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[Qemu-devel] [PATCH v5 3/5] migration: API to clear bits of guest free p
From: |
Wei Wang |
Subject: |
[Qemu-devel] [PATCH v5 3/5] migration: API to clear bits of guest free pages from the dirty bitmap |
Date: |
Fri, 16 Mar 2018 18:48:27 +0800 |
This patch adds an API to clear bits corresponding to guest free pages
from the dirty bitmap. Spilt the free page block if it crosses the QEMU
RAMBlock boundary.
Signed-off-by: Wei Wang <address@hidden>
CC: Dr. David Alan Gilbert <address@hidden>
CC: Juan Quintela <address@hidden>
CC: Michael S. Tsirkin <address@hidden>
---
include/migration/misc.h | 2 ++
migration/ram.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+)
diff --git a/include/migration/misc.h b/include/migration/misc.h
index 77fd4f5..fae1acf 100644
--- a/include/migration/misc.h
+++ b/include/migration/misc.h
@@ -14,11 +14,13 @@
#ifndef MIGRATION_MISC_H
#define MIGRATION_MISC_H
+#include "exec/cpu-common.h"
#include "qemu/notify.h"
/* migration/ram.c */
void ram_mig_init(void);
+void qemu_guest_free_page_hint(void *addr, size_t len);
/* migration/block.c */
diff --git a/migration/ram.c b/migration/ram.c
index 38c991d..2e82181 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2193,6 +2193,50 @@ static int ram_init_all(RAMState **rsp)
}
/*
+ * This function clears bits of the free pages reported by the caller from the
+ * migration dirty bitmap. @addr is the host address corresponding to the
+ * start of the continuous guest free pages, and @len is the total bytes of
+ * those pages.
+ */
+void qemu_guest_free_page_hint(void *addr, size_t len)
+{
+ RAMBlock *block;
+ ram_addr_t offset;
+ size_t used_len, start, npages;
+
+ for (; len > 0; len -= used_len) {
+ block = qemu_ram_block_from_host(addr, false, &offset);
+ if (unlikely(!block)) {
+ return;
+ }
+
+ /*
+ * This handles the case that the RAMBlock is resized after the free
+ * page hint is reported.
+ */
+ if (unlikely(offset > block->used_length)) {
+ return;
+ }
+
+ if (len <= block->used_length - offset) {
+ used_len = len;
+ } else {
+ used_len = block->used_length - offset;
+ addr += used_len;
+ }
+
+ start = offset >> TARGET_PAGE_BITS;
+ npages = used_len >> TARGET_PAGE_BITS;
+
+ qemu_mutex_lock(&ram_state->bitmap_mutex);
+ ram_state->migration_dirty_pages -=
+ bitmap_count_one_with_offset(block->bmap, start, npages);
+ bitmap_clear(block->bmap, start, npages);
+ qemu_mutex_unlock(&ram_state->bitmap_mutex);
+ }
+}
+
+/*
* Each of ram_save_setup, ram_save_iterate and ram_save_complete has
* long-running RCU critical section. When rcu-reclaims in the code
* start to become numerous it will be necessary to reduce the
--
1.8.3.1
- [Qemu-devel] [PATCH v5 0/5] virtio-balloon: free page hint reporting support, Wei Wang, 2018/03/16
- [Qemu-devel] [PATCH v5 1/5] bitmap: bitmap_count_one_with_offset, Wei Wang, 2018/03/16
- [Qemu-devel] [PATCH v5 5/5] migration: use the free page hint feature from balloon, Wei Wang, 2018/03/16
- [Qemu-devel] [PATCH v5 2/5] migration: use bitmap_mutex in migration_bitmap_clear_dirty, Wei Wang, 2018/03/16
- [Qemu-devel] [PATCH v5 3/5] migration: API to clear bits of guest free pages from the dirty bitmap,
Wei Wang <=
- [Qemu-devel] [PATCH v5 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Wei Wang, 2018/03/16
- Re: [Qemu-devel] [PATCH v5 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Michael S. Tsirkin, 2018/03/16
- Re: [Qemu-devel] [PATCH v5 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Wei Wang, 2018/03/18
- Re: [Qemu-devel] [PATCH v5 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Michael S. Tsirkin, 2018/03/19
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v5 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Wei Wang, 2018/03/19
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v5 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Michael S. Tsirkin, 2018/03/19
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v5 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Wei Wang, 2018/03/19
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v5 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Michael S. Tsirkin, 2018/03/19
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v5 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Wei Wang, 2018/03/19
- Re: [Qemu-devel] [virtio-dev] Re: [PATCH v5 4/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT, Michael S. Tsirkin, 2018/03/19