Re: [PATCH v1 28/29] virtio-mem: Big Block Mode (BBM) - basic memory hotunplug
On 19.10.20 05:48, Wei Yang wrote: > On Mon, Oct 12, 2020 at 02:53:22PM +0200, David Hildenbrand wrote: >> Let's try to unplug completely offline big blocks first. Then, (if >> enabled via unplug_offline) try to offline and remove whole big blocks. >> >> No locking necessary - we can deal with concurrent onlining/offlining >> just fine. >> >> Note1: This is sub-optimal and might be dangerous in some environments: we >> could end up in an infinite loop when offlining (e.g., long-term pinnings), >> similar as with DIMMs. We'll introduce safe memory hotunplug via >> fake-offlining next, and use this basic mode only when explicitly enabled. >> >> Note2: Without ZONE_MOVABLE, memory unplug will be extremely unreliable >> with bigger block sizes. >> >> Cc: "Michael S. Tsirkin" >> Cc: Jason Wang >> Cc: Pankaj Gupta >> Cc: Michal Hocko >> Cc: Oscar Salvador >> Cc: Wei Yang >> Cc: Andrew Morton >> Signed-off-by: David Hildenbrand >> --- >> drivers/virtio/virtio_mem.c | 156 +++- >> 1 file changed, 155 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c >> index 94cf44b15cbf..6bcd0acbff32 100644 >> --- a/drivers/virtio/virtio_mem.c >> +++ b/drivers/virtio/virtio_mem.c >> @@ -388,6 +388,12 @@ static int >> virtio_mem_bbm_bb_states_prepare_next_bb(struct virtio_mem *vm) >> _bb_id++) \ >> if (virtio_mem_bbm_get_bb_state(_vm, _bb_id) == _state) >> >> +#define virtio_mem_bbm_for_each_bb_rev(_vm, _bb_id, _state) \ >> +for (_bb_id = vm->bbm.next_bb_id - 1; \ >> + _bb_id >= vm->bbm.first_bb_id && _vm->bbm.bb_count[_state]; \ >> + _bb_id--) \ >> +if (virtio_mem_bbm_get_bb_state(_vm, _bb_id) == _state) >> + >> /* >> * Set the state of a memory block, taking care of the state counter. >> */ >> @@ -685,6 +691,18 @@ static int virtio_mem_sbm_remove_mb(struct virtio_mem >> *vm, unsigned long mb_id) >> return virtio_mem_remove_memory(vm, addr, size); >> } >> >> +/* >> + * See virtio_mem_remove_memory(): Try to remove all Linux memory blocks >> covered >> + * by the big block. >> + */ >> +static int virtio_mem_bbm_remove_bb(struct virtio_mem *vm, unsigned long >> bb_id) >> +{ >> +const uint64_t addr = virtio_mem_bb_id_to_phys(vm, bb_id); >> +const uint64_t size = vm->bbm.bb_size; >> + >> +return virtio_mem_remove_memory(vm, addr, size); >> +} >> + >> /* >> * Try offlining and removing memory from Linux. >> * >> @@ -731,6 +749,19 @@ static int virtio_mem_sbm_offline_and_remove_mb(struct >> virtio_mem *vm, >> return virtio_mem_offline_and_remove_memory(vm, addr, size); >> } >> >> +/* >> + * See virtio_mem_offline_and_remove_memory(): Try to offline and remove a >> + * all Linux memory blocks covered by the big block. >> + */ >> +static int virtio_mem_bbm_offline_and_remove_bb(struct virtio_mem *vm, >> +unsigned long bb_id) >> +{ >> +const uint64_t addr = virtio_mem_bb_id_to_phys(vm, bb_id); >> +const uint64_t size = vm->bbm.bb_size; >> + >> +return virtio_mem_offline_and_remove_memory(vm, addr, size); >> +} >> + >> /* >> * Trigger the workqueue so the device can perform its magic. >> */ >> @@ -1928,6 +1959,129 @@ static int virtio_mem_sbm_unplug_request(struct >> virtio_mem *vm, uint64_t diff) >> return rc; >> } >> >> +/* >> + * Try to offline and remove a big block from Linux and unplug it. Will