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Re: [Qemu-devel] [PATCH 23/31] ram: Move migration_bitmap_rcu into RAMSt
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH 23/31] ram: Move migration_bitmap_rcu into RAMState |
Date: |
Fri, 17 Mar 2017 09:51:49 +0000 |
User-agent: |
Mutt/1.8.0 (2017-02-23) |
* Juan Quintela (address@hidden) wrote:
> Once there, rename the type to be shorter.
>
> Signed-off-by: Juan Quintela <address@hidden>
> ---
> migration/ram.c | 79
> ++++++++++++++++++++++++++++++---------------------------
> 1 file changed, 42 insertions(+), 37 deletions(-)
>
> diff --git a/migration/ram.c b/migration/ram.c
> index c14293c..d39d185 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -132,6 +132,19 @@ out:
> return ret;
> }
>
> +struct RAMBitmap {
> + struct rcu_head rcu;
> + /* Main migration bitmap */
> + unsigned long *bmap;
> + /* bitmap of pages that haven't been sent even once
> + * only maintained and used in postcopy at the moment
> + * where it's used to send the dirtymap at the start
> + * of the postcopy phase
> + */
> + unsigned long *unsentmap;
> +};
> +typedef struct RAMBitmap RAMBitmap;
> +
I'm OK with this; although I can see the idea of naming it BitmapRcu,
given that the actual bmap is inside that and most of the rest of the type
is just the rcu wrapper.
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
> /* State of RAM for migration */
> struct RAMState {
> /* Last block that we have visited searching for dirty pages */
> @@ -180,6 +193,8 @@ struct RAMState {
> uint64_t migration_dirty_pages;
> /* protects modification of the bitmap */
> QemuMutex bitmap_mutex;
> + /* Ram Bitmap protected by RCU */
> + RAMBitmap *ram_bitmap;
> };
> typedef struct RAMState RAMState;
>
> @@ -236,18 +251,6 @@ struct PageSearchStatus {
> };
> typedef struct PageSearchStatus PageSearchStatus;
>
> -static struct BitmapRcu {
> - struct rcu_head rcu;
> - /* Main migration bitmap */
> - unsigned long *bmap;
> - /* bitmap of pages that haven't been sent even once
> - * only maintained and used in postcopy at the moment
> - * where it's used to send the dirtymap at the start
> - * of the postcopy phase
> - */
> - unsigned long *unsentmap;
> -} *migration_bitmap_rcu;
> -
> struct CompressParam {
> bool done;
> bool quit;
> @@ -554,7 +557,7 @@ ram_addr_t migration_bitmap_find_dirty(RAMState *rs,
> RAMBlock *rb,
>
> unsigned long next;
>
> - bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
> + bitmap = atomic_rcu_read(&rs->ram_bitmap)->bmap;
> if (rs->ram_bulk_stage && nr > base) {
> next = nr + 1;
> } else {
> @@ -569,7 +572,7 @@ static inline bool migration_bitmap_clear_dirty(RAMState
> *rs, ram_addr_t addr)
> {
> bool ret;
> int nr = addr >> TARGET_PAGE_BITS;
> - unsigned long *bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
> + unsigned long *bitmap = atomic_rcu_read(&rs->ram_bitmap)->bmap;
>
> ret = test_and_clear_bit(nr, bitmap);
>
> @@ -583,7 +586,7 @@ static void migration_bitmap_sync_range(RAMState *rs,
> ram_addr_t start,
> ram_addr_t length)
> {
> unsigned long *bitmap;
> - bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
> + bitmap = atomic_rcu_read(&rs->ram_bitmap)->bmap;
> rs-> migration_dirty_pages +=
> cpu_physical_memory_sync_dirty_bitmap(bitmap, start, length);
> }
> @@ -1115,14 +1118,14 @@ static bool get_queued_page(RAMState *rs,
> MigrationState *ms, PageSearchStatus *
> */
> if (block) {
> unsigned long *bitmap;
> - bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
> + bitmap = atomic_rcu_read(&rs->ram_bitmap)->bmap;
> dirty = test_bit(*ram_addr_abs >> TARGET_PAGE_BITS, bitmap);
