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Re: [PATCH v4 2/6] memory: make global_dirty_log a bitmask
From: |
Peter Xu |
Subject: |
Re: [PATCH v4 2/6] memory: make global_dirty_log a bitmask |
Date: |
Wed, 16 Jun 2021 11:22:43 -0400 |
On Wed, Jun 16, 2021 at 09:12:28AM +0800, huangy81@chinatelecom.cn wrote:
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index b114f54..e31eef2 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -55,7 +55,11 @@ static inline void fuzz_dma_read_cb(size_t addr,
> }
> #endif
>
> -extern bool global_dirty_log;
> +/* what is the purpose of current dirty log, migration or dirty rate ? */
Nitpick: I'll make it:
/* Possible bits for global_dirty_log */
/* Dirty tracking enabled because migration is running */
#define GLOBAL_DIRTY_MIGRATION (1U << 0)
/* Dirty tracking enabled because measuring dirty rate */
#define GLOBAL_DIRTY_DIRTY_RATE (1U << 1)
> +#define GLOBAL_DIRTY_MIGRATION (1U << 0)
> +#define GLOBAL_DIRTY_DIRTY_RATE (1U << 1)
> +
> +extern unsigned int global_dirty_log;
>
> typedef struct MemoryRegionOps MemoryRegionOps;
>
[...]
> @@ -39,7 +39,7 @@
> static unsigned memory_region_transaction_depth;
> static bool memory_region_update_pending;
> static bool ioeventfd_update_pending;
> -bool global_dirty_log;
> +unsigned int global_dirty_log;
I'm wondering whether it's a good chance to rename it to global_dirty_tracking,
because "logging" has a hint on the method while it's not the only one now.
>
> static QTAILQ_HEAD(, MemoryListener) memory_listeners
> = QTAILQ_HEAD_INITIALIZER(memory_listeners);
> @@ -2659,14 +2659,19 @@ void memory_global_after_dirty_log_sync(void)
>
> static VMChangeStateEntry *vmstate_change;
>
> -void memory_global_dirty_log_start(void)
> +void memory_global_dirty_log_start(unsigned int flags)
> {
> if (vmstate_change) {
> qemu_del_vm_change_state_handler(vmstate_change);
> vmstate_change = NULL;
> }
>
> - global_dirty_log = true;
> +#define GLOBAL_DIRTY_MASK (0x3)
> + assert(flags && !(flags & (~GLOBAL_DIRTY_MASK)));
> + assert(global_dirty_log ^ flags);
Heh, this is probably my fault... I think what I wanted to suggest is actually:
assert(!(global_dirty_log & flags));
Then for stop() below...
> + global_dirty_log |= flags;
> +
> + trace_global_dirty_changed(global_dirty_log);
>
> MEMORY_LISTENER_CALL_GLOBAL(log_global_start, Forward);
>
> @@ -2676,9 +2681,12 @@ void memory_global_dirty_log_start(void)
> memory_region_transaction_commit();
> }
>
> -static void memory_global_dirty_log_do_stop(void)
> +static void memory_global_dirty_log_do_stop(unsigned int flags)
> {
> - global_dirty_log = false;
> + assert(flags && !(flags & (~GLOBAL_DIRTY_MASK)));
... it should probably be:
assert((global_dirty_log & flags) == flags);
Sorry about the confusion.
--
Peter Xu
- [PATCH v4 0/6] support dirtyrate at the granualrity of vcpu, huangy81, 2021/06/15
- [PATCH v4 1/6] KVM: introduce dirty_pages and kvm_dirty_ring_enabled, huangy81, 2021/06/15
- [PATCH v4 2/6] memory: make global_dirty_log a bitmask, huangy81, 2021/06/15
- Re: [PATCH v4 2/6] memory: make global_dirty_log a bitmask,
Peter Xu <=
- [PATCH v4 4/6] migration/dirtyrate: adjust order of registering thread, huangy81, 2021/06/15
- [PATCH v4 3/6] migration/dirtyrate: introduce struct and adjust DirtyRateStat, huangy81, 2021/06/15
- [PATCH v4 5/6] migration/dirtyrate: move init step of calculation to main thread, huangy81, 2021/06/15
- [PATCH v4 6/6] migration/dirtyrate: implement dirty-ring dirtyrate calculation, huangy81, 2021/06/15