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[Qemu-devel] [PATCH 1/3] migration/postcopy: not necessary to do discard
From: |
Wei Yang |
Subject: |
[Qemu-devel] [PATCH 1/3] migration/postcopy: not necessary to do discard when canonicalizing bitmap |
Date: |
Mon, 19 Aug 2019 14:18:41 +0800 |
All pages, either partially sent or partially dirty, will be discarded in
postcopy_send_discard_bm_ram(), since we update the unsentmap to be
unsentmap = unsentmap | dirty in ram_postcopy_send_discard_bitmap().
This is not necessary to do discard when canonicalizing bitmap. And by
doing so, we separate the page discard into two individual steps:
* canonicalize bitmap
* discard page
Signed-off-by: Wei Yang <address@hidden>
---
migration/ram.c | 14 +-------------
1 file changed, 1 insertion(+), 13 deletions(-)
diff --git a/migration/ram.c b/migration/ram.c
index 35552c090b..075ddc468c 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2928,7 +2928,7 @@ static int postcopy_each_ram_send_discard(MigrationState
*ms)
}
/**
- * postcopy_chunk_hostpages_pass: canocalize bitmap in hostpages
+ * postcopy_chunk_hostpages_pass: canonicalize bitmap in hostpages
*
* Helper for postcopy_chunk_hostpages; it's called twice to
* canonicalize the two bitmaps, that are similar, but one is
@@ -2991,18 +2991,6 @@ static void postcopy_chunk_hostpages_pass(MigrationState
*ms, bool unsent_pass,
host_ratio);
run_start = QEMU_ALIGN_UP(run_start, host_ratio);
- /* Tell the destination to discard this page */
- if (unsent_pass || !test_bit(fixup_start_addr, unsentmap)) {
- /* For the unsent_pass we:
- * discard partially sent pages
- * For the !unsent_pass (dirty) we:
- * discard partially dirty pages that were sent
- * (any partially sent pages were already discarded
- * by the previous unsent_pass)
- */
- postcopy_discard_send_range(ms, fixup_start_addr, host_ratio);
- }
-
/* Clean up the bitmap */
for (page = fixup_start_addr;
page < fixup_start_addr + host_ratio; page++) {
--
2.17.1