Set sane defaults for backlog and job count

Instead of defaulting to -j 1 and -Q 10 times the job count if no option is
provided, let tar2sqfs and gensquashfs use all available CPUs and about
roughly half the available RAM, if this information can be gathered.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

1 files changed, 44 insertions, 1 deletions

diff --git a/lib/sqfshelper/writer.c b/lib/sqfshelper/writer.c
index e57ad76..7626b1c 100644
--- a/lib/sqfshelper/writer.c
+++ b/lib/sqfshelper/writer.c
@@ -13,14 +13,57 @@
 
 #include <string.h>
 
+#ifdef HAVE_SYS_SYSINFO_H
+#include <sys/sysinfo.h>
+
+static size_t os_get_num_jobs(void)
+{
+	int nprocs;
+
+	nprocs = get_nprocs_conf();
+	return nprocs < 1 ? 1 : nprocs;
+}
+
+static size_t os_get_max_ram(void)
+{
+	struct sysinfo info;
+
+	if (sysinfo(&info)) {
+		perror("sysinfo");
+		return 0;
+	}
+
+	return info.totalram;
+}
+#else
+static size_t os_get_num_jobs(void)
+{
+	return 1;
+}
+
+static size_t os_get_max_ram(void)
+{
+	(void)cfg;
+	return 0;
+}
+#endif
+
 void sqfs_writer_cfg_init(sqfs_writer_cfg_t *cfg)
 {
+	size_t max_ram;
+
 	memset(cfg, 0, sizeof(*cfg));
 
-	cfg->num_jobs = 1;
+	cfg->num_jobs = os_get_num_jobs();
 	cfg->block_size = SQFS_DEFAULT_BLOCK_SIZE;
 	cfg->devblksize = SQFS_DEVBLK_SIZE;
 	cfg->comp_id = compressor_get_default();
+
+	max_ram = os_get_max_ram();
+	cfg->max_backlog = (max_ram / 2) / cfg->block_size;
+
+	if (cfg->max_backlog < 1)
+		cfg->max_backlog = 10 * cfg->num_jobs;
 }
 
 int sqfs_writer_init(sqfs_writer_t *sqfs, const sqfs_writer_cfg_t *wrcfg)