[PATCH 2/2] erofs-utils: lib: adjust MicroLZMA default dictionary size

[Gao Xiang]

If dict_size is not given, it will be set as max(32k, pclustersize * 8)
but no more than Z_EROFS_LZMA_MAX_DICT_SIZE.

Also kill an obsolete warning since multi-threaded support is landed.

Signed-off-by: Gao Xiang <hsiangkao at linux.alibaba.com>
---
 lib/compressor_liblzma.c | 19 +++++++++++--------
 mkfs/main.c              |  8 ++++++--
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/lib/compressor_liblzma.c b/lib/compressor_liblzma.c
index 2f19a93..d609a28 100644
--- a/lib/compressor_liblzma.c
+++ b/lib/compressor_liblzma.c
@@ -70,11 +70,18 @@ static int erofs_compressor_liblzma_setlevel(struct erofs_compress *c,
 static int erofs_compressor_liblzma_setdictsize(struct erofs_compress *c,
 						u32 dict_size)
 {
-	if (!dict_size)
-		dict_size = erofs_compressor_lzma.default_dictsize;
+	if (!dict_size) {
+		if (erofs_compressor_lzma.default_dictsize) {
+			dict_size = erofs_compressor_lzma.default_dictsize;
+		} else {
+			dict_size = min_t(u32, Z_EROFS_LZMA_MAX_DICT_SIZE,
+					  cfg.c_mkfs_pclustersize_max << 3);
+			if (dict_size < 32768)
+				dict_size = 32768;
+		}
+	}
 
-	if (dict_size > erofs_compressor_lzma.max_dictsize ||
-	    dict_size < 4096) {
+	if (dict_size > Z_EROFS_LZMA_MAX_DICT_SIZE || dict_size < 4096) {
 		erofs_err("invalid dictionary size %u", dict_size);
 		return -EINVAL;
 	}
@@ -86,7 +93,6 @@ static int erofs_compressor_liblzma_init(struct erofs_compress *c)
 {
 	struct erofs_liblzma_context *ctx;
 	u32 preset;
-	static erofs_atomic_bool_t __warnonce;
 
 	ctx = malloc(sizeof(*ctx));
 	if (!ctx)
@@ -105,15 +111,12 @@ static int erofs_compressor_liblzma_init(struct erofs_compress *c)
 	ctx->opt.dict_size = c->dict_size;
 
 	c->private_data = ctx;
-	if (!erofs_atomic_test_and_set(&__warnonce))
-		erofs_warn("It may take a longer time since MicroLZMA is still single-threaded for now.");
 	return 0;
 }
 
 const struct erofs_compressor erofs_compressor_lzma = {
 	.default_level = LZMA_PRESET_DEFAULT,
 	.best_level = 109,
-	.default_dictsize = Z_EROFS_LZMA_MAX_DICT_SIZE,
 	.max_dictsize = Z_EROFS_LZMA_MAX_DICT_SIZE,
 	.init = erofs_compressor_liblzma_init,
 	.exit = erofs_compressor_liblzma_exit,
diff --git a/mkfs/main.c b/mkfs/main.c
index 3d19f60..bbf4f43 100644
--- a/mkfs/main.c
+++ b/mkfs/main.c
@@ -137,8 +137,12 @@ static void usage(int argc, char **argv)
 				       spaces, s->c->best_level, s->c->default_level);
 		}
 		if (s->c->setdictsize) {
-			printf("%s  [,dictsize=<dictsize>]\t(default=%u, max=%u)\n",
-			       spaces, s->c->default_dictsize, s->c->max_dictsize);
+			if (s->c->default_dictsize)
+				printf("%s  [,dictsize=<dictsize>]\t(default=%u, max=%u)\n",
+				       spaces, s->c->default_dictsize, s->c->max_dictsize);
+			else
+				printf("%s  [,dictsize=<dictsize>]\t(default=<auto>, max=%u)\n",
+				       spaces, s->c->max_dictsize);
 		}
 	}
 	printf(
-- 
2.39.3