From: David Hildenbrand <david@redhat.com> To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, Michal Hocko <mhocko@kernel.org>, Andrew Morton <akpm@linux-foundation.org>, "Michael S . Tsirkin" <mst@redhat.com>, David Hildenbrand <david@redhat.com>, Jason Wang <jasowang@redhat.com>, Oscar Salvador <osalvador@suse.de>, Igor Mammedov <imammedo@redhat.com>, Dave Young <dyoung@redhat.com>, Dan Williams <dan.j.williams@intel.com>, Pavel Tatashin <pasha.tatashin@soleen.com>, Stefan Hajnoczi <stefanha@redhat.com>, Vlastimil Babka <vbabka@suse.cz> Subject: [PATCH v1 03/11] virtio-mem: Paravirtualized memory hotunplug part 1 Date: Mon, 2 Mar 2020 14:49:33 +0100 [thread overview] Message-ID: <20200302134941.315212-4-david@redhat.com> (raw) In-Reply-To: <20200302134941.315212-1-david@redhat.com> Unplugging subblocks of memory blocks that are offline is easy. All we have to do is watch out for concurrent onlining activity. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@kernel.org> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: David Hildenbrand <david@redhat.com> --- drivers/virtio/virtio_mem.c | 116 +++++++++++++++++++++++++++++++++++- 1 file changed, 114 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index d8da656c9145..c1fc7f9c4acf 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -120,7 +120,7 @@ struct virtio_mem { * * When this lock is held the pointers can't change, ONLINE and * OFFLINE blocks can't change the state and no subblocks will get - * plugged. + * plugged/unplugged. */ struct mutex hotplug_mutex; bool hotplug_active; @@ -277,6 +277,12 @@ static int virtio_mem_mb_state_prepare_next_mb(struct virtio_mem *vm) _mb_id++) \ if (virtio_mem_mb_get_state(_vm, _mb_id) == _state) +#define virtio_mem_for_each_mb_state_rev(_vm, _mb_id, _state) \ + for (_mb_id = _vm->next_mb_id - 1; \ + _mb_id >= _vm->first_mb_id && _vm->nb_mb_state[_state]; \ + _mb_id--) \ + if (virtio_mem_mb_get_state(_vm, _mb_id) == _state) + /* * Mark all selected subblocks plugged. * @@ -322,6 +328,19 @@ static bool virtio_mem_mb_test_sb_plugged(struct virtio_mem *vm, bit + count; } +/* + * Test if all selected subblocks are unplugged. + */ +static bool virtio_mem_mb_test_sb_unplugged(struct virtio_mem *vm, + unsigned long mb_id, int sb_id, + int count) +{ + const int bit = (mb_id - vm->first_mb_id) * vm->nb_sb_per_mb + sb_id; + + /* TODO: Helper similar to bitmap_set() */ + return find_next_bit(vm->sb_bitmap, bit + count, bit) >= bit + count; +} + /* * Find the first plugged subblock. Returns vm->nb_sb_per_mb in case there is * none. @@ -511,6 +530,9 @@ static void virtio_mem_notify_offline(struct virtio_mem *vm, BUG(); break; } + + /* trigger the workqueue, maybe we can now unplug memory. */ + virtio_mem_retry(vm); } static void virtio_mem_notify_online(struct virtio_mem *vm, unsigned long mb_id, @@ -1120,6 +1142,94 @@ static int virtio_mem_plug_request(struct virtio_mem *vm, uint64_t diff) return rc; } +/* + * Unplug the desired number of plugged subblocks of an offline memory block. + * Will fail if any subblock cannot get unplugged (instead of skipping it). + * + * Will modify the state of the memory block. Might temporarily drop the + * hotplug_mutex. + * + * Note: Can fail after some subblocks were successfully unplugged. + */ +static int virtio_mem_mb_unplug_any_sb_offline(struct virtio_mem *vm, + unsigned long mb_id, + uint64_t *nb_sb) +{ + int rc; + + rc = virtio_mem_mb_unplug_any_sb(vm, mb_id, nb_sb); + + /* some subblocks might have been unplugged even on failure */ + if (!virtio_mem_mb_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb)) + virtio_mem_mb_set_state(vm, mb_id, + VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL); + if (rc) + return rc; + + if (virtio_mem_mb_test_sb_unplugged(vm, mb_id, 0, vm->nb_sb_per_mb)) { + /* + * Remove the block from Linux - this should never