From 562e08cd249f98af3a3e0845998f3b27b56b0067 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 7 May 2020 16:01:37 +0200 Subject: [PATCH] virtio-mem: Unplug subblocks right-to-left We unplug blocks right-to-left, let's also unplug subblocks within a block right-to-left. Cc: "Michael S. Tsirkin" Cc: Pankaj Gupta Signed-off-by: David Hildenbrand Link: https://lore.kernel.org/r/20200507140139.17083-14-david@redhat.com Signed-off-by: Michael S. Tsirkin --- drivers/virtio/virtio_mem.c | 38 ++++++++++++++++--------------------- 1 file changed, 16 insertions(+), 22 deletions(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index 8dd57b61b09b..a719e1a04ac7 100644 --- a/drivers/virtio/virtio_mem.c +++ b/drivers/virtio/virtio_mem.c @@ -353,18 +353,6 @@ static bool virtio_mem_mb_test_sb_unplugged(struct virtio_mem *vm, 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. - */ -static int virtio_mem_mb_first_plugged_sb(struct virtio_mem *vm, - unsigned long mb_id) -{ - const int bit = (mb_id - vm->first_mb_id) * vm->nb_sb_per_mb; - - return find_next_bit(vm->sb_bitmap, bit + vm->nb_sb_per_mb, bit) - bit; -} - /* * Find the first unplugged subblock. Returns vm->nb_sb_per_mb in case there is * none. @@ -1016,21 +1004,27 @@ static int virtio_mem_mb_unplug_any_sb(struct virtio_mem *vm, int sb_id, count; int rc; + sb_id = vm->nb_sb_per_mb - 1; while (*nb_sb) { - sb_id = virtio_mem_mb_first_plugged_sb(vm, mb_id); - if (sb_id >= vm->nb_sb_per_mb) + /* Find the next candidate subblock */ + while (sb_id >= 0 && + virtio_mem_mb_test_sb_unplugged(vm, mb_id, sb_id, 1)) + sb_id--; + if (sb_id < 0) break; + /* Try to unplug multiple subblocks at a time */ count = 1; - while (count < *nb_sb && - sb_id + count < vm->nb_sb_per_mb && - virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id + count, - 1)) + while (count < *nb_sb && sb_id > 0 && + virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id - 1, 1)) { count++; + sb_id--; + } rc = virtio_mem_mb_unplug_sb(vm, mb_id, sb_id, count); if (rc) return rc; *nb_sb -= count; + sb_id--; } return 0; @@ -1337,12 +1331,12 @@ static int virtio_mem_mb_unplug_any_sb_online(struct virtio_mem *vm, * we should sense via something like is_mem_section_removable() * first if it makes sense to go ahead any try to allocate. */ - for (sb_id = 0; sb_id < vm->nb_sb_per_mb && *nb_sb; sb_id++) { + for (sb_id = vm->nb_sb_per_mb - 1; sb_id >= 0 && *nb_sb; sb_id--) { /* Find the next candidate subblock */ - while (sb_id < vm->nb_sb_per_mb && + while (sb_id >= 0 && !virtio_mem_mb_test_sb_plugged(vm, mb_id, sb_id, 1)) - sb_id++; - if (sb_id >= vm->nb_sb_per_mb) + sb_id--; + if (sb_id < 0) break; start_pfn = PFN_DOWN(virtio_mem_mb_id_to_phys(mb_id) +