREAM_END. + */ + while (ret != Z_STREAM_END) { + ret = zlib_deflate(&workspace->strm, Z_FINISH); + if (ret == Z_STREAM_END) + break; + if (ret != Z_OK && ret != Z_BUF_ERROR) { + zlib_deflateEnd(&workspace->strm); + ret = -EIO; + goto out; + } else if (workspace->strm.avail_out == 0) { + /* get another page for the stream end */ + kunmap(out_page); + if (nr_pages == nr_dest_pages) { + out_page = NULL; + ret = -E2BIG; + goto out; + } + out_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM); + if (out_page == NULL) { + ret = -ENOMEM; + goto out; + } + cpage_out = kmap(out_page); + pages[nr_pages] = out_page; + nr_pages++; + workspace->strm.avail_out = PAGE_SIZE; + workspace->strm.next_out = cpage_out; + } } + zlib_deflateEnd(&workspace->strm); if (workspace->strm.total_out >= workspace->strm.total_in) { ret = -E2BIG; @@ -231,7 +296,7 @@ int zlib_decompress_bio(struct list_head workspace->strm.total_out = 0; workspace->strm.next_out = workspace->buf; - workspace->strm.avail_out = PAGE_SIZE; + workspace->strm.avail_out = workspace->buf_size; /* If it's deflate, and it's got no preset dictionary, then we can tell zlib to skip the adler32 check. */ @@ -270,7 +335,7 @@ int zlib_decompress_bio(struct list_head } workspace->strm.next_out = workspace->buf; - workspace->strm.avail_out = PAGE_SIZE; + workspace->strm.avail_out = workspace->buf_size; if (workspace->strm.avail_in == 0) { unsigned long tmp; @@ -320,7 +385,7 @@ int zlib_decompress(struct list_head *ws workspace->strm.total_in = 0; workspace->strm.next_out = workspace->buf; - workspace->strm.avail_out = PAGE_SIZE; + workspace->strm.avail_out = workspace->buf_size; workspace->strm.total_out = 0; /* If it's deflate, and it's got no preset dictionary, then we can tell zlib to skip the adler32 check. */ @@ -364,7 +429,7 @@ int zlib_decompress(struct list_head *ws buf_offset = 0; bytes = min(PAGE_SIZE - pg_offset, - PAGE_SIZE - buf_offset); + PAGE_SIZE - (buf_offset % PAGE_SIZE)); bytes = min(bytes, bytes_left); kaddr = kmap_atomic(dest_page); @@ -375,7 +440,7 @@ int zlib_decompress(struct list_head *ws bytes_left -= bytes; next: workspace->strm.next_out = workspace->buf; - workspace->strm.avail_out = PAGE_SIZE; + workspace->strm.avail_out = workspace->buf_size; } if (ret != Z_STREAM_END && bytes_left != 0) _
