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linux-user: Use page_find_range_empty for mmap_find_vma_reserved 

Use the interval tree to find empty space, rather than
probing each page in turn.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230707204054.8792-19-richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2023-07-07 21:40:46 +01:00
parent f12294b5bd
commit 4c13048e02
1 changed files with 6 additions and 46 deletions
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52
linux-user/mmap.c
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@ -318,55 +318,15 @@ unsigned long last_brk;
static abi_ulong mmap_find_vma_reserved(abi_ulong start, abi_ulong size,
abi_ulong align)
{
abi_ulong addr, end_addr, incr = qemu_host_page_size;
int prot;
bool looped = false;
target_ulong ret;
if (size > reserved_va) {
return (abi_ulong)-1;
ret = page_find_range_empty(start, reserved_va, size, align);
if (ret == -1 && start > mmap_min_addr) {
/* Restart at the beginning of the address space. */
ret = page_find_range_empty(mmap_min_addr, start - 1, size, align);
}
/* Note that start and size have already been aligned by mmap_find_vma. */
end_addr = start + size;
/*
* Start at the top of the address space, ignoring the last page.
* If reserved_va == UINT32_MAX, then end_addr wraps to 0,
* throwing the rest of the calculations off.
* TODO: rewrite using last_addr instead.
* TODO: use the interval tree instead of probing every page.
*/
if (start > reserved_va - size) {
end_addr = ((reserved_va - size) & -align) + size;
looped = true;
}
/* Search downward from END_ADDR, checking to see if a page is in use. */
addr = end_addr;
while (1) {
addr -= incr;
if (addr > end_addr) {
if (looped) {
/* Failure. The entire address space has been searched. */
return (abi_ulong)-1;
}
/* Re-start at the top of the address space (see above). */
addr = end_addr = ((reserved_va - size) & -align) + size;
looped = true;
} else {
prot = page_get_flags(addr);
if (prot) {
/* Page in use. Restart below this page. */
addr = end_addr = ((addr - size) & -align) + size;
} else if (addr && addr + size == end_addr) {
/* Success! All pages between ADDR and END_ADDR are free. */
if (start == mmap_next_start) {
mmap_next_start = addr;
}
return addr;
}
}
}
return ret;
}
/*