diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt index 97c4b3284329..b716d33912d8 100644 --- a/Documentation/sysctl/vm.txt +++ b/Documentation/sysctl/vm.txt @@ -90,6 +90,10 @@ will itself start writeback. If dirty_bytes is written, dirty_ratio becomes a function of its value (dirty_bytes / the amount of dirtyable system memory). +Note: the minimum value allowed for dirty_bytes is two pages (in bytes); any +value lower than this limit will be ignored and the old configuration will be +retained. + ============================================================== dirty_expire_centisecs diff --git a/kernel/sysctl.c b/kernel/sysctl.c index e3d2c7dd59b9..ea78fa101ad6 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -103,6 +103,9 @@ static unsigned long one_ul = 1; static int one_hundred = 100; static int one_thousand = 1000; +/* this is needed for the proc_doulongvec_minmax of vm_dirty_bytes */ +static unsigned long dirty_bytes_min = 2 * PAGE_SIZE; + /* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */ static int maxolduid = 65535; static int minolduid; @@ -1006,7 +1009,7 @@ static struct ctl_table vm_table[] = { .mode = 0644, .proc_handler = &dirty_bytes_handler, .strategy = &sysctl_intvec, - .extra1 = &one_ul, + .extra1 = &dirty_bytes_min, }, { .procname = "dirty_writeback_centisecs",