forked from Minki/linux
btrfs: move some zstd work data from stack to workspace
* ZSTD_inBuffer in_buf * ZSTD_outBuffer out_buf are used in all functions to pass the compression parameters and the local variables consume some space. We can move them to the workspace and reduce the stack consumption: zstd.c:zstd_decompress -24 (136 -> 112) zstd.c:zstd_decompress_bio -24 (144 -> 120) zstd.c:zstd_compress_pages -24 (264 -> 240) Signed-off-by: David Sterba <dsterba@suse.com> Reviewed-by: Nick Terrell <terrelln@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba
parent
5302e08964
commit
431e98226c
132
fs/btrfs/zstd.c
132
fs/btrfs/zstd.c
@ -43,6 +43,8 @@ struct workspace {
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size_t size;
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char *buf;
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struct list_head list;
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ZSTD_inBuffer in_buf;
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ZSTD_outBuffer out_buf;
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};
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static void zstd_free_workspace(struct list_head *ws)
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@ -94,8 +96,6 @@ static int zstd_compress_pages(struct list_head *ws,
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int nr_pages = 0;
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struct page *in_page = NULL; /* The current page to read */
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struct page *out_page = NULL; /* The current page to write to */
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ZSTD_inBuffer in_buf = { NULL, 0, 0 };
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ZSTD_outBuffer out_buf = { NULL, 0, 0 };
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unsigned long tot_in = 0;
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unsigned long tot_out = 0;
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unsigned long len = *total_out;
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@ -118,9 +118,9 @@ static int zstd_compress_pages(struct list_head *ws,
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/* map in the first page of input data */
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in_page = find_get_page(mapping, start >> PAGE_SHIFT);
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in_buf.src = kmap(in_page);
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in_buf.pos = 0;
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in_buf.size = min_t(size_t, len, PAGE_SIZE);
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workspace->in_buf.src = kmap(in_page);
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workspace->in_buf.pos = 0;
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workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
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/* Allocate and map in the output buffer */
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@ -130,14 +130,15 @@ static int zstd_compress_pages(struct list_head *ws,
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goto out;
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}
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pages[nr_pages++] = out_page;
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out_buf.dst = kmap(out_page);
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out_buf.pos = 0;
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out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
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workspace->out_buf.dst = kmap(out_page);
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workspace->out_buf.pos = 0;
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workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
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while (1) {
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size_t ret2;
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ret2 = ZSTD_compressStream(stream, &out_buf, &in_buf);
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ret2 = ZSTD_compressStream(stream, &workspace->out_buf,
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&workspace->in_buf);
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if (ZSTD_isError(ret2)) {
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pr_debug("BTRFS: ZSTD_compressStream returned %d\n",
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ZSTD_getErrorCode(ret2));
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@ -146,22 +147,22 @@ static int zstd_compress_pages(struct list_head *ws,
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}
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/* Check to see if we are making it bigger */
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if (tot_in + in_buf.pos > 8192 &&
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tot_in + in_buf.pos <
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tot_out + out_buf.pos) {
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if (tot_in + workspace->in_buf.pos > 8192 &&
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tot_in + workspace->in_buf.pos <
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tot_out + workspace->out_buf.pos) {
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ret = -E2BIG;
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goto out;
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}
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/* We've reached the end of our output range */
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if (out_buf.pos >= max_out) {
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tot_out += out_buf.pos;
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if (workspace->out_buf.pos >= max_out) {
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tot_out += workspace->out_buf.pos;
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ret = -E2BIG;
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goto out;
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}
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/* Check if we need more output space */
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if (out_buf.pos == out_buf.size) {
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if (workspace->out_buf.pos == workspace->out_buf.size) {
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tot_out += PAGE_SIZE;
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max_out -= PAGE_SIZE;
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kunmap(out_page);
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@ -176,19 +177,20 @@ static int zstd_compress_pages(struct list_head *ws,
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goto out;
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}
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pages[nr_pages++] = out_page;
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out_buf.dst = kmap(out_page);
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out_buf.pos = 0;
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out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
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workspace->out_buf.dst = kmap(out_page);
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workspace->out_buf.pos = 0;
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workspace->out_buf.size = min_t(size_t, max_out,
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PAGE_SIZE);
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}
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/* We've reached the end of the input */
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if (in_buf.pos >= len) {
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tot_in += in_buf.pos;
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if (workspace->in_buf.pos >= len) {
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tot_in += workspace->in_buf.pos;