> if (!dirty) {
> trace_get_queued_page_not_dirty(
> block->idstr, (uint64_t)offset,
> (uint64_t)*ram_addr_abs,
> test_bit(*ram_addr_abs >> TARGET_PAGE_BITS,
> - atomic_rcu_read(&migration_bitmap_rcu)->unsentmap));
> + atomic_rcu_read(&rs->ram_bitmap)->unsentmap));
> } else {
> trace_get_queued_page(block->idstr,
> (uint64_t)offset,
> @@ -1276,7 +1279,7 @@ static int ram_save_target_page(RAMState *rs,
> MigrationState *ms, QEMUFile *f,
> if (res < 0) {
> return res;
> }
> - unsentmap = atomic_rcu_read(&migration_bitmap_rcu)->unsentmap;
> + unsentmap = atomic_rcu_read(&rs->ram_bitmap)->unsentmap;
> if (unsentmap) {
> clear_bit(dirty_ram_abs >> TARGET_PAGE_BITS, unsentmap);
> }
> @@ -1440,7 +1443,7 @@ void free_xbzrle_decoded_buf(void)
> xbzrle_decoded_buf = NULL;
> }
>
> -static void migration_bitmap_free(struct BitmapRcu *bmap)
> +static void migration_bitmap_free(struct RAMBitmap *bmap)
> {
> g_free(bmap->bmap);
> g_free(bmap->unsentmap);
> @@ -1449,11 +1452,13 @@ static void migration_bitmap_free(struct BitmapRcu
> *bmap)
>
> static void ram_migration_cleanup(void *opaque)
> {
> + RAMState *rs = opaque;
> +
> /* caller have hold iothread lock or is in a bh, so there is
> * no writing race against this migration_bitmap
> */
> - struct BitmapRcu *bitmap = migration_bitmap_rcu;
> - atomic_rcu_set(&migration_bitmap_rcu, NULL);
> + struct RAMBitmap *bitmap = rs->ram_bitmap;
> + atomic_rcu_set(&rs->ram_bitmap, NULL);
> if (bitmap) {
> memory_global_dirty_log_stop();
> call_rcu(bitmap, migration_bitmap_free, rcu);
> @@ -1488,9 +1493,9 @@ void migration_bitmap_extend(ram_addr_t old, ram_addr_t
> new)
> /* called in qemu main thread, so there is
> * no writing race against this migration_bitmap
> */
> - if (migration_bitmap_rcu) {
> - struct BitmapRcu *old_bitmap = migration_bitmap_rcu, *bitmap;
> - bitmap = g_new(struct BitmapRcu, 1);
> + if (ram_state.ram_bitmap) {
> + struct RAMBitmap *old_bitmap = ram_state.ram_bitmap, *bitmap;
> + bitmap = g_new(struct RAMBitmap, 1);
> bitmap->bmap = bitmap_new(new);
>
> /* prevent migration_bitmap content from being set bit
> @@ -1508,7 +1513,7 @@ void migration_bitmap_extend(ram_addr_t old, ram_addr_t
> new)
> */
> bitmap->unsentmap = NULL;
>
> - atomic_rcu_set(&migration_bitmap_rcu, bitmap);
> + atomic_rcu_set(&ram_state.ram_bitmap, bitmap);
> qemu_mutex_unlock(&ram_state.bitmap_mutex);
> ram_state.migration_dirty_pages += new - old;
> call_rcu(old_bitmap, migration_bitmap_free, rcu);
> @@ -1529,7 +1534,7 @@ void ram_debug_dump_bitmap(unsigned long *todump, bool
> expected)
> char linebuf[129];
>
> if (!todump) {
> - todump = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
> + todump = atomic_rcu_read(&ram_state.ram_bitmap)->bmap;
> }
>
> for (cur = 0; cur < ram_pages; cur += linelen) {
> @@ -1559,7 +1564,7 @@ void ram_debug_dump_bitmap(unsigned long *todump, bool
> expected)
> void ram_postcopy_migrated_memory_release(MigrationState *ms)
> {
> struct RAMBlock *block;
> - unsigned long *bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
> + unsigned long *bitmap = atomic_rcu_read(&ram_state.ram_bitmap)->bmap;
>
> QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
> unsigned long first = block->offset >> TARGET_PAGE_BITS;
> @@ -1591,7 +1596,7 @@ static int postcopy_send_discard_bm_ram(MigrationState
> *ms,
> unsigned long current;
> unsigned long *unsentmap;
>
> - unsentmap = atomic_rcu_read(&migration_bitmap_rcu)->unsentmap;
> + unsentmap = atomic_rcu_read(&ram_state.ram_bitmap)->unsentmap;
> for (current = start; current < end; ) {
