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From: Peter Xu <peterx@redhat.com>
To: qemu-devel@nongnu.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Keqian Zhu <zhukeqian1@huawei.com>,
	Hyman <huangy81@chinatelecom.cn>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	peterx@redhat.com
Subject: [PATCH v6 01/10] memory: Introduce log_sync_global() to memory listener
Date: Wed, 24 Mar 2021 14:39:45 -0400	[thread overview]
Message-ID: <20210324183954.345629-2-peterx@redhat.com> (raw)
In-Reply-To: <20210324183954.345629-1-peterx@redhat.com>

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 ranges in the
address space.

Make this new method be exclusive to log_sync().

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/exec/memory.h | 12 ++++++++++++
 softmmu/memory.c      | 33 +++++++++++++++++++++++----------
 2 files changed, 35 insertions(+), 10 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 5728a681b27..97de5a8fa1e 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -616,6 +616,18 @@ 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/softmmu/memory.c b/softmmu/memory.c
index d4493ef9e43..ea36805e2e9 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -2057,6 +2057,10 @@ 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;
@@ -2070,18 +2074,24 @@ 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);
     }
 }
 
@@ -2769,6 +2779,9 @@ 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) {
-- 
2.26.2



  reply	other threads:[~2021-03-24 18:43 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-24 18:39 [PATCH v6 00/10] KVM: Dirty ring support (QEMU part) Peter Xu
2021-03-24 18:39 ` Peter Xu [this message]
2021-03-24 18:39 ` [PATCH v6 02/10] KVM: Use a big lock to replace per-kml slots_lock Peter Xu
2021-03-24 18:39 ` [PATCH v6 03/10] KVM: Create the KVMSlot dirty bitmap on flag changes Peter Xu
2021-03-24 18:39 ` [PATCH v6 04/10] KVM: Provide helper to get kvm dirty log Peter Xu
2021-03-24 18:39 ` [PATCH v6 05/10] KVM: Provide helper to sync dirty bitmap from slot to ramblock Peter Xu
2021-03-24 18:39 ` [PATCH v6 06/10] KVM: Simplify dirty log sync in kvm_set_phys_mem Peter Xu
2021-03-24 18:39 ` [PATCH v6 07/10] KVM: Cache kvm slot dirty bitmap size Peter Xu
2021-03-24 18:39 ` [PATCH v6 08/10] KVM: Add dirty-gfn-count property Peter Xu
2021-03-24 18:39 ` [PATCH v6 09/10] KVM: Disable manual dirty log when dirty ring enabled Peter Xu
2021-03-24 18:41 ` [PATCH v6 10/10] KVM: Dirty ring support Peter Xu
2021-04-29 21:07 ` [PATCH v6 00/10] KVM: Dirty ring support (QEMU part) Peter Xu

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