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break;
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}
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/* Check if we need more input */
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if (in_buf.pos == in_buf.size) {
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if (workspace->in_buf.pos == workspace->in_buf.size) {
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tot_in += PAGE_SIZE;
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kunmap(in_page);
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put_page(in_page);
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@ -196,15 +198,15 @@ static int zstd_compress_pages(struct list_head *ws,
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start += PAGE_SIZE;
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len -= PAGE_SIZE;
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in_page = find_get_page(mapping, start >> PAGE_SHIFT);
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in_buf.src = kmap(in_page);
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in_buf.pos = 0;
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in_buf.size = min_t(size_t, len, PAGE_SIZE);
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workspace->in_buf.src = kmap(in_page);
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workspace->in_buf.pos = 0;
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workspace->in_buf.size = min_t(size_t, len, PAGE_SIZE);
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}
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}
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while (1) {
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size_t ret2;
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ret2 = ZSTD_endStream(stream, &out_buf);
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ret2 = ZSTD_endStream(stream, &workspace->out_buf);
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if (ZSTD_isError(ret2)) {
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pr_debug("BTRFS: ZSTD_endStream returned %d\n",
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ZSTD_getErrorCode(ret2));
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@ -212,11 +214,11 @@ static int zstd_compress_pages(struct list_head *ws,
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goto out;
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}
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if (ret2 == 0) {
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tot_out += out_buf.pos;
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tot_out += workspace->out_buf.pos;
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break;
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}
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if (out_buf.pos >= max_out) {
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tot_out += out_buf.pos;
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if (workspace->out_buf.pos >= max_out) {
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tot_out += workspace->out_buf.pos;
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ret = -E2BIG;
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goto out;
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}
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@ -235,9 +237,9 @@ static int zstd_compress_pages(struct list_head *ws,
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goto out;
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}
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pages[nr_pages++] = out_page;
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out_buf.dst = kmap(out_page);
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out_buf.pos = 0;
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out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
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workspace->out_buf.dst = kmap(out_page);
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workspace->out_buf.pos = 0;
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workspace->out_buf.size = min_t(size_t, max_out, PAGE_SIZE);
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}
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if (tot_out >= tot_in) {
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@ -273,8 +275,6 @@ static int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
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unsigned long total_pages_in = DIV_ROUND_UP(srclen, PAGE_SIZE);
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unsigned long buf_start;
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unsigned long total_out = 0;
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ZSTD_inBuffer in_buf = { NULL, 0, 0 };
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ZSTD_outBuffer out_buf = { NULL, 0, 0 };
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stream = ZSTD_initDStream(
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ZSTD_BTRFS_MAX_INPUT, workspace->mem, workspace->size);
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@ -284,18 +284,19 @@ static int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
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goto done;
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}
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in_buf.src = kmap(pages_in[page_in_index]);
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in_buf.pos = 0;
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in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
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workspace->in_buf.src = kmap(pages_in[page_in_index]);
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workspace->in_buf.pos = 0;
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workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
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out_buf.dst = workspace->buf;
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out_buf.pos = 0;
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out_buf.size = PAGE_SIZE;
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workspace->out_buf.dst = workspace->buf;
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workspace->out_buf.pos = 0;
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workspace->out_buf.size = PAGE_SIZE;
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while (1) {
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size_t ret2;
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ret2 = ZSTD_decompressStream(stream, &out_buf, &in_buf);
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ret2 = ZSTD_decompressStream(stream, &workspace->out_buf,
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&workspace->in_buf);
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if (ZSTD_isError(ret2)) {
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pr_debug("BTRFS: ZSTD_decompressStream returned %d\n",
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ZSTD_getErrorCode(ret2));
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@ -303,38 +304,38 @@ static int zstd_decompress_bio(struct list_head *ws, struct compressed_bio *cb)
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goto done;
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}
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buf_start = total_out;
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total_out += out_buf.pos;
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out_buf.pos = 0;
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total_out += workspace->out_buf.pos;
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workspace->out_buf.pos = 0;
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ret = btrfs_decompress_buf2page(out_buf.dst, buf_start,
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total_out, disk_start, orig_bio);
