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[Qemu-devel] Re: [PATCH 1/3] qemu-kvm: Wrap phys_ram_dirty with addition
From: |
Avi Kivity |
Subject: |
[Qemu-devel] Re: [PATCH 1/3] qemu-kvm: Wrap phys_ram_dirty with additional inline functions. |
Date: |
Thu, 11 Feb 2010 14:42:33 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.7) Gecko/20100120 Fedora/3.0.1-1.fc12 Thunderbird/3.0.1 |
On 02/08/2010 12:22 PM, OHMURA Kei wrote:
> We think access phys_ram_dirty through inline functions is better
> than directly for encoupseling reason.
>
> We devided the ram in a 64 pages block. Each block has a counter, which is
> stored in phys_ram_dirty_by_word. It shows the number of dirty pages.
> We will find the 64 pages block is dirty or non-dirty using
> phys_ram_dirty_by_word.
>
> Signed-off-by: OHMURA Kei <address@hidden>
> ---
> cpu-all.h | 74
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> cpu-defs.h | 1 +
> 2 files changed, 75 insertions(+), 0 deletions(-)
>
> diff --git a/cpu-all.h b/cpu-all.h
> index 8ed76c7..2251f14 100644
> --- a/cpu-all.h
> +++ b/cpu-all.h
> @@ -168,6 +168,33 @@ typedef union {
> } CPU_QuadU;
> #endif
>
> +static inline unsigned long unroll_flags_to_ul(int flags)
> +{
> + unsigned long ret = 0, flags_ul = (unsigned long)flags;
> +
> +#if TARGET_LONG_SIZE == 4
> + ret |= flags_ul << 0;
> + ret |= flags_ul << 8;
> + ret |= flags_ul << 16;
> + ret |= flags_ul << 24;
> +#elif TARGET_LONG_SIZE == 8
> + ret |= flags_ul << 0;
> + ret |= flags_ul << 8;
> + ret |= flags_ul << 16;
> + ret |= flags_ul << 24;
> + ret |= flags_ul << 32;
> + ret |= flags_ul << 40;
> + ret |= flags_ul << 48;
> + ret |= flags_ul << 56;
>
HOST_LONG_SIZE, not TARGET_LONG_SIZE.
> @@ -890,9 +923,50 @@ static inline int
> cpu_physical_memory_get_dirty(ram_addr_t addr,
>
> static inline void cpu_physical_memory_set_dirty(ram_addr_t addr)
> {
> + if (phys_ram_dirty[addr >> TARGET_PAGE_BITS] != 0xff)
> + ++phys_ram_dirty_by_word[(addr >> TARGET_PAGE_BITS) /
> + TARGET_LONG_BITS];
> +
> phys_ram_dirty[addr >> TARGET_PAGE_BITS] = 0xff;
> }
>
Why do you need a counter? It may be sufficient to set a single bit.
This reduces the memory overhead and perhaps cache thrashing.
--
error compiling committee.c: too many arguments to function