From: David Hildenbrand <david@redhat.com> To: linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org, linux-mm@kvack.org, "Michael S . Tsirkin" <mst@redhat.com>, David Hildenbrand <david@redhat.com>, Wei Yang <richard.weiyang@linux.alibaba.com>, Jason Wang <jasowang@redhat.com>, Pankaj Gupta <pankaj.gupta.linux@gmail.com>, Michal Hocko <mhocko@kernel.org>, Oscar Salvador <osalvador@suse.de>, Andrew Morton <akpm@linux-foundation.org> Subject: [PATCH v2 27/29] mm/memory_hotplug: extend offline_and_remove_memory() to handle more than one memory block Date: Thu, 12 Nov 2020 14:38:13 +0100 [thread overview] Message-ID: <20201112133815.13332-28-david@redhat.com> (raw) In-Reply-To: <20201112133815.13332-1-david@redhat.com> virtio-mem soon wants to use offline_and_remove_memory() memory that exceeds a single Linux memory block (memory_block_size_bytes()). Let's remove that restriction. Let's remember the old state and try to restore that if anything goes wrong. While re-onlining can, in general, fail, it's highly unlikely to happen (usually only when a notifier fails to allocate memory, and these are rather rare). This will be used by virtio-mem to offline+remove memory ranges that are bigger than a single memory block - for example, with a device block size of 1 GiB (e.g., gigantic pages in the hypervisor) and a Linux memory block size of 128MB. While we could compress the state into 2 bit, using 8 bit is much easier. This handling is similar, but different to acpi_scan_try_to_offline(): a) We don't try to offline twice. I am not sure if this CONFIG_MEMCG optimization is still relevant - it should only apply to ZONE_NORMAL (where we have no guarantees). If relevant, we can always add it. b) acpi_scan_try_to_offline() simply onlines all memory in case something goes wrong. It doesn't restore previous online type. Let's do that, so we won't overwrite what e.g., user space configured. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Hildenbrand <david@redhat.com> --- mm/memory_hotplug.c | 105 +++++++++++++++++++++++++++++++++++++------- 1 file changed, 89 insertions(+), 16 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b44d4c7ba73b..217080ca93e5 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1806,39 +1806,112 @@ int remove_memory(int nid, u64 start, u64 size) } EXPORT_SYMBOL_GPL(remove_memory); +static int try_offline_memory_block(struct memory_block *mem, void *arg) +{ + uint8_t online_type = MMOP_ONLINE_KERNEL; + uint8_t **online_types = arg; + struct page *page; + int rc; + + /* + * Sense the online_type via the zone of the memory block. Offlining + * with multiple zones within one memory block will be rejected + * by offlining code ... so we don't care about that. + */ + page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr)); + if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE) + online_type = MMOP_ONLINE_MOVABLE; + + rc = device_offline(&mem->dev); + /* + * Default is MMOP_OFFLINE - change it only if offlining succeeded, + * so try_reonline_memory_block() can do the right thing. + */ + if (!rc) + **online_types = online_type; + + (*online_types)++; + /* Ignore if already offline. */ + return rc < 0 ? rc : 0; +} + +static int try_reonline_memory_block(struct memory_block *mem, void *arg) +{ + uint8_t **online_types = arg; + int rc; + + if (**online_types != MMOP_OFFLINE) { + mem->online_type = **online_types; + rc = device_online(&mem->dev); + if (rc < 0) + pr_warn("%s: Failed to re-online memory: %d", + __func__, rc); + } + + /* Continue processing all remaining memory blocks. */ + (*online_types)++; + return 0; +} + /* - * Try to offline and remove a memory block. Might take a long time to - * finish in case memory is still in use. Primarily useful for memory devices - * that logically unplugged all memory (so it's no longer in use) and want to - * offline + remove the memory block. + * Try to offline and remove memory. Might take a long time to finish in case + * memory is still in use. Primarily useful for memory devices that logically + * unplugged all memory (so it's no longer in use) and want to offline + remove + * that memory. */ int offline_and_remove_memory(int nid, u64 start, u64 size) { - struct memory_block *mem; - int rc = -EINVAL; + const unsigned long mb_count = size / memory_block_size_bytes(); + uint8_t *online_types, *tmp; + int rc; if (!IS_ALIGNED(start, memory_block_size_bytes()) || - size != memory_block_size_bytes()) - return rc; + !IS_ALIGNED(size, memory_block_size_bytes()) || !size) + return -EINVAL; + + /* + * We'll remember the old online type of each memory block, so we can + * try to revert whatever we did when offlining one memory block fails + * after offlining some others succeeded. + */ + online_types = kmalloc_array(mb_count, sizeof(*online_types), + GFP_KERNEL); + if (!online_types) + return -ENOMEM; + /* + * Initialize all states to MMOP_OFFLINE, so when we abort processing in + * try_offline_memory_block(), we'll skip all unprocessed blocks in + * try_reonline_memory_block(). + */ + memset(online_types, MMOP_OFFLINE, mb_count); lock_device_hotplug(); - mem = find_memory_block(__pfn_to_section(PFN_DOWN(start))); - if (mem) - rc = device_offline(&mem->dev); - /* Ignore if the device is already offline. */ - if (rc > 0) - rc = 0; + + tmp = online_types; + rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block); /* - * In case we succeeded to offline the memory block, remove it. + * In case we succeeded to offline all memory, remove it. * This cannot fail as it cannot get onlined in the meantime. */ if (!rc) { rc = try_remove_memory(nid, start, size); - WARN_ON_ONCE(rc); + if (rc) + pr_err("%s: Failed to remove memory: %d", __func__, rc); + } + + /* + * Rollback what we did. While memory onlining might theoretically fail + * (nacked by a notifier), it barely ever happens. + */ + if (rc) { + tmp = online_types; + walk_memory_blocks(start, size, &tmp, + try_reonline_memory_block); } unlock_device_hotplug(); + kfree(online_types); return rc; } EXPORT_SYMBOL_GPL(offline_and_remove_memory); -- 2.26.2
WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com> To: linux-kernel@vger.kernel.org Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>, Wei Yang <richard.weiyang@linux.alibaba.com>, "Michael S . Tsirkin" <mst@redhat.com>, virtualization@lists.linux-foundation.org, linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>, Michal Hocko <mhocko@kernel.org>, Oscar Salvador <osalvador@suse.de> Subject: [PATCH v2 27/29] mm/memory_hotplug: extend offline_and_remove_memory() to handle more than one memory block Date: Thu, 12 Nov 2020 14:38:13 +0100 [thread overview] Message-ID: <20201112133815.13332-28-david@redhat.com> (raw) In-Reply-To: <20201112133815.13332-1-david@redhat.com> virtio-mem soon wants to use offline_and_remove_memory() memory that exceeds a single Linux memory block (memory_block_size_bytes()). Let's remove that restriction. Let's remember the old state and try to restore that if anything goes wrong. While re-onlining can, in general, fail, it's highly unlikely to happen (usually only when a notifier fails to allocate memory, and these are rather rare). This will be used by virtio-mem to offline+remove memory ranges that are bigger than a single memory block - for example, with a device block size of 1 GiB (e.g., gigantic pages in the hypervisor) and a Linux memory block size of 128MB. While we could compress the state into 2 bit, using 8 bit is much easier. This handling is similar, but different to acpi_scan_try_to_offline(): a) We don't try to offline twice. I am not sure if this CONFIG_MEMCG optimization is still relevant - it should only apply to ZONE_NORMAL (where we have no guarantees). If relevant, we can always add it. b) acpi_scan_try_to_offline() simply onlines all memory in case something goes wrong. It doesn't restore previous online type. Let's do that, so we won't overwrite what e.g., user space configured. Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <jasowang@redhat.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Hildenbrand <david@redhat.com> --- mm/memory_hotplug.c | 105 +++++++++++++++++++++++++++++++++++++------- 1 file changed, 89 insertions(+), 16 deletions(-) diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index b44d4c7ba73b..217080ca93e5 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1806,39 +1806,112 @@ int remove_memory(int nid, u64 start, u64 size) } EXPORT_SYMBOL_GPL(remove_memory); +static int try_offline_memory_block(struct memory_block *mem, void *arg) +{ + uint8_t online_type = MMOP_ONLINE_KERNEL; + uint8_t **online_types = arg; + struct page *page; + int rc; + + /* + * Sense the online_type via the zone of the memory block. Offlining + * with multiple zones within one memory block will be rejected + * by offlining code ... so we don't care about that. + */ + page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr)); + if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE) + online_type = MMOP_ONLINE_MOVABLE; + + rc = device_offline(&mem->dev); + /* + * Default is MMOP_OFFLINE - change it only if offlining succeeded, + * so try_reonline_memory_block() can do the right thing. + */ + if (!rc) + **online_types = online_type; + + (*online_types)++; + /* Ignore if already offline. */ + return rc < 0 ? rc : 0; +} + +static int try_reonline_memory_block(struct memory_block *mem, void *arg) +{ + uint8_t **online_types = arg; + int rc; + + if (**online_types != MMOP_OFFLINE) { + mem->online_type = **online_types; + rc = device_online(&mem->dev); + if (rc < 0) + pr_warn("%s: Failed to re-online memory: %d", + __func__, rc); + } + + /* Continue processing all remaining memory blocks. */ + (*online_types)++; + return 0; +} + /* - * Try to offline and remove a memory block. Might take a long time to - * finish in case memory is still in use. Primarily useful for memory devices - * that logically unplugged all memory (so it's no longer in use) and want to - * offline + remove the memory block. + * Try to offline and remove memory. Might take a long time to finish in case + * memory is still in use. Primarily useful for memory devices that logically + * unplugged all memory (so it's no longer in use) and want to offline + remove + * that memory. */ int offline_and_remove_memory(int nid, u64 start, u64 size) { - struct memory_block *mem; - int rc = -EINVAL; + const unsigned long mb_count = size / memory_block_size_bytes(); + uint8_t *online_types, *tmp; + int rc; if (!IS_ALIGNED(start, memory_block_size_bytes()) || - size != memory_block_size_bytes()) - return rc; + !IS_ALIGNED(size, memory_block_size_bytes()) || !size) + return -EINVAL; + + /* + * We'll remember the old online type of each memory block, so we can + * try to revert whatever we did when offlining one memory block fails + * after offlining some others succeeded. + */ + online_types = kmalloc_array(mb_count, sizeof(*online_types), + GFP_KERNEL); + if (!online_types) + return -ENOMEM; + /* + * Initialize all states to MMOP_OFFLINE, so when we abort processing in + * try_offline_memory_block(), we'll skip all unprocessed blocks in + * try_reonline_memory_block(). + */ + memset(online_types, MMOP_OFFLINE, mb_count); lock_device_hotplug(); - mem = find_memory_block(__pfn_to_section(PFN_DOWN(start))); - if (mem) - rc = device_offline(&mem->dev); - /* Ignore if the device is already offline. */ - if (rc > 0) - rc = 0; + + tmp = online_types; + rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block); /* - * In case we succeeded to offline the memory block, remove it. + * In case we succeeded to offline all memory, remove it. * This cannot fail as it cannot get onlined in the meantime. */ if (!rc) { rc = try_remove_memory(nid, start, size); - WARN_ON_ONCE(rc); + if (rc) + pr_err("%s: Failed to remove memory: %d", __func__, rc); + } + + /* + * Rollback what we did. While memory onlining might theoretically fail + * (nacked by a notifier), it barely ever happens. + */ + if (rc) { + tmp = online_types; + walk_memory_blocks(start, size, &tmp, + try_reonline_memory_block); } unlock_device_hotplug(); + kfree(online_types); return rc; } EXPORT_SYMBOL_GPL(offline_and_remove_memory); -- 2.26.2 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
next prev parent reply other threads:[~2020-11-12 13:40 UTC|newest] Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-12 13:37 [PATCH v2 00/29] virtio-mem: Big Block Mode (BBM) David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 01/29] virtio-mem: determine nid only once using memory_add_physaddr_to_nid() David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 02/29] virtio-mem: more precise calculation in virtio_mem_mb_state_prepare_next_mb() David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 03/29] virtio-mem: simplify MAX_ORDER - 1 / pageblock_order handling David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 04/29] virtio-mem: drop rc2 in virtio_mem_mb_plug_and_add() David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 05/29] virtio-mem: use "unsigned long" for nr_pages when fake onlining/offlining David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 06/29] virtio-mem: factor out calculation of the bit number within the subblock bitmap David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 07/29] virtio-mem: print debug messages from virtio_mem_send_*_request() David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 08/29] virtio-mem: factor out fake-offlining into virtio_mem_fake_offline() David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 09/29] virtio-mem: factor out handling of fake-offline pages in memory notifier David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 10/29] virtio-mem: retry fake-offlining via alloc_contig_range() on ZONE_MOVABLE David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 11/29] virtio-mem: generalize check for added memory David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 12/29] virtio-mem: generalize virtio_mem_owned_mb() David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:37 ` [PATCH v2 13/29] virtio-mem: generalize virtio_mem_overlaps_range() David Hildenbrand 2020-11-12 13:37 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 14/29] virtio-mem: drop last_mb_id David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 15/29] virtio-mem: don't always trigger the workqueue when offlining memory David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 16/29] virtio-mem: generalize handling when memory is getting onlined deferred David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 17/29] virito-mem: document Sub Block Mode (SBM) David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 18/29] virtio-mem: memory block states are specific to " David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 19/29] virito-mem: subblock " David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 20/29] virtio-mem: nb_sb_per_mb and subblock_size " David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 21/29] virtio-mem: memory block ids " David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 22/29] virito-mem: existing (un)plug functions " David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 23/29] virtio-mem: memory notifier callbacks " David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 24/29] virtio-mem: factor out adding/removing memory from Linux David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 25/29] virtio-mem: Big Block Mode (BBM) memory hotplug David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 26/29] virtio-mem: allow to force Big Block Mode (BBM) and set the big block size David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand [this message] 2020-11-12 13:38 ` [PATCH v2 27/29] mm/memory_hotplug: extend offline_and_remove_memory() to handle more than one memory block David Hildenbrand 2020-11-18 4:53 ` Andrew Morton 2020-11-18 4:53 ` Andrew Morton 2020-11-18 8:59 ` David Hildenbrand 2020-11-18 8:59 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 28/29] virtio-mem: Big Block Mode (BBM) - basic memory hotunplug David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-12 13:38 ` [PATCH v2 29/29] virtio-mem: Big Block Mode (BBM) - safe " David Hildenbrand 2020-11-12 13:38 ` David Hildenbrand 2020-11-18 9:00 ` [PATCH v2 00/29] virtio-mem: Big Block Mode (BBM) Michael S. Tsirkin 2020-11-18 9:00 ` Michael S. Tsirkin
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