dbb644f20c
It's now possible to get purgeable memory by using mmap(MAP_PURGEABLE). Purgeable memory has a "volatile" flag that can be set using madvise(): - madvise(..., MADV_SET_VOLATILE) - madvise(..., MADV_SET_NONVOLATILE) When in the "volatile" state, the kernel may take away the underlying physical memory pages at any time, without notifying the owner. This gives you a guilt discount when caching very large things. :^) Setting a purgeable region to non-volatile will return whether or not the memory has been taken away by the kernel while being volatile. Basically, if madvise(..., MADV_SET_NONVOLATILE) returns 1, that means the memory was purged while volatile, and whatever was in that piece of memory needs to be reconstructed before use.
66 lines
1.6 KiB
C++
66 lines
1.6 KiB
C++
#include <Kernel/Syscall.h>
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#include <errno.h>
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#include <mman.h>
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#include <stdio.h>
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extern "C" {
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void* mmap(void* addr, size_t size, int prot, int flags, int fd, off_t offset)
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{
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Syscall::SC_mmap_params params { (u32)addr, size, prot, flags, fd, offset, nullptr };
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int rc = syscall(SC_mmap, ¶ms);
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if (rc < 0 && -rc < EMAXERRNO) {
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errno = -rc;
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return (void*)-1;
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}
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return (void*)rc;
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}
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void* mmap_with_name(void* addr, size_t size, int prot, int flags, int fd, off_t offset, const char* name)
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{
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Syscall::SC_mmap_params params { (u32)addr, size, prot, flags, fd, offset, name };
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int rc = syscall(SC_mmap, ¶ms);
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if (rc < 0 && -rc < EMAXERRNO) {
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errno = -rc;
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return (void*)-1;
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}
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return (void*)rc;
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}
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int munmap(void* addr, size_t size)
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{
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int rc = syscall(SC_munmap, addr, size);
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__RETURN_WITH_ERRNO(rc, rc, -1);
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}
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int mprotect(void* addr, size_t size, int prot)
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{
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int rc = syscall(SC_mprotect, addr, size, prot);
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__RETURN_WITH_ERRNO(rc, rc, -1);
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}
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int set_mmap_name(void* addr, size_t size, const char* name)
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{
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int rc = syscall(SC_set_mmap_name, addr, size, name);
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__RETURN_WITH_ERRNO(rc, rc, -1);
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}
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int shm_open(const char* name, int flags, mode_t mode)
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{
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int rc = syscall(SC_shm_open, name, flags, mode);
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__RETURN_WITH_ERRNO(rc, rc, -1);
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}
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int shm_unlink(const char* name)
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{
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int rc = syscall(SC_shm_unlink, name);
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__RETURN_WITH_ERRNO(rc, rc, -1);
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}
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int madvise(void* address, size_t size, int advice)
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{
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int rc = syscall(SC_madvise, address, size, advice);
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__RETURN_WITH_ERRNO(rc, rc, -1);
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}
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}
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