From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Peter Xu <peterx@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
qemu-devel@nongnu.org, "Michael S . Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH RFC 3/9] memory: Introduce log_sync_global() to memory listener
Date: Wed, 25 Mar 2020 16:52:52 +0000 [thread overview]
Message-ID: <20200325165252.GB2635@work-vm> (raw)
In-Reply-To: <20200205141749.378044-4-peterx@redhat.com>
* Peter Xu (peterx@redhat.com) wrote:
> Some of the memory listener may want to do log synchronization without
> being able to specify a range of memory to sync but always globally.
> Such a memory listener should provide this new method instead of the
> log_sync() method.
>
> Obviously we can also achieve similar thing when we put the global
> sync logic into a log_sync() handler. However that's not efficient
> enough because otherwise memory_global_dirty_log_sync() may do the
> global sync N times, where N is the number of flat views.
>
> Make this new method be exclusive to log_sync().
>
> Signed-off-by: Peter Xu <peterx@redhat.com>
OK, so I guess the idea here is that when you have a ring with dirty
pages on it, you just need to clear all outstanding things on the ring
whereever they came from.
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
> include/exec/memory.h | 12 ++++++++++++
> memory.c | 33 +++++++++++++++++++++++----------
> 2 files changed, 35 insertions(+), 10 deletions(-)
>
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index e85b7de99a..c4427094bb 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -533,6 +533,18 @@ struct MemoryListener {
> */
> void (*log_sync)(MemoryListener *listener, MemoryRegionSection *section);
>
> + /**
> + * @log_sync_global:
> + *
> + * This is the global version of @log_sync when the listener does
> + * not have a way to synchronize the log with finer granularity.
> + * When the listener registers with @log_sync_global defined, then
> + * its @log_sync must be NULL. Vice versa.
> + *
> + * @listener: The #MemoryListener.
> + */
> + void (*log_sync_global)(MemoryListener *listener);
> +
> /**
> * @log_clear:
> *
> diff --git a/memory.c b/memory.c
> index aeaa8dcc9e..53828ba00c 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -2016,6 +2016,10 @@ void memory_region_set_dirty(MemoryRegion *mr, hwaddr addr,
> memory_region_get_dirty_log_mask(mr));
> }
>
> +/*
> + * If memory region `mr' is NULL, do global sync. Otherwise, sync
> + * dirty bitmap for the specified memory region.
> + */
> static void memory_region_sync_dirty_bitmap(MemoryRegion *mr)
> {
> MemoryListener *listener;
> @@ -2029,18 +2033,24 @@ static void memory_region_sync_dirty_bitmap(MemoryRegion *mr)
> * address space once.
> */
> QTAILQ_FOREACH(listener, &memory_listeners, link) {
> - if (!listener->log_sync) {
> - continue;
> - }
> - as = listener->address_space;
> - view = address_space_get_flatview(as);
> - FOR_EACH_FLAT_RANGE(fr, view) {
> - if (fr->dirty_log_mask && (!mr || fr->mr == mr)) {
> - MemoryRegionSection mrs = section_from_flat_range(fr, view);
> - listener->log_sync(listener, &mrs);
> + if (listener->log_sync) {
> + as = listener->address_space;
> + view = address_space_get_flatview(as);
> + FOR_EACH_FLAT_RANGE(fr, view) {
> + if (fr->dirty_log_mask && (!mr || fr->mr == mr)) {
> + MemoryRegionSection mrs = section_from_flat_range(fr, view);
> + listener->log_sync(listener, &mrs);
> + }
> }
> + flatview_unref(view);
> + } else if (listener->log_sync_global) {
> + /*
> + * No matter whether MR is specified, what we can do here
> + * is to do a global sync, because we are not capable to
> + * sync in a finer granularity.
> + */
> + listener->log_sync_global(listener);
> }
> - flatview_unref(view);
> }
> }
>
> @@ -2727,6 +2737,9 @@ void memory_listener_register(MemoryListener *listener, AddressSpace *as)
> {
> MemoryListener *other = NULL;
>
> + /* Only one of them can be defined for a listener */
> + assert(!(listener->log_sync && listener->log_sync_global));
> +
> listener->address_space = as;
> if (QTAILQ_EMPTY(&memory_listeners)
> || listener->priority >= QTAILQ_LAST(&memory_listeners)->priority) {
> --
> 2.24.1
>
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
next prev parent reply other threads:[~2020-03-25 16:53 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-05 14:17 [PATCH RFC 0/9] KVM: Dirty ring support (QEMU part) Peter Xu
2020-02-05 14:17 ` [PATCH RFC 1/9] KVM: Fixup kvm_log_clear_one_slot() ioctl return check Peter Xu
2020-03-25 16:34 ` Dr. David Alan Gilbert
2020-03-25 17:43 ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 2/9] linux-headers: Update Peter Xu
2020-02-05 14:17 ` [PATCH RFC 3/9] memory: Introduce log_sync_global() to memory listener Peter Xu
2020-03-25 16:52 ` Dr. David Alan Gilbert [this message]
2020-03-25 17:02 ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 4/9] KVM: Create the KVMSlot dirty bitmap on flag changes Peter Xu
2020-03-25 17:44 ` Dr. David Alan Gilbert
2020-02-05 14:17 ` [PATCH RFC 5/9] KVM: Provide helper to get kvm dirty log Peter Xu
2020-03-25 17:52 ` Dr. David Alan Gilbert
2020-03-25 18:15 ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 6/9] KVM: Provide helper to sync dirty bitmap from slot to ramblock Peter Xu
2020-03-25 18:47 ` Dr. David Alan Gilbert
2020-02-05 14:17 ` [PATCH RFC 7/9] KVM: Cache kvm slot dirty bitmap size Peter Xu
2020-03-25 18:49 ` Dr. David Alan Gilbert
2020-02-05 14:17 ` [PATCH RFC 8/9] KVM: Add dirty-ring-size property Peter Xu
2020-03-25 20:00 ` Dr. David Alan Gilbert
2020-03-25 20:42 ` Peter Xu
2020-03-26 13:41 ` Dr. David Alan Gilbert
2020-03-26 16:03 ` Peter Xu
2020-03-25 20:14 ` Dr. David Alan Gilbert
2020-03-25 20:48 ` Peter Xu
2020-02-05 14:17 ` [PATCH RFC 9/9] KVM: Dirty ring support Peter Xu
2020-03-25 20:41 ` Dr. David Alan Gilbert
2020-03-25 21:32 ` Peter Xu
2020-03-26 14:14 ` Dr. David Alan Gilbert
2020-03-26 16:10 ` Peter Xu
2020-02-05 14:51 ` [PATCH RFC 0/9] KVM: Dirty ring support (QEMU part) no-reply
2020-03-03 17:32 ` Peter Xu
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