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ret = btrfs_decompress_buf2page(workspace->out_buf.dst,
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buf_start, total_out, disk_start, orig_bio);
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if (ret == 0)
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break;
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if (in_buf.pos >= srclen)
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if (workspace->in_buf.pos >= srclen)
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break;
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/* Check if we've hit the end of a frame */
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if (ret2 == 0)
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break;
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if (in_buf.pos == in_buf.size) {
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if (workspace->in_buf.pos == workspace->in_buf.size) {
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kunmap(pages_in[page_in_index++]);
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if (page_in_index >= total_pages_in) {
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in_buf.src = NULL;
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workspace->in_buf.src = NULL;
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ret = -EIO;
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goto done;
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}
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srclen -= PAGE_SIZE;
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in_buf.src = kmap(pages_in[page_in_index]);
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in_buf.pos = 0;
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in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
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workspace->in_buf.src = kmap(pages_in[page_in_index]);
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workspace->in_buf.pos = 0;
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workspace->in_buf.size = min_t(size_t, srclen, PAGE_SIZE);
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}
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}
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ret = 0;
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zero_fill_bio(orig_bio);
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done:
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if (in_buf.src)
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if (workspace->in_buf.src)
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kunmap(pages_in[page_in_index]);
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return ret;
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}
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@ -348,8 +349,6 @@ static int zstd_decompress(struct list_head *ws, unsigned char *data_in,
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ZSTD_DStream *stream;
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int ret = 0;
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size_t ret2;
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ZSTD_inBuffer in_buf = { NULL, 0, 0 };
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ZSTD_outBuffer out_buf = { NULL, 0, 0 };
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unsigned long total_out = 0;
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unsigned long pg_offset = 0;
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char *kaddr;
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@ -364,16 +363,17 @@ static int zstd_decompress(struct list_head *ws, unsigned char *data_in,
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destlen = min_t(size_t, destlen, PAGE_SIZE);
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in_buf.src = data_in;
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in_buf.pos = 0;
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in_buf.size = srclen;
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workspace->in_buf.src = data_in;
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workspace->in_buf.pos = 0;
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workspace->in_buf.size = srclen;
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out_buf.dst = workspace->buf;
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out_buf.pos = 0;
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out_buf.size = PAGE_SIZE;
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workspace->out_buf.dst = workspace->buf;
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workspace->out_buf.pos = 0;
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workspace->out_buf.size = PAGE_SIZE;
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ret2 = 1;
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while (pg_offset < destlen && in_buf.pos < in_buf.size) {
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while (pg_offset < destlen
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&& workspace->in_buf.pos < workspace->in_buf.size) {
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unsigned long buf_start;
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unsigned long buf_offset;
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unsigned long bytes;
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@ -384,7 +384,8 @@ static int zstd_decompress(struct list_head *ws, unsigned char *data_in,
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ret = -EIO;
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goto finish;
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}
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ret2 = ZSTD_decompressStream(stream, &out_buf, &in_buf);
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ret2 = ZSTD_decompressStream(stream, &workspace->out_buf,
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&workspace->in_buf);
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if (ZSTD_isError(ret2)) {
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pr_debug("BTRFS: ZSTD_decompressStream returned %d\n",
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ZSTD_getErrorCode(ret2));
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@ -393,8 +394,8 @@ static int zstd_decompress(struct list_head *ws, unsigned char *data_in,
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}
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buf_start = total_out;
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total_out += out_buf.pos;
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out_buf.pos = 0;
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total_out += workspace->out_buf.pos;
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workspace->out_buf.pos = 0;
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if (total_out <= start_byte)
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continue;
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@ -405,10 +406,11 @@ static int zstd_decompress(struct list_head *ws, unsigned char *data_in,
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buf_offset = 0;
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bytes = min_t(unsigned long, destlen - pg_offset,
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out_buf.size - buf_offset);
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workspace->out_buf.size - buf_offset);
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kaddr = kmap_atomic(dest_page);
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memcpy(kaddr + pg_offset, out_buf.dst + buf_offset, bytes);
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memcpy(kaddr + pg_offset, workspace->out_buf.dst + buf_offset,
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bytes);
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kunmap_atomic(kaddr);
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pg_offset += bytes;
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