1 files changed, 31 insertions, 12 deletions

diff --git a/src/xz/hardware.c b/src/xz/hardware.c
index d91b4cee..74742fce 100644
--- a/src/xz/hardware.c
+++ b/src/xz/hardware.c
@@ -21,6 +21,9 @@ static uint32_t threadlimit;
 /// Memory usage limit
 static uint64_t memlimit;
 
+/// Total amount of physical RAM
+static uint64_t total_ram;
+
 
 extern void
 hardware_threadlimit_set(uint32_t new_threadlimit)
@@ -48,11 +51,27 @@ hardware_threadlimit_get(void)
 extern void
 hardware_memlimit_set(uint64_t new_memlimit)
 {
-	if (new_memlimit == 0) {
-		// The default is 40 % of total installed physical RAM.
-		hardware_memlimit_set_percentage(40);
-	} else {
+	if (new_memlimit != 0) {
 		memlimit = new_memlimit;
+	} else {
+		// The default depends on the amount of RAM but so that
+		// on "low-memory" systems the relative limit is higher
+		// to make it more likely that files created with "xz -9"
+		// will still decompress without overriding the limit
+		// manually.
+		//
+		// If 40 % of RAM is 80 MiB or more, use 40 % of RAM as
+		// the limit.
+		memlimit = 40 * total_ram / 100;
+		if (memlimit < UINT64_C(80) * 1024 * 1024) {
+			// If 80 % of RAM is less than 80 MiB,
+			// use 80 % of RAM as the limit.
+			memlimit = 80 * total_ram / 100;
+			if (memlimit > UINT64_C(80) * 1024 * 1024) {
+				// Otherwise use 80 MiB as the limit.
+				memlimit = UINT64_C(80) * 1024 * 1024;
+			}
+		}
 	}
 
 	return;
@@ -65,14 +84,7 @@ hardware_memlimit_set_percentage(uint32_t percentage)
 	assert(percentage > 0);
 	assert(percentage <= 100);
 
-	uint64_t mem = lzma_physmem();
-
-	// If we cannot determine the amount of RAM, use the assumption
-	// defined by the configure script.
-	if (mem == 0)
-		mem = (uint64_t)(ASSUME_RAM) * 1024 * 1024;
-
-	memlimit = percentage * mem / 100;
+	memlimit = percentage * total_ram / 100;
 	return;
 }
 
@@ -87,6 +99,13 @@ hardware_memlimit_get(void)
 extern void
 hardware_init(void)
 {
+	// Get the amount of RAM. If we cannot determine it,
+	// use the assumption defined by the configure script.
+	total_ram = lzma_physmem();
+	if (total_ram == 0)
+		total_ram = (uint64_t)(ASSUME_RAM) * 1024 * 1024;
+
+	// Set the defaults.
 	hardware_memlimit_set(0);
 	hardware_threadlimit_set(0);
 	return;