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 07/11] virtio-mem: Allow to offline partially unplugged memory blocks Date: Mon, 2 Mar 2020 14:49:37 +0100 [thread overview] Message-ID: <20200302134941.315212-8-david@redhat.com> (raw) In-Reply-To: <20200302134941.315212-1-david@redhat.com> Dropping the reference count of PageOffline() pages allows offlining code to skip them. However, we also have to convert PG_reserved to another flag - let's use PG_dirty - so has_unmovable_pages() will properly handle them. PG_reserved pages get detected as unmovable right away. We need the flag to see if we are onlining pages the first time, or if we allocated them via alloc_contig_range(). Properly take care of offlining code also modifying the stats and special handling in case the driver gets unloaded. 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 | 64 ++++++++++++++++++++++++++++++++++++- 1 file changed, 63 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index 5b26d57be551..2916f8b970fa 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -570,6 +570,53 @@ static void virtio_mem_notify_online(struct virtio_mem *vm, unsigned long mb_id, virtio_mem_retry(vm); } +static void virtio_mem_notify_going_offline(struct virtio_mem *vm, + unsigned long mb_id) +{ + const unsigned long nr_pages = PFN_DOWN(vm->subblock_size); + unsigned long pfn; + int sb_id, i; + + for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) { + if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1)) + continue; + /* + * Drop our reference to the pages so the memory can get + * offlined and add the unplugged pages to the managed + * page counters (so offlining code can correctly subtract + * them again). + */ + pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) + + sb_id * vm->subblock_size); + adjust_managed_page_count(pfn_to_page(pfn), nr_pages); + for (i = 0; i < nr_pages; i++) + page_ref_dec(pfn_to_page(pfn + i)); + } +} + +static void virtio_mem_notify_cancel_offline(struct virtio_mem *vm, + unsigned long mb_id) +{ + const unsigned long nr_pages = PFN_DOWN(vm->subblock_size); + unsigned long pfn; + int sb_id, i; + + for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) { + if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1)) + continue; + /* + * Get the reference we dropped when going offline and + * subtract the unplugged pages from the managed page + * counters. + */ + pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) + + sb_id * vm->subblock_size); + adjust_managed_page_count(pfn_to_page(pfn), -nr_pages); + for (i = 0; i < nr_pages; i++) + page_ref_inc(pfn_to_page(pfn + i)); + } +} + /* * This callback will either be called synchronously from add_memory() or * asynchronously (e.g., triggered via user space). We have to be careful @@ -616,6 +663,7 @@ static int virtio_mem_memory_notifier_cb(struct notifier_block *nb, break; } vm->hotplug_active = true; + virtio_mem_notify_going_offline(vm, mb_id); break; case MEM_GOING_ONLINE: mutex_lock(&vm->hotplug_mutex); @@ -640,6 +688,12 @@ static int virtio_mem_memory_notifier_cb(struct notifier_block *nb, mutex_unlock(&vm->hotplug_mutex); break; case MEM_CANCEL_OFFLINE: + if (!vm->hotplug_active) + break; + virtio_mem_notify_cancel_offline(vm, mb_id); + vm->hotplug_active = false; + mutex_unlock(&vm->hotplug_mutex); + break; case MEM_CANCEL_ONLINE: if (!vm->hotplug_active) break; @@ -666,8 +720,11 @@ static void virtio_mem_set_fake_offline(unsigned long pfn, struct page *page = pfn_to_page(pfn); __SetPageOffline(page); - if (!onlined) + if (!onlined) { SetPageDirty(page); + /* FIXME: remove after cleanups */ + ClearPageReserved(page); + } } } @@ -1717,6 +1774,11 @@ static void virtio_mem_remove(struct virtio_device *vdev) rc = virtio_mem_mb_remove(vm, mb_id); BUG_ON(rc); } + /* + * After we unregistered our callbacks, user space can no longer + * offline partially plugged online memory blocks. No need to worry + * about them. + */ /* unregister callbacks */ unregister_virtio_mem_device(vm); -- 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 07/11] virtio-mem: Allow to offline partially unplugged memory blocks Date: Mon, 2 Mar 2020 14:49:37 +0100 [thread overview] Message-ID: <20200302134941.315212-8-david@redhat.com> (raw) In-Reply-To: <20200302134941.315212-1-david@redhat.com> Dropping the reference count of PageOffline() pages allows offlining code to skip them. However, we also have to convert PG_reserved to another flag - let's use PG_dirty - so has_unmovable_pages() will properly handle them. PG_reserved pages get detected as unmovable right away. We need the flag to see if we are onlining pages the first time, or if we allocated them via alloc_contig_range(). Properly take care of offlining code also modifying the stats and special handling in case the driver gets unloaded. 