Make memory tidying less agressive, matching the numbers with memory reclaiming

doc/doxygen/chapters/40environment_variables.doxy

@@ -627,7 +627,7 @@ reclaiming pass. The default is 10%.
 \addindex __env__STARPU_MINIMUM_CLEAN_BUFFERS
 This specifies the minimum percentage of number of buffers that should be clean in GPUs
 (or in main memory, when using out of core), below which asynchronous writebacks will be
-issued. The default is 10%.
+issued. The default is 5%.
 </dd>
 
 <dt>STARPU_TARGET_CLEAN_BUFFERS</dt>
@@ -636,7 +636,7 @@ issued. The default is 10%.
 \addindex __env__STARPU_TARGET_CLEAN_BUFFERS
 This specifies the target percentage of number of buffers that should be reached in
 GPUs (or in main memory, when using out of core), when performing an asynchronous
-writeback pass. The default is 25%.
+writeback pass. The default is 10%.
 </dd>
 
 <dt>STARPU_DISK_SWAP</dt>

src/datawizard/memalloc.c

@@ -129,8 +129,8 @@ void _starpu_init_mem_chunk_lists(void)
 	}
 	minimum_p = starpu_get_env_number_default("STARPU_MINIMUM_AVAILABLE_MEM", 5);
 	target_p = starpu_get_env_number_default("STARPU_TARGET_AVAILABLE_MEM", 10);
-	minimum_clean_p = starpu_get_env_number_default("STARPU_MINIMUM_CLEAN_BUFFERS", 10);
-	target_clean_p = starpu_get_env_number_default("STARPU_TARGET_CLEAN_BUFFERS", 25);
+	minimum_clean_p = starpu_get_env_number_default("STARPU_MINIMUM_CLEAN_BUFFERS", 5);
+	target_clean_p = starpu_get_env_number_default("STARPU_TARGET_CLEAN_BUFFERS", 10);
 	limit_cpu_mem = starpu_get_env_number("STARPU_LIMIT_CPU_MEM");
 }