fail >> + * with -EBUSY if some memory is busy and cannot get unplugged. >> + * >> + * Will modify the state of the memory block. Might temporarily drop the >> + * hotplug_mutex. >> + */ >> +static int virtio_mem_bbm_offline_remove_and_unplug_bb(struct virtio_mem >> *vm, >> + unsigned long bb_id) >> +{ >> +int rc; >> + >> +if (WARN_ON_ONCE(virtio_mem_bbm_get_bb_state(vm, bb_id) != >> + VIRTIO_MEM_BBM_BB_ADDED)) >> +return -EINVAL; >> + >> +rc = virtio_mem_bbm_offline_and_remove_bb(vm, bb_id); >> +if (rc) >> +return rc; >> + >> +rc = virtio_mem_bbm_unplug_bb(vm, bb_id); >> +if (rc) >> +virtio_mem_bbm_set_bb_state(vm, bb_id, >> +VIRTIO_MEM_BBM_BB_PLUGGED); >> +else >> +virtio_mem_bbm_set_bb_state(vm, bb_id, >> +VIRTIO_MEM_BBM_BB_UNUSED); >> +return rc; >> +} >> + >> +/* >> + * Try to remove a big block from Linux and unplug it. Will fail with >> + * -EBUSY if some memory is online. >> + * >> + * Will modify the state of the memory block. >> + */ >> +static int virtio_mem_bbm_remove_and_unplug_bb(struct virtio_mem *vm, >> + unsigned long bb_id) >> +{ >> +int rc; >> + >> +if (WARN_ON_ONCE(virtio_mem_bbm_get_bb_state(vm, bb_id) != >> + VIRTIO_MEM_BBM_BB_ADDED)) >> +return -EINVAL; >> + >> +rc =
Re: [PATCH v1 28/29] virtio-mem: Big Block Mode (BBM) - basic memory hotunplug
On Mon, Oct 12, 2020 at 02:53:22PM +0200, David Hildenbrand wrote: >Let's try to unplug completely offline big blocks first. Then, (if >enabled via unplug_offline) try to offline and remove whole big blocks. > >No locking necessary - we can deal with concurrent onlining/offlining >just fine. > >Note1: This is sub-optimal and might be dangerous in some environments: we >could end up in an infinite loop when offlining (e.g., long-term pinnings), >similar as with DIMMs. We'll introduce safe memory hotunplug via >fake-offlining next, and use this basic mode only when explicitly enabled. > >Note2: Without ZONE_MOVABLE, memory unplug will be extremely unreliable >with bigger block sizes. > >Cc: "Michael S. Tsirkin" >Cc: Jason Wang >Cc: Pankaj Gupta >Cc: Michal Hocko >Cc: Oscar Salvador >Cc: Wei Yang >Cc: Andrew Morton >Signed-off-by: David Hildenbrand >--- > drivers/virtio/virtio_mem.c | 156 +++- > 1 file changed, 155 insertions(+), 1 deletion(-) > >diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c >index 94cf44b15cbf..6bcd0acbff32 100644 >--- a/drivers/virtio/virtio_mem.c >+++ b/drivers/virtio/virtio_mem.c >@@ -388,6 +388,12 @@ static int >virtio_mem_bbm_bb_states_prepare_next_bb(struct virtio_mem *vm) >_bb_id++) \ > if (virtio_mem_bbm_get_bb_state(_vm, _bb_id) == _state) > >+#define virtio_mem_bbm_for_each_bb_rev(_vm, _bb_id, _state) \ >+ for (_bb_id = vm->bbm.next_bb_id - 1; \ >+ _bb_id >= vm->bbm.first_bb_id && _vm->bbm.bb_count[_state]; \ >+ _bb_id--) \ >+ if (virtio_mem_bbm_get_bb_state(_vm, _bb_id) == _state) >+ > /* > * Set the state of a memory block, taking care of the state counter. > */ >@@ -685,6 +691,18 @@ static int virtio_mem_sbm_remove_mb(struct virtio_mem >*vm, unsigned long mb_id) > return virtio_mem_remove_memory(vm, addr, size); > } > >+/* >+ * See virtio_mem_remove_memory(): Try to remove all Linux memory blocks >covered >+ * by the big block. >+ */ >+static int virtio_mem_bbm_remove_bb(struct virtio_mem *vm, unsigned long >bb_id) >+{ >+ const uint64_t addr = virtio_mem_bb_id_to_phys(vm, bb_id); >+ const uint64_t size = vm->bbm.bb_size; >+ >+ return virtio_mem_remove_memory(vm, addr, size); >+} >+ > /* > * Try offlining and removing memory from Linux. > * >@@ -731,6 +749,19 @@ static int virtio_mem_sbm_offline_and_remove_mb(struct >virtio_mem *vm, > return virtio_mem_offline_and_remove_memory(vm, addr, size); > } > >+/* >+ * See virtio_mem_offline_and_remove_memory(): Try to offline and remove a >+ * all Linux memory blocks covered by the big block. >+ */ >+static int virtio_mem_bbm_offline_and_remove_bb(struct virtio_mem *vm, >+ unsigned long bb_id) >+{ >+ const uint64_t addr = virtio_mem_bb_id_to_phys(vm, bb_id); >+ const uint64_t size = vm->bbm.bb_size; >+ >+ return virtio_mem_offline_and_remove_memory(vm, addr, size); >+} >+ > /* > * Trigger the workqueue so the device can perform its magic. > */ >@@ -1928,6 +1959,129 @@ static int virtio_mem_sbm_unplug_request(struct >virtio_mem *vm, uint64_t diff) > return rc; > } > >+/* >+ * Try to offline and remove a big block from Linux and unplug it. Will fail >+ * with -EBUSY if some memory is busy and cannot get unplugged. >+ * >+ * Will modify the state of the memory block. Might temporarily drop the >+ * hotplug_mutex. >+ */ >+static int virtio_mem_bbm_offline_remove_and_unplug_bb(struct virtio_mem *vm, >+ unsigned long bb_id) >+{ >+ int rc; >+ >+ if (WARN_ON_ONCE(virtio_mem_bbm_get_bb_state(vm, bb_id) != >+ VIRTIO_MEM_BBM_BB_ADDED)) >+ return -EINVAL; >+ >+ rc = virtio_mem_bbm_offline_and_remove_bb(vm, bb_id); >+ if (rc) >+ return rc; >+ >+ rc = virtio_mem_bbm_unplug_bb(vm, bb_id); >+ if (rc) >+ virtio_mem_bbm_set_bb_state(vm, bb_id, >+ VIRTIO_MEM_BBM_BB_PLUGGED); >+ else >+ virtio_mem_bbm_set_bb_state(vm, bb_id, >+ VIRTIO_MEM_BBM_BB_UNUSED); >+ return rc; >+} >+ >+/* >+ * Try to remove a big block from Linux and unplug it. Will fail with >+ * -EBUSY if some memory is online. >+ * >+ * Will modify the state of the memory block. >+ */ >+static int virtio_mem_bbm_remove_and_unplug_bb(struct virtio_mem *vm, >+ unsigned long bb_id) >+{ >+ int rc; >+ >+ if (WARN_ON_ONCE(virtio_mem_bbm_get_bb_state(vm, bb_id) != >+ VIRTIO_MEM_BBM_BB_ADDED)) >+ return -EINVAL; >+ >+ rc = virtio_mem_bbm_remove_bb(vm, bb_id); >+ if (rc) >+ return -EBUSY; >+ >+ rc = virtio_mem_bbm_unplug_bb(vm, bb_id); >+ if (rc) >+ virtio_mem_bbm_set_bb_state(vm, bb_id, >+
[PATCH v1 28/29] virtio-mem: Big Block Mode (BBM) - basic memory hotunplug
Let's try to unplug completely offline big blocks first. Then, (if enabled via unplug_offline) try to offline and remove whole big blocks. No locking necessary - we can deal with concurrent onlining/offlining just fine. Note1: This is sub-optimal and might be dangerous in some environments: we could end up in an infinite loop when offlining (e.g., long-term pinnings), similar as with DIMMs. We'll introduce safe memory hotunplug via fake-offlining next, and use this basic mode only when explicitly enabled. Note2: Without ZONE_MOVABLE, memory unplug will be extremely unreliable with bigger block sizes. Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Pankaj Gupta Cc: Michal Hocko Cc: Oscar Salvador Cc: Wei Yang Cc: Andrew Morton Signed-off-by: David Hildenbrand --- drivers/virtio/virtio_mem.c | 156 +++- 1 file changed, 155 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index 94cf44b15cbf..6bcd0acbff32 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -388,6 +388,12 @@ static int virtio_mem_bbm_bb_states_prepare_next_bb(struct virtio_mem *vm) _bb_id++) \ if (virtio_mem_bbm_get_bb_state(_vm, _bb_id) == _state) +#define virtio_mem_bbm_for_each_bb_rev(_vm, _bb_id, _state) \ + for (_bb_id = vm->bbm.next_bb_id - 1; \ +_bb_id >= vm->bbm.first_bb_id && _vm->bbm.bb_count[_state]; \ +_bb_id--) \ + if (virtio_mem_bbm_get_bb_state(_vm, _bb_id) == _state) + /* * Set the state of a memory block, taking care of the state counter. */ @@ -685,6 +691,18 @@ static int virtio_mem_sbm_remove_mb(struct virtio_mem *vm, unsigned long mb_id) return virtio_mem_remove_memory(vm, addr, size); } +/* + * See virtio_mem_remove_memory(): Try to remove all Linux memory blocks covered + * by the big block. + */ +static int virtio_mem_bbm_remove_bb(struct virtio_mem *vm, unsigned long bb_id) +{ + const uint64_t addr = virtio_mem_bb_id_to_phys(vm, bb_id); + const uint64_t size = vm->bbm.bb_size; + + return virtio_mem_remove_memory(vm, addr, size); +} + /* * Try offlining and removing memory from Linux. * @@ -731,6 +749,19 @@ static int virtio_mem_sbm_offline_and_remove_mb(struct virtio_mem *vm, return virtio_mem_offline_and_remove_memory(vm, addr, size); } +/* + * See virtio_mem_offline_and_remove_memory(): Try to offline and remove a + * all Linux memory blocks covered by the big block. + */ +static int virtio_mem_bbm_offline_and_remove_bb(struct virtio_mem *vm, + unsigned long bb_id) +{ + const uint64_t addr = virtio_mem_bb_id_to_phys(vm, bb_id); + const uint64_t size = vm->bbm.bb_size; + + return virtio_mem_offline_and_remove_memory(vm, addr, size); +} + /* * Trigger the workqueue so the device can perform its magic. */ @@ -1928,6 +1959,129 @@ static int virtio_mem_sbm_unplug_request(struct virtio_mem *vm, uint64_t diff) return rc; } +/* + * Try to offline and remove a big block from Linux and unplug it. Will fail + * with -EBUSY if some memory is busy and cannot get unplugged. + * + * Will modify the state of the memory block. Might temporarily drop the + * hotplug_mutex. + */ +static int virtio_mem_bbm_offline_remove_and_unplug_bb(struct virtio_mem *vm, + unsigned long bb_id) +{ + int rc; + + if (WARN_ON_ONCE(virtio_mem_bbm_get_bb_state(vm, bb_id) != +VIRTIO_MEM_BBM_BB_ADDED)) + return -EINVAL; + + rc = virtio_mem_bbm_offline_and_remove_bb(vm, bb_id); + if (rc) + return rc; + + rc = virtio_mem_bbm_unplug_bb(vm, bb_id); + if (rc) + virtio_mem_bbm_set_bb_state(vm, bb_id, + VIRTIO_MEM_BBM_BB_PLUGGED); + else + virtio_mem_bbm_set_bb_state(vm, bb_id, + VIRTIO_MEM_BBM_BB_UNUSED); + return rc; +} + +/* + * Try to remove a big block from Linux and unplug it. Will fail with + * -EBUSY if some memory is online. + * + * Will modify the state of the memory block. + */ +static int virtio_mem_bbm_remove_and_unplug_bb(struct virtio_mem *vm, + unsigned long bb_id) +{ + int rc; + + if (WARN_ON_ONCE(virtio_mem_bbm_get_bb_state(vm, bb_id) != +VIRTIO_MEM_BBM_BB_ADDED)) + return -EINVAL; + + rc = virtio_mem_bbm_remove_bb(vm, bb_id); + if (rc) + return -EBUSY; + + rc = virtio_mem_bbm_unplug_bb(vm, bb_id); + if (rc) + virtio_mem_bbm_set_bb_state(vm, bb_id, + VIRTIO_MEM_BBM_BB_PLUGGED); + else + virtio_mem_bbm_set_bb_state(vm, bb_id, +