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 | 64 ++++++++++++++++++++++++++++++++++++- 1 file changed, 63 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index 5b26d57be551..2916f8b970fa 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -570,6 +570,53 @@ static void virtio_mem_notify_online(struct virtio_mem *vm, unsigned long mb_id, virtio_mem_retry(vm); } +static void virtio_mem_notify_going_offline(struct virtio_mem *vm, + unsigned long mb_id) +{ + const unsigned long nr_pages = PFN_DOWN(vm->subblock_size); + unsigned long pfn; + int sb_id, i; + + for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) { + if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1)) + continue; + /* + * Drop our reference to the pages so the memory can get + * offlined and add the unplugged pages to the managed + * page counters (so offlining code can correctly subtract + * them again). + */ + pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) + + sb_id * vm->subblock_size); + adjust_managed_page_count(pfn_to_page(pfn), nr_pages); + for (i = 0; i < nr_pages; i++) + page_ref_dec(pfn_to_page(pfn + i)); + } +} + +static void virtio_mem_notify_cancel_offline(struct virtio_mem *vm, + unsigned long mb_id) +{ + const unsigned long nr_pages = PFN_DOWN(vm->subblock_size); + unsigned long pfn; + int sb_id, i; + + for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) { + if (virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1)) + continue; + /* + * Get the reference we dropped when going offline and + * subtract the unplugged pages from the managed page + * counters. + */ + pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) + + sb_id * vm->subblock_size); + adjust_managed_page_count(pfn_to_page(pfn), -nr_pages); + for (i = 0; i < nr_pages; i++) + page_ref_inc(pfn_to_page(pfn + i)); + } +} + /* * This callback will either be called synchronously from add_memory() or * asynchronously (e.g., triggered via user space). We have to be careful @@ -616,6 +663,7 @@ static int virtio_mem_memory_notifier_cb(struct notifier_block *nb, break; } vm->hotplug_active = true; + virtio_mem_notify_going_offline(vm, mb_id); break; case MEM_GOING_ONLINE: mutex_lock(&vm->hotplug_mutex); @@ -640,6 +688,12 @@ static int virtio_mem_memory_notifier_cb(struct notifier_block *nb, mutex_unlock(&vm->hotplug_mutex); break; case MEM_CANCEL_OFFLINE: + if (!vm->hotplug_active) + break; + virtio_mem_notify_cancel_offline(vm, mb_id); + vm->hotplug_active = false; + mutex_unlock(&vm->hotplug_mutex); + break; case MEM_CANCEL_ONLINE: if (!vm->hotplug_active) break; @@ -666,8 +720,11 @@ static void virtio_mem_set_fake_offline(unsigned long pfn, struct page *page = pfn_to_page(pfn); __SetPageOffline(page); - if (!onlined) + if (!onlined) { SetPageDirty(page); + /* FIXME: remove after cleanups */ + ClearPageReserved(page); + } } } @@ -1717,6 +1774,11 @@ static void virtio_mem_remove(struct virtio_device *vdev) rc = virtio_mem_mb_remove(vm, mb_id); BUG_ON(rc); } + /* + * After we unregistered our callbacks, user space can no longer + * offline partially plugged online memory blocks. No need to worry + * about them. + */ /* unregister callbacks */ unregister_virtio_mem_device(vm); -- 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 13:52 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 ` [PATCH v1 03/11] virtio-mem: Paravirtualized memory hotunplug part 1 David Hildenbrand 2020-03-02 13:49 ` [virtio-dev] " 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 ` David Hildenbrand [this message] 2020-03-02 13:49 ` [virtio-dev] [PATCH v1 07/11] virtio-mem: Allow to offline partially unplugged memory blocks 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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