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Blame SOURCES/kvm-memory-use-find_next_bit-to-find-dirty-bits.patch

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From 11ef790c7cca491bba62d8cb94018c1cf78e033c Mon Sep 17 00:00:00 2001
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From: Juan Quintela <quintela@redhat.com>
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Date: Tue, 14 Jan 2014 15:07:36 +0100
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Subject: [PATCH 25/40] memory: use find_next_bit() to find dirty bits
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RH-Author: Juan Quintela <quintela@redhat.com>
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Message-id: <1389712071-23303-26-git-send-email-quintela@redhat.com>
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Patchwork-id: 56680
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O-Subject: [RHEL7 qemu-kvm PATCH 25/40] memory: use find_next_bit() to find dirty bits
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Bugzilla: 997559
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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RH-Acked-by: Orit Wasserman <owasserm@redhat.com>
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RH-Acked-by: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>
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This operation is way faster than doing it bit by bit.
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Signed-off-by: Juan Quintela <quintela@redhat.com>
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Reviewed-by: Eric Blake <eblake@redhat.com>
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Reviewed-by: Orit Wasserman <owasserm@redhat.com>
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(cherry picked from commit 1bafff0c7cb99972fd243464632eca0780c6a8f1)
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Signed-off-by: Juan Quintela <quintela@trasno.org>
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---
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 include/exec/memory-internal.h | 16 ++++++----------
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 1 file changed, 6 insertions(+), 10 deletions(-)
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 include/exec/memory-internal.h |   16 ++++++----------
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 1 files changed, 6 insertions(+), 10 deletions(-)
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diff --git a/include/exec/memory-internal.h b/include/exec/memory-internal.h
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index caff5b4..1eda526 100644
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--- a/include/exec/memory-internal.h
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+++ b/include/exec/memory-internal.h
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@@ -53,19 +53,15 @@ static inline bool cpu_physical_memory_get_dirty(ram_addr_t start,
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                                                  ram_addr_t length,
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                                                  unsigned client)
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 {
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-    ram_addr_t addr, end;
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+    unsigned long end, page, next;
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     assert(client < DIRTY_MEMORY_NUM);
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-    end = TARGET_PAGE_ALIGN(start + length);
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-    start &= TARGET_PAGE_MASK;
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-    for (addr = start; addr < end; addr += TARGET_PAGE_SIZE) {
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-        if (test_bit(addr >> TARGET_PAGE_BITS,
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-                     ram_list.dirty_memory[client])) {
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-            return true;
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-        }
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-    }
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-    return false;
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+    end = TARGET_PAGE_ALIGN(start + length) >> TARGET_PAGE_BITS;
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+    page = start >> TARGET_PAGE_BITS;
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+    next = find_next_bit(ram_list.dirty_memory[client], end, page);
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+
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+    return next < end;
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 }
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 static inline bool cpu_physical_memory_get_dirty_flag(ram_addr_t addr,
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-- 
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1.7.1
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