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[Qemu-devel] Re: [PATCH 09/10] kvm: port qemu-kvm's bitmap scanning
From: |
Yoshiaki Tamura |
Subject: |
[Qemu-devel] Re: [PATCH 09/10] kvm: port qemu-kvm's bitmap scanning |
Date: |
Tue, 27 Apr 2010 13:49:15 +0900 |
Hi,
This patch may conflict with the patch I posted on April 19.
http://www.mail-archive.com/address@hidden/msg29941.html
If Marcelo's is going to be merged, I need to rebase the above to it.
It would be helpful if you could tell me the plan.
Thanks,
Yoshi
2010/4/27 Marcelo Tosatti <address@hidden>:
> Which is significantly faster.
>
> Signed-off-by: Marcelo Tosatti <address@hidden>
> ---
> kvm-all.c | 53 +++++++++++++++++++++++++++++++++++++----------------
> 1 files changed, 37 insertions(+), 16 deletions(-)
>
> diff --git a/kvm-all.c b/kvm-all.c
> index eabb097..ef45418 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -26,6 +26,7 @@
> #include "hw/hw.h"
> #include "gdbstub.h"
> #include "kvm.h"
> +#include "bswap.h"
>
> /* KVM uses PAGE_SIZE in it's definition of COALESCED_MMIO_MAX */
> #define PAGE_SIZE TARGET_PAGE_SIZE
> @@ -282,11 +283,41 @@ static int kvm_set_migration_log(int enable)
> return 0;
> }
>
> -static int test_le_bit(unsigned long nr, unsigned char *addr)
> +/* get kvm's dirty pages bitmap and update qemu's */
> +static int kvm_get_dirty_pages_log_range(unsigned long start_addr,
> + unsigned long *bitmap,
> + unsigned long offset,
> + unsigned long mem_size)
> {
> - return (addr[nr >> 3] >> (nr & 7)) & 1;
> + unsigned int i, j;
> + unsigned long page_number, addr, addr1, c;
> + ram_addr_t ram_addr;
> + unsigned int len = ((mem_size / TARGET_PAGE_SIZE) + HOST_LONG_BITS - 1) /
> + HOST_LONG_BITS;
> +
> + /*
> + * bitmap-traveling is faster than memory-traveling (for addr...)
> + * especially when most of the memory is not dirty.
> + */
> + for (i = 0; i < len; i++) {
> + if (bitmap[i] != 0) {
> + c = leul_to_cpu(bitmap[i]);
> + do {
> + j = ffsl(c) - 1;
> + c &= ~(1ul << j);
> + page_number = i * HOST_LONG_BITS + j;
> + addr1 = page_number * TARGET_PAGE_SIZE;
> + addr = offset + addr1;
> + ram_addr = cpu_get_physical_page_desc(addr);
> + cpu_physical_memory_set_dirty(ram_addr);
> + } while (c != 0);
> + }
> + }
> + return 0;
> }
>
> +#define ALIGN(x, y) (((x)+(y)-1) & ~((y)-1))
> +
> /**
> * kvm_physical_sync_dirty_bitmap - Grab dirty bitmap from kernel space
> * This function updates qemu's dirty bitmap using
> cpu_physical_memory_set_dirty().
> @@ -300,8 +331,6 @@ static int
> kvm_physical_sync_dirty_bitmap(target_phys_addr_t start_addr,
> {
> KVMState *s = kvm_state;
> unsigned long size, allocated_size = 0;
> - target_phys_addr_t phys_addr;
> - ram_addr_t addr;
> KVMDirtyLog d;
> KVMSlot *mem;
> int ret = 0;
> @@ -313,7 +342,7 @@ static int
> kvm_physical_sync_dirty_bitmap(target_phys_addr_t start_addr,
> break;
> }
>
> - size = ((mem->memory_size >> TARGET_PAGE_BITS) + 7) / 8;
> + size = ALIGN(((mem->memory_size) >> TARGET_PAGE_BITS),
> HOST_LONG_BITS) / 8;
> if (!d.dirty_bitmap) {
> d.dirty_bitmap = qemu_malloc(size);
> } else if (size > allocated_size) {
> @@ -330,17 +359,9 @@ static int
> kvm_physical_sync_dirty_bitmap(target_phys_addr_t start_addr,
> break;
> }
>
> - for (phys_addr = mem->start_addr, addr = mem->phys_offset;
> - phys_addr < mem->start_addr + mem->memory_size;
> - phys_addr += TARGET_PAGE_SIZE, addr += TARGET_PAGE_SIZE) {
> - unsigned char *bitmap = (unsigned char *)d.dirty_bitmap;
> - unsigned nr = (phys_addr - mem->start_addr) >> TARGET_PAGE_BITS;
> -
> - if (test_le_bit(nr, bitmap)) {
> - cpu_physical_memory_set_dirty(addr);
> - }
> - }
> - start_addr = phys_addr;
> + kvm_get_dirty_pages_log_range(mem->start_addr, d.dirty_bitmap,
> + mem->start_addr, mem->memory_size);
> + start_addr = mem->start_addr + mem->memory_size;
> }
> qemu_free(d.dirty_bitmap);
>
> --
> 1.6.6.1
[Qemu-devel] [PATCH 03/10] kvm: handle internal error, Marcelo Tosatti, 2010/04/26
[Qemu-devel] [PATCH 05/10] kvm_init_vcpu requires global lock held, Marcelo Tosatti, 2010/04/26