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Re: [Qemu-devel] [PATCH v3 3/3] memory: drop some wrappers that waste cp
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH v3 3/3] memory: drop some wrappers that waste cpu cycle |
Date: |
Tue, 17 May 2016 09:50:44 +0800 |
User-agent: |
Mutt/1.6.1 (2016-04-27) |
On Thu, 05/12 18:07, Gonglei wrote:
> For better performance, we can use RAMblock
> directly stored in memory_region at present.
>
> Signed-off-by: Gonglei <address@hidden>
> ---
> exec.c | 33 ++-------------------------------
> hw/misc/ivshmem.c | 8 +++++---
> hw/virtio/vhost-user.c | 13 ++++++++-----
> include/exec/ram_addr.h | 4 +---
> memory.c | 2 +-
> 5 files changed, 17 insertions(+), 43 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index 117c9a8..f8de928 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -1812,38 +1812,9 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length)
> }
> #endif /* !_WIN32 */
>
> -int qemu_get_ram_fd(ram_addr_t addr)
> +void *qemu_get_ram_block_host_ptr(RAMBlock *ram_block)
> {
> - RAMBlock *block;
> - int fd;
> -
> - rcu_read_lock();
> - block = qemu_get_ram_block(addr);
> - fd = block->fd;
> - rcu_read_unlock();
> - return fd;
> -}
> -
> -void qemu_set_ram_fd(ram_addr_t addr, int fd)
> -{
> - RAMBlock *block;
> -
> - rcu_read_lock();
> - block = qemu_get_ram_block(addr);
> - block->fd = fd;
> - rcu_read_unlock();
> -}
> -
> -void *qemu_get_ram_block_host_ptr(ram_addr_t addr)
> -{
> - RAMBlock *block;
> - void *ptr;
> -
> - rcu_read_lock();
> - block = qemu_get_ram_block(addr);
> - ptr = ramblock_ptr(block, 0);
> - rcu_read_unlock();
> - return ptr;
> + return ramblock_ptr(ram_block, 0);
> }
>
> /* Return a host pointer to ram allocated with qemu_ram_alloc.
> diff --git a/hw/misc/ivshmem.c b/hw/misc/ivshmem.c
> index e40f23b..1e930fa 100644
> --- a/hw/misc/ivshmem.c
> +++ b/hw/misc/ivshmem.c
> @@ -533,7 +533,9 @@ static void process_msg_shmem(IVShmemState *s, int fd,
> Error **errp)
> }
> memory_region_init_ram_ptr(&s->server_bar2, OBJECT(s),
> "ivshmem.bar2", size, ptr);
> - qemu_set_ram_fd(memory_region_get_ram_addr(&s->server_bar2), fd);
> + assert(s->server_bar2.ram_block);
> + s->server_bar2.ram_block->fd = fd;
> +
> s->ivshmem_bar2 = &s->server_bar2;
> }
>
> @@ -939,8 +941,8 @@ static void ivshmem_exit(PCIDevice *dev)
> error_report("Failed to munmap shared memory %s",
> strerror(errno));
> }
> -
> - fd =
> qemu_get_ram_fd(memory_region_get_ram_addr(s->ivshmem_bar2));
Maybe this is okay but personally I think it is cleaner to add a
qemu_{set,get}_ramblock_fd pair.
Fam