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Re: [Qemu-devel] [PATCH 37/51] ram: Move compression_switch to RAMState
From: |
Juan Quintela |
Subject: |
Re: [Qemu-devel] [PATCH 37/51] ram: Move compression_switch to RAMState |
Date: |
Thu, 30 Mar 2017 18:27:32 +0200 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) |
"Dr. David Alan Gilbert" <address@hidden> wrote:
> * Juan Quintela (address@hidden) wrote:
>> Rename it to preffer_xbzrle that is a more descriptive name.
>>
>> Signed-off-by: Juan Quintela <address@hidden>
>> ---
>> migration/ram.c | 9 +++++----
>> 1 file changed, 5 insertions(+), 4 deletions(-)
>>
>> diff --git a/migration/ram.c b/migration/ram.c
>> index 6a39704..591cf89 100644
>> --- a/migration/ram.c
>> +++ b/migration/ram.c
>> @@ -217,6 +217,9 @@ struct RAMState {
>> uint64_t dirty_pages_rate;
>> /* Count of requests incoming from destination */
>> uint64_t postcopy_requests;
>> + /* Should we move to xbzrle after the 1st round
>> + of compression */
>> + bool preffer_xbzrle;
>
> That's 'prefer' - however, do we need it at all?
> How about just replacing it by:
> !ram_bulk_stage && migrate_use_xbzrle()
>
> would that work?
if (migrate_use_compression()) &&
(rs->ram_bulk_stage || !migrate_use_xbzrle()) {
res = ram_save_compressed_page(rs, ms, pss, last_stage);
To remove the two !(!...) I changed to this.
Later, Juan.
>
> Dave
>
>> /* protects modification of the bitmap */
>> QemuMutex bitmap_mutex;
>> /* Ram Bitmap protected by RCU */
>> @@ -335,7 +338,6 @@ static QemuCond comp_done_cond;
>> /* The empty QEMUFileOps will be used by file in CompressParam */
>> static const QEMUFileOps empty_ops = { };
>>
>> -static bool compression_switch;
>> static DecompressParam *decomp_param;
>> static QemuThread *decompress_threads;
>> static QemuMutex decomp_done_lock;
>> @@ -419,7 +421,6 @@ void migrate_compress_threads_create(void)
>> if (!migrate_use_compression()) {
>> return;
>> }
>> - compression_switch = true;
>> thread_count = migrate_compress_threads();
>> compress_threads = g_new0(QemuThread, thread_count);
>> comp_param = g_new0(CompressParam, thread_count);
>> @@ -1091,7 +1092,7 @@ static bool find_dirty_block(RAMState *rs,
>> PageSearchStatus *pss,
>> * point. In theory, xbzrle can do better than compression.
>> */
>> flush_compressed_data(rs);
>> - compression_switch = false;
>> + rs->preffer_xbzrle = true;
>> }
>> }
>> /* Didn't find anything this time, but try again on the new block */
>> @@ -1323,7 +1324,7 @@ static int ram_save_target_page(RAMState *rs,
>> MigrationState *ms,
>> /* Check the pages is dirty and if it is send it */
>> if (migration_bitmap_clear_dirty(rs, dirty_ram_abs)) {
>> unsigned long *unsentmap;
>> - if (compression_switch && migrate_use_compression()) {
>> + if (!rs->preffer_xbzrle && migrate_use_compression()) {
>> res = ram_save_compressed_page(rs, ms, pss, last_stage);
>> } else {
>> res = ram_save_page(rs, ms, pss, last_stage);
>> --
>> 2.9.3
>>
> --
> Dr. David Alan Gilbert / address@hidden / Manchester, UK