virtio-mem: Unplug subblocks right-to-left (562e08cd) · Commits · 戴 / test

drivers/virtio/virtio_mem.c

+16 −22

Original line number	Diff line number	Diff line
		@@ -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) +

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