diff mbox series

[v2,15/24] bsd-user: Use page_find_range_empty for mmap_find_vma_reserved

Message ID 20230707204054.8792-18-richard.henderson@linaro.org
State New
Headers show
Series linux-user: mmap range fixes | expand

Commit Message

Richard Henderson July 7, 2023, 8:40 p.m. UTC 
Use the interval tree to find empty space, rather than
probing each page in turn.

Cc: Warner Losh <imp@bsdimp.com>
Cc: Kyle Evans <kevans@freebsd.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 bsd-user/mmap.c | 48 +++++++-----------------------------------------
 1 file changed, 7 insertions(+), 41 deletions(-)

Comments

Warner Losh July 7, 2023, 10:09 p.m. UTC | #1 
On Fri, Jul 7, 2023 at 2:41 PM Richard Henderson <
richard.henderson@linaro.org> wrote:

> Use the interval tree to find empty space, rather than
> probing each page in turn.
>
> Cc: Warner Losh <imp@bsdimp.com>
> Cc: Kyle Evans <kevans@freebsd.org>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
>

Reviewed-bt: Warner Losh <imp@bsdimp.com>

I tested the prior version (with a different, but equivalent change) and it
seemed to work where
things had been broken previously.

Warner


> ---
>  bsd-user/mmap.c | 48 +++++++-----------------------------------------
>  1 file changed, 7 insertions(+), 41 deletions(-)
>
> diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
> index 07b5b8055e..aca8764356 100644
> --- a/bsd-user/mmap.c
> +++ b/bsd-user/mmap.c
> @@ -222,50 +222,16 @@ unsigned long last_brk;
>  static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size,
>                                          abi_ulong alignment)
>  {
> -    abi_ulong addr;
> -    abi_ulong end_addr;
> -    int prot;
> -    int looped = 0;
> +    abi_ulong ret;
>
> -    if (size > reserved_va) {
> -        return (abi_ulong)-1;
> +    ret = page_find_range_empty(start, reserved_va, size, alignment);
> +    if (ret == -1 && start > TARGET_PAGE_SIZE) {
> +        /* Restart at the beginning of the address space. */
> +        ret = page_find_range_empty(TARGET_PAGE_SIZE, start - 1,
> +                                    size, alignment);
>      }
>
> -    size = HOST_PAGE_ALIGN(size) + alignment;
> -    end_addr = start + size;
> -    if (end_addr > reserved_va) {
> -        end_addr = reserved_va + 1;
> -    }
> -    addr = end_addr - qemu_host_page_size;
> -
> -    while (1) {
> -        if (addr > end_addr) {
> -            if (looped) {
> -                return (abi_ulong)-1;
> -            }
> -            end_addr = reserved_va + 1;
> -            addr = end_addr - qemu_host_page_size;
> -            looped = 1;
> -            continue;
> -        }
> -        prot = page_get_flags(addr);
> -        if (prot) {
> -            end_addr = addr;
> -        }
> -        if (end_addr - addr >= size) {
> -            break;
> -        }
> -        addr -= qemu_host_page_size;
> -    }
> -
> -    if (start == mmap_next_start) {
> -        mmap_next_start = addr;
> -    }
> -    /* addr is sufficiently low to align it up */
> -    if (alignment != 0) {
> -        addr = (addr + alignment) & ~(alignment - 1);
> -    }
> -    return addr;
> +    return ret;
>  }
>
>  /*
> --
> 2.34.1
>
>
diff mbox series

Patch

diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index 07b5b8055e..aca8764356 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -222,50 +222,16 @@  unsigned long last_brk;
 static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size,
                                         abi_ulong alignment)
 {
-    abi_ulong addr;
-    abi_ulong end_addr;
-    int prot;
-    int looped = 0;
+    abi_ulong ret;
 
-    if (size > reserved_va) {
-        return (abi_ulong)-1;
+    ret = page_find_range_empty(start, reserved_va, size, alignment);
+    if (ret == -1 && start > TARGET_PAGE_SIZE) {
+        /* Restart at the beginning of the address space. */
+        ret = page_find_range_empty(TARGET_PAGE_SIZE, start - 1,
+                                    size, alignment);
     }
 
-    size = HOST_PAGE_ALIGN(size) + alignment;
-    end_addr = start + size;
-    if (end_addr > reserved_va) {
-        end_addr = reserved_va + 1;
-    }
-    addr = end_addr - qemu_host_page_size;
-
-    while (1) {
-        if (addr > end_addr) {
-            if (looped) {
-                return (abi_ulong)-1;
-            }
-            end_addr = reserved_va + 1;
-            addr = end_addr - qemu_host_page_size;
-            looped = 1;
-            continue;
-        }
-        prot = page_get_flags(addr);
-        if (prot) {
-            end_addr = addr;
-        }
-        if (end_addr - addr >= size) {
-            break;
-        }
-        addr -= qemu_host_page_size;
-    }
-
-    if (start == mmap_next_start) {
-        mmap_next_start = addr;
-    }
-    /* addr is sufficiently low to align it up */
-    if (alignment != 0) {
-        addr = (addr + alignment) & ~(alignment - 1);
-    }
-    return addr;
+    return ret;
 }
 
 /*