[PATCH v1 26/29] virtio-mem: allow to force Big Block Mode (BBM) and set the big block size
STALE2173d
From: David Hildenbrand <hidden>
Date: 2020-10-12 12:57:14
Also in:
linux-mm, lkml
Subsystem:
the rest, virtio core, virtio mem driver · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang, Eugenio Pérez, David Hildenbrand
Revision v1 of 2 in this series.
Revisions (2)
- v1 current
- v2 [diff vs current]
Let's allow to force BBM, even if subblocks would be possible. Take care of properly calculating the first big block id, because the start address might no longer be aligned to the big block size. Also, allow to manually configure the size of Big Blocks. Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Jason Wang <redacted> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Wei Yang <redacted> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Hildenbrand <redacted> --- drivers/virtio/virtio_mem.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-)
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 4d396ef98a92..94cf44b15cbf 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c@@ -27,6 +27,16 @@ static bool unplug_online = true; module_param(unplug_online, bool, 0644); MODULE_PARM_DESC(unplug_online, "Try to unplug online memory"); +static bool force_bbm; +module_param(force_bbm, bool, 0444); +MODULE_PARM_DESC(force_bbm, + "Force Big Block Mode. Default is 0 (auto-selection)"); + +static unsigned long bbm_block_size; +module_param(bbm_block_size, ulong, 0444); +MODULE_PARM_DESC(bbm_block_size, + "Big Block size in bytes. Default is 0 (auto-detection)."); + /* * virtio-mem currently supports the following modes of operation: *
@@ -2164,7 +2174,7 @@ static int virtio_mem_init(struct virtio_mem *vm) pageblock_nr_pages) * PAGE_SIZE; sb_size = max_t(uint64_t, vm->device_block_size, sb_size); - if (sb_size < memory_block_size_bytes()) { + if (sb_size < memory_block_size_bytes() && !force_bbm) { /* SBM: At least two subblocks per Linux memory block. */ vm->in_sbm = true; vm->sbm.sb_size = sb_size;
@@ -2177,9 +2187,24 @@ static int virtio_mem_init(struct virtio_mem *vm) vm->sbm.next_mb_id = vm->sbm.first_mb_id; } else { /* BBM: At least one Linux memory block. */ - vm->bbm.bb_size = vm->device_block_size; + vm->bbm.bb_size = max_t(uint64_t, vm->device_block_size, + memory_block_size_bytes()); + + if (bbm_block_size) { + if (!is_power_of_2(bbm_block_size)) { + dev_warn(&vm->vdev->dev, + "bbm_block_size is not a power of 2"); + } else if (bbm_block_size < vm->bbm.bb_size) { + dev_warn(&vm->vdev->dev, + "bbm_block_size is too small"); + } else { + vm->bbm.bb_size = bbm_block_size; + } + } - vm->bbm.first_bb_id = virtio_mem_phys_to_bb_id(vm, vm->addr); + /* Round up to the next aligned big block */ + addr = vm->addr + vm->bbm.bb_size - 1; + vm->bbm.first_bb_id = virtio_mem_phys_to_bb_id(vm, addr); vm->bbm.next_bb_id = vm->bbm.first_bb_id; }
--
2.26.2
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