motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-12-17 21:26:13 -07:00
Code Issues Projects Releases Packages Wiki Activity Actions

qemu: mempath: prefault pages manually (v4)

Browse source 
v4: s/fail/failed/  (Peter Maydell)

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This commit is contained in:
Marcelo Tosatti 2013-10-28 18:51:46 -02:00 • committed by Paolo Bonzini
parent fb541ca59c
commit ef36fa1492
3 changed files with 47 additions and 18 deletions
Download patch file Download diff file Expand all files Collapse all files

59
exec.c
View file

@ -904,6 +904,13 @@ static long gethugepagesize(const char *path)
return fs.f_bsize;
}
static sigjmp_buf sigjump;
static void sigbus_handler(int signal)
{
siglongjmp(sigjump, 1);
}
static void *file_ram_alloc(RAMBlock *block,
ram_addr_t memory,
const char *path)
@ -913,9 +920,6 @@ static void *file_ram_alloc(RAMBlock *block,
char *c;
void *area;
int fd;
#ifdef MAP_POPULATE
int flags;
#endif
unsigned long hpagesize;
hpagesize = gethugepagesize(path);
@ -963,21 +967,52 @@ static void *file_ram_alloc(RAMBlock *block,
if (ftruncate(fd, memory))
perror("ftruncate");
#ifdef MAP_POPULATE
/* NB: MAP_POPULATE won't exhaustively alloc all phys pages in the case
* MAP_PRIVATE is requested. For mem_prealloc we mmap as MAP_SHARED
* to sidestep this quirk.
*/
flags = mem_prealloc ? MAP_POPULATE | MAP_SHARED : MAP_PRIVATE;
area = mmap(0, memory, PROT_READ | PROT_WRITE, flags, fd, 0);
#else
area = mmap(0, memory, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
#endif
if (area == MAP_FAILED) {
perror("file_ram_alloc: can't mmap RAM pages");
close(fd);
return (NULL);
}
if (mem_prealloc) {
int ret, i;
struct sigaction act, oldact;
sigset_t set, oldset;
memset(&act, 0, sizeof(act));
act.sa_handler = &sigbus_handler;
act.sa_flags = 0;
ret = sigaction(SIGBUS, &act, &oldact);
if (ret) {
perror("file_ram_alloc: failed to install signal handler");
exit(1);
}
/* unblock SIGBUS */
sigemptyset(&set);
sigaddset(&set, SIGBUS);
pthread_sigmask(SIG_UNBLOCK, &set, &oldset);
if (sigsetjmp(sigjump, 1)) {
fprintf(stderr, "file_ram_alloc: failed to preallocate pages\n");
exit(1);
}
/* MAP_POPULATE silently ignores failures */
for (i = 0; i < (memory/hpagesize)-1; i++) {
memset(area + (hpagesize*i), 0, 1);
}
ret = sigaction(SIGBUS, &oldact, NULL);
if (ret) {
perror("file_ram_alloc: failed to reinstall signal handler");
exit(1);
}
pthread_sigmask(SIG_SETMASK, &oldset, NULL);
}
block->fd = fd;
return area;
}