diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 3de01edca3ea..6e3b18a8afc6 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -3014,7 +3014,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. tmem.frontswap=0|1 [KNL, XEN] Default is on (1). Disable the usage of the frontswap - API to send swap pages to the hypervisor. + API to send swap pages to the hypervisor. If disabled + the selfballooning and selfshrinking are force disabled. tmem.selfballooning=0|1 [KNL, XEN] Default is on (1). Disable the driving of swap pages diff --git a/drivers/xen/tmem.c b/drivers/xen/tmem.c index c1df0ff89878..18e8bd8fa947 100644 --- a/drivers/xen/tmem.c +++ b/drivers/xen/tmem.c @@ -403,6 +403,14 @@ static int xen_tmem_init(void) } #endif #ifdef CONFIG_XEN_SELFBALLOONING + /* + * There is no point of driving pages to the swap system if they + * aren't going anywhere in tmem universe. + */ + if (!frontswap) { + selfshrinking = false; + selfballooning = false; + } xen_selfballoon_init(selfballooning, selfshrinking); #endif return 0; diff --git a/drivers/xen/xen-selfballoon.c b/drivers/xen/xen-selfballoon.c index 5d637e2b1b9f..f70984a892aa 100644 --- a/drivers/xen/xen-selfballoon.c +++ b/drivers/xen/xen-selfballoon.c @@ -53,15 +53,12 @@ * System configuration note: Selfballooning should not be enabled on * systems without a sufficiently large swap device configured; for best * results, it is recommended that total swap be increased by the size - * of the guest memory. Also, while technically not required to be - * configured, it is highly recommended that frontswap also be configured - * and enabled when selfballooning is running. So, selfballooning - * is disabled by default if frontswap is not configured and can only - * be enabled with the "tmem.selfballooning=1" kernel boot option; similarly - * selfballooning is enabled by default if frontswap is configured and - * can be disabled with the "tmem.selfballooning=0" kernel boot option. Finally, - * when frontswap is configured,frontswap-selfshrinking can be disabled - * with the "tmem.selfshrink=0" kernel boot option. + * of the guest memory. Note, that selfballooning should be disabled by default + * if frontswap is not configured. Similarly selfballooning should be enabled + * by default if frontswap is configured and can be disabled with the + * "tmem.selfballooning=0" kernel boot option. Finally, when frontswap is + * configured, frontswap-selfshrinking can be disabled with the + * "tmem.selfshrink=0" kernel boot option. * * Selfballooning is disallowed in domain0 and force-disabled. *