> unsigned long one = find_next_bit(unsentmap, end, current);
>
> @@ -1680,8 +1685,8 @@ static void
> postcopy_chunk_hostpages_pass(MigrationState *ms, bool unsent_pass,
> return;
> }
>
> - bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
> - unsentmap = atomic_rcu_read(&migration_bitmap_rcu)->unsentmap;
> + bitmap = atomic_rcu_read(&ram_state.ram_bitmap)->bmap;
> + unsentmap = atomic_rcu_read(&ram_state.ram_bitmap)->unsentmap;
>
> if (unsent_pass) {
> /* Find a sent page */
> @@ -1836,7 +1841,7 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms)
> /* This should be our last sync, the src is now paused */
> migration_bitmap_sync(&ram_state);
>
> - unsentmap = atomic_rcu_read(&migration_bitmap_rcu)->unsentmap;
> + unsentmap = atomic_rcu_read(&ram_state.ram_bitmap)->unsentmap;
> if (!unsentmap) {
> /* We don't have a safe way to resize the sentmap, so
> * if the bitmap was resized it will be NULL at this
> @@ -1857,7 +1862,7 @@ int ram_postcopy_send_discard_bitmap(MigrationState *ms)
> /*
> * Update the unsentmap to be unsentmap = unsentmap | dirty
> */
> - bitmap = atomic_rcu_read(&migration_bitmap_rcu)->bmap;
> + bitmap = atomic_rcu_read(&ram_state.ram_bitmap)->bmap;
> bitmap_or(unsentmap, unsentmap, bitmap,
> last_ram_offset() >> TARGET_PAGE_BITS);
>
> @@ -1950,16 +1955,16 @@ static int ram_state_init(RAMState *rs)
> bytes_transferred = 0;
> ram_state_reset(rs);
>
> - migration_bitmap_rcu = g_new0(struct BitmapRcu, 1);
> + rs->ram_bitmap = g_new0(struct RAMBitmap, 1);
> /* Skip setting bitmap if there is no RAM */
> if (ram_bytes_total()) {
> ram_bitmap_pages = last_ram_offset() >> TARGET_PAGE_BITS;
> - migration_bitmap_rcu->bmap = bitmap_new(ram_bitmap_pages);
> - bitmap_set(migration_bitmap_rcu->bmap, 0, ram_bitmap_pages);
> + rs->ram_bitmap->bmap = bitmap_new(ram_bitmap_pages);
> + bitmap_set(rs->ram_bitmap->bmap, 0, ram_bitmap_pages);
>
> if (migrate_postcopy_ram()) {
> - migration_bitmap_rcu->unsentmap = bitmap_new(ram_bitmap_pages);
> - bitmap_set(migration_bitmap_rcu->unsentmap, 0, ram_bitmap_pages);
> + rs->ram_bitmap->unsentmap = bitmap_new(ram_bitmap_pages);
> + bitmap_set(rs->ram_bitmap->unsentmap, 0, ram_bitmap_pages);
> }
> }
>
> --
> 2.9.3
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [PATCH 19/31] ram: move xbzrle_overflows into RAMState, (continued)
- [Qemu-devel] [PATCH 21/31] ram: Everything was init to zero, so use memset, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 18/31] ram: move xbzrle_cache_miss_rate into RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 17/31] ram: Move xbzrle_cache_miss into RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 16/31] ram: Move xbzrle_pages into RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 22/31] ram: move migration_bitmap_mutex into RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 20/31] ram: move migration_dirty_pages to RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 23/31] ram: Move migration_bitmap_rcu into RAMState, Juan Quintela, 2017/03/15
- Re: [Qemu-devel] [PATCH 23/31] ram: Move migration_bitmap_rcu into RAMState,
Dr. David Alan Gilbert <=
- [Qemu-devel] [PATCH 25/31] ram: Use the RAMState bytes_transferred parameter, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 26/31] ram: Remove ram_save_remaining, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 27/31] ram: Move last_req_rb to RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 24/31] ram: Move bytes_transferred into RAMState, Juan Quintela, 2017/03/15
- [Qemu-devel] [PATCH 29/31] ram: Remove dirty_bytes_rate, Juan Quintela, 2017/03/15