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Always allocate linear memory using mmap (#3052)

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With this approach we can omit using memset() for the newly allocated memory
therefore the physical pages are not being used unless touched by the program.

This also simplifies the implementation.
This commit is contained in:
Marcin Kolny
2024-02-02 14:17:44 +00:00
committed by GitHub
parent 2eb60060d8
commit a27ddece7f
25 changed files with 384 additions and 425 deletions
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64
core/iwasm/common/wasm_runtime_common.c
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@ -6269,67 +6269,3 @@ wasm_runtime_set_linux_perf(bool flag)
enable_linux_perf = flag;
}
#endif
#ifdef WASM_LINEAR_MEMORY_MMAP
void
wasm_munmap_linear_memory(void *mapped_mem, uint64 commit_size, uint64 map_size)
{
#ifdef BH_PLATFORM_WINDOWS
os_mem_decommit(mapped_mem, commit_size);
#else
(void)commit_size;
#endif
os_munmap(mapped_mem, map_size);
}
void *
wasm_mmap_linear_memory(uint64_t map_size, uint64 *io_memory_data_size,
char *error_buf, uint32 error_buf_size)
{
uint64 page_size = os_getpagesize();
void *mapped_mem = NULL;
uint64 memory_data_size;
bh_assert(io_memory_data_size);
memory_data_size =
(*io_memory_data_size + page_size - 1) & ~(page_size - 1);
if (memory_data_size > UINT32_MAX)
memory_data_size = UINT32_MAX;
if (!(mapped_mem = os_mmap(NULL, map_size, MMAP_PROT_NONE, MMAP_MAP_NONE,
os_get_invalid_handle()))) {
set_error_buf(error_buf, error_buf_size, "mmap memory failed");
goto fail1;
}
#ifdef BH_PLATFORM_WINDOWS
if (memory_data_size > 0
&& !os_mem_commit(mapped_mem, memory_data_size,
MMAP_PROT_READ | MMAP_PROT_WRITE)) {
set_error_buf(error_buf, error_buf_size, "commit memory failed");
os_munmap(mapped_mem, map_size);
goto fail1;
}
#endif
if (os_mprotect(mapped_mem, memory_data_size,
MMAP_PROT_READ | MMAP_PROT_WRITE)
!= 0) {
set_error_buf(error_buf, error_buf_size, "mprotect memory failed");
goto fail2;
}
/* Newly allocated pages are filled with zero by the OS, we don't fill it
* again here */
*io_memory_data_size = memory_data_size;
return mapped_mem;
fail2:
wasm_munmap_linear_memory(mapped_mem, memory_data_size, map_size);
fail1:
return NULL;
}
#endif