fail. + * Hinder the block from getting onlined by marking it + * unplugged. Temporarily drop the mutex, so + * any pending GOING_ONLINE requests can be serviced/rejected. + */ + virtio_mem_mb_set_state(vm, mb_id, + VIRTIO_MEM_MB_STATE_UNUSED); + + mutex_unlock(&vm->hotplug_mutex); + rc = virtio_mem_mb_remove(vm, mb_id); + BUG_ON(rc); + mutex_lock(&vm->hotplug_mutex); + } + return 0; +} + +/* + * Try to unplug the requested amount of memory. + */ +static int virtio_mem_unplug_request(struct virtio_mem *vm, uint64_t diff) +{ + uint64_t nb_sb = diff / vm->subblock_size; + unsigned long mb_id; + int rc; + + if (!nb_sb) + return 0; + + /* + * We'll drop the mutex a couple of times when it is safe to do so. + * This might result in some blocks switching the state (online/offline) + * and we could miss them in this run - we will retry again later. + */ + mutex_lock(&vm->hotplug_mutex); + + /* Try to unplug subblocks of partially plugged offline blocks. */ + virtio_mem_for_each_mb_state_rev(vm, mb_id, + VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL) { + rc = virtio_mem_mb_unplug_any_sb_offline(vm, mb_id, + &nb_sb); + if (rc || !nb_sb) + goto out_unlock; + cond_resched(); + } + + /* Try to unplug subblocks of plugged offline blocks. */ + virtio_mem_for_each_mb_state_rev(vm, mb_id, + VIRTIO_MEM_MB_STATE_OFFLINE) { + rc = virtio_mem_mb_unplug_any_sb_offline(vm, mb_id, + &nb_sb); + if (rc || !nb_sb) + goto out_unlock; + cond_resched(); + } + + mutex_unlock(&vm->hotplug_mutex); + return 0; +out_unlock: + mutex_unlock(&vm->hotplug_mutex); + return rc; +} + /* * Try to unplug all blocks that couldn't be unplugged before, for example, * because the hypervisor was busy. @@ -1202,8 +1312,10 @@ static void virtio_mem_run_wq(struct work_struct *work) if (vm->requested_size > vm->plugged_size) { diff = vm->requested_size - vm->plugged_size; rc = virtio_mem_plug_request(vm, diff); + } else { + diff = vm->plugged_size - vm->requested_size; + rc = virtio_mem_unplug_request(vm, diff); } - /* TODO: try to unplug memory */ } switch (rc) { -- 2.24.1
WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com> To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, Michal Hocko <mhocko@kernel.org>, Andrew Morton <akpm@linux-foundation.org>, "Michael S . Tsirkin" <mst@redhat.com>, David Hildenbrand <david@redhat.com>, Jason Wang <jasowang@redhat.com>, Oscar Salvador <osalvador@suse.de>, Igor Mammedov <imammedo@redhat.com>, Dave Young <dyoung@redhat.com>, Dan Williams <dan.j.williams@intel.com>, Pavel Tatashin <pasha.tatashin@soleen.com>, Stefan Hajnoczi <stefanha@redhat.com>, Vlastimil Babka <vbabka@suse.cz> Subject: [virtio-dev] [PATCH v1 03/11] virtio-mem: Paravirtualized memory hotunplug part 1 Date: Mon, 2 Mar 2020 14:49:33 +0100 [thread overview] Message-ID: <20200302134941.315212-4-david@redhat.com> (raw) In-Reply-To: <20200302134941.315212-1-david@redhat.com> Unplugging subblocks of memory blocks that are offline is easy. All we have to do is watch out for concurrent onlining activity. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@kernel.org> Cc: Igor Mammedov <imammedo@redhat.com> Cc: Dave Young <dyoung@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: David Hildenbrand <david@redhat.com> --- drivers/virtio/virtio_mem.c | 116 +++++++++++++++++++++++++++++++++++- 1 file changed, 114 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index d8da656c9145..c1fc7f9c4acf 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -120,7 +120,7 @@ struct virtio_mem { * * When this lock is held the pointers can't change, ONLINE and * OFFLINE blocks can't change the state and no subblocks will get - * plugged. + * plugged/unplugged. */ struct mutex hotplug_mutex; bool hotplug_active; @@ -277,6 +277,12 @@ static int virtio_mem_mb_state_prepare_next_mb(struct virtio_mem *vm) _mb_id++) \ if (virtio_mem_mb_get_state(_vm, _mb_id) == _state) +#define virtio_mem_for_each_mb_state_rev(_vm, _mb_id, _state) \ + for (_mb_id = _vm->next_mb_id - 1; \ + _mb_id >= _vm->first_mb_id && _vm->nb_mb_state[_state]; \ + _mb_id--) \ + if (virtio_mem_mb_get_state(_vm, _mb_id) == _state) + /* * Mark all selected subblocks plugged. * @@ -322,6 +328,19 @@ static bool virtio_mem_mb_test_sb_plugged(struct virtio_mem *vm, bit + count; } +/* + * Test if all selected subblocks are unplugged. + */ +static bool virtio_mem_mb_test_sb_unplugged(struct virtio_mem *vm, + unsigned long mb_id, int sb_id, + int count) +{ + const int bit = (mb_id - vm->first_mb_id) * vm->nb_sb_per_mb + sb_id; + + /* TODO: Helper similar to bitmap_set() */ + return find_next_bit(vm->sb_bitmap, bit + count, bit) >= bit + count; +} + /* * Find the first plugged subblock. Returns vm->nb_sb_per_mb in case there is * none. @@ -511,6 +530,9 @@ static void virtio_mem_notify_offline(struct virtio_mem *vm, BUG(); break; } + + /* trigger the workqueue, maybe we can now unplug memory. */ + virtio_mem_retry(vm); } static void virtio_mem_notify_online(struct virtio_mem *vm, unsigned long mb_id, @@ -1120,6 +1142,94 @@ static int virtio_mem_plug_request(struct virtio_mem *vm, uint64_t diff) return rc; } +/* + * Unplug the desired number of plugged subblocks of an offline memory block. + * Will fail if any subblock cannot get unplugged (instead of skipping it). + * + * Will modify the state of the memory block. Might temporarily drop the + * hotplug_mutex. + * + * Note: Can fail after some subblocks were successfully unplugged. + */ +static int virtio_mem_mb_unplug_any_sb_offline(struct virtio_mem *vm, + unsigned long mb_id, + uint64_t *nb_sb) +{ + int rc; + + rc = virtio_mem_mb_unplug_any_sb(vm, mb_id, nb_sb); + + /* some subblocks might have been unplugged even on failure */ + if (!virtio_mem_mb_test_sb_plugged(vm, mb_id, 0, vm->nb_sb_per_mb)) + virtio_mem_mb_set_state(vm, mb_id, + VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL); + if (rc) + return rc; + + if (virtio_mem_mb_test_sb_unplugged(vm, mb_id, 0, vm->nb_sb_per_mb)) { + /* + * Remove the block from Linux - this should never fail. + * Hinder the block from getting onlined by marking it + * unplugged. Temporarily drop the mutex, so + * any pending GOING_ONLINE requests can be serviced/rejected. + */ + virtio_mem_mb_set_state(vm, mb_id, + VIRTIO_MEM_MB_STATE_UNUSED); + + mutex_unlock(&vm->hotplug_mutex); + rc = virtio_mem_mb_remove(vm, mb_id); + BUG_ON(rc); + mutex_lock(&vm->hotplug_mutex); + } + return 0; +} + +/* + * Try to unplug the requested amount of memory. + */ +static int virtio_mem_unplug_request(struct virtio_mem *vm, uint64_t diff) +{ + uint64_t nb_sb = diff / vm->subblock_size; + unsigned long mb_id; + int rc; + + if (!nb_sb) + return 0; + + /* + * We'll drop the mutex a couple of times when it is safe to do so. + * This might result in some blocks switching the state (online/offline) + * and we could miss them in this run - we will retry again later. + */ + mutex_lock(&vm->hotplug_mutex); + + /* Try to unplug subblocks of partially plugged offline blocks. */ + virtio_mem_for_each_mb_state_rev(vm, mb_id, + VIRTIO_MEM_MB_STATE_OFFLINE_PARTIAL) { + rc = virtio_mem_mb_unplug_any_sb_offline(vm, mb_id, + &nb_sb); + if (rc || !nb_sb) + goto out_unlock; + cond_resched(); + } + + /* Try to unplug subblocks of plugged offline blocks. */ + virtio_mem_for_each_mb_state_rev(vm, mb_id, + VIRTIO_MEM_MB_STATE_OFFLINE) { + rc = virtio_mem_mb_unplug_any_sb_offline(vm, mb_id, + &nb_sb); + if (rc || !nb_sb) + goto out_unlock; + cond_resched(); + } + + mutex_unlock(&vm->hotplug_mutex); + return 0; +out_unlock: + mutex_unlock(&vm->hotplug_mutex); + return rc; +} + /* * Try to unplug all blocks that couldn't be unplugged before, for example, * because the hypervisor was busy. @@ -1202,8 +1312,10 @@ static void virtio_mem_run_wq(struct work_struct *work) if (vm->requested_size > vm->plugged_size) { diff = vm->requested_size - vm->plugged_size; rc = virtio_mem_plug_request(vm, diff); + } else { + diff = vm->plugged_size - vm->requested_size; + rc = virtio_mem_unplug_request(vm, diff); } - /* TODO: try to unplug memory */ } switch (rc) { -- 2.24.1 --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org
next prev parent reply other threads:[~2020-03-02 13:51 UTC|newest] Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-02 13:49 [PATCH v1 00/11] virtio-mem: paravirtualized memory David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-02 13:49 ` David Hildenbrand 2020-03-02 13:49 ` [PATCH v1 01/11] ACPI: NUMA: export pxm_to_node David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-02 14:03 ` Michal Hocko 2020-03-02 14:09 ` David Hildenbrand 2020-03-02 14:09 ` [virtio-dev] " David Hildenbrand 2020-03-02 13:49 ` [PATCH v1 02/11] virtio-mem: Paravirtualized memory hotplug David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-03 2:24 ` kbuild test robot 2020-03-03 2:24 ` kbuild test robot 2020-03-03 2:24 ` kbuild test robot 2020-03-03 8:06 ` David Hildenbrand 2020-03-03 8:06 ` [virtio-dev] " David Hildenbrand 2020-03-03 8:06 ` David Hildenbrand 2020-03-02 13:49 ` David Hildenbrand [this message] 2020-03-02 13:49 ` [virtio-dev] [PATCH v1 03/11] virtio-mem: Paravirtualized memory hotunplug part 1 David Hildenbrand 2020-03-02 13:49 ` [PATCH v1 04/11] mm: Export alloc_contig_range() / free_contig_range() David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-02 14:05 ` Michal Hocko 2020-03-02 14:17 ` David Hildenbrand 2020-03-02 14:17 ` [virtio-dev] " David Hildenbrand 2020-03-02 13:49 ` [PATCH v1 05/11] virtio-mem: Paravirtualized memory hotunplug part 2 David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-02 13:49 ` [PATCH v1 06/11] mm: Allow to offline unmovable PageOffline() pages via MEM_GOING_OFFLINE David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-02 17:40 ` Alexander Duyck 2020-03-02 17:40 ` [virtio-dev] " Alexander Duyck 2020-03-02 17:40 ` Alexander Duyck 2020-03-02 17:40 ` Alexander Duyck 2020-03-02 18:41 ` David Hildenbrand 2020-03-02 18:41 ` [virtio-dev] " David Hildenbrand 2020-03-10 11:47 ` Michal Hocko 2020-03-10 11:47 ` Michal Hocko 2020-03-10 11:48 ` David Hildenbrand 2020-03-10 11:48 ` [virtio-dev] " David Hildenbrand 2020-03-10 11:48 ` David Hildenbrand 2020-03-02 13:49 ` [PATCH v1 07/11] virtio-mem: Allow to offline partially unplugged memory blocks David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-10 11:43 ` Michal Hocko 2020-03-10 11:46 ` David Hildenbrand 2020-03-10 11:46 ` [virtio-dev] " David Hildenbrand 2020-03-10 11:59 ` Michal Hocko 2020-03-10 12:09 ` David Hildenbrand 2020-03-10 12:09 ` [virtio-dev] " David Hildenbrand 2020-03-02 13:49 ` [PATCH v1 08/11] mm/memory_hotplug: Introduce offline_and_remove_memory() David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-02 14:27 ` Michal Hocko 2020-03-02 13:49 ` [PATCH v1 09/11] virtio-mem: Offline and remove completely unplugged memory blocks David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-02 13:49 ` [PATCH v1 10/11] virtio-mem: Better retry handling David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-02 13:49 ` [PATCH v1 11/11] MAINTAINERS: Add myself as virtio-mem maintainer David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " David Hildenbrand 2020-03-02 18:15 ` [PATCH v1 00/11] virtio-mem: paravirtualized memory David Hildenbrand 2020-03-02 18:15 ` [virtio-dev] " David Hildenbrand 2020-03-02 18:15 ` David Hildenbrand 2020-03-02 18:29 ` Michal Hocko 2020-03-02 18:29 ` Michal Hocko 2020-03-02 18:41 ` David Hildenbrand 2020-03-02 18:41 ` [virtio-dev] " David Hildenbrand 2020-03-02 18:41 ` David Hildenbrand
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