diff options
| author | Michael S. Tsirkin <mst@redhat.com> | 2015-12-02 21:14:12 +0200 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2015-12-02 22:38:23 +0200 |
| commit | 7197fb4058bcb68986bae2bb2c04d6370f3e7218 (patch) | |
| tree | c61e664c27278f8497fb9fec90cbb88383bf1d0e /util/oslib-posix.c | |
| parent | 0560b0e97df3da43651158c799c6d889f27529c3 (diff) | |
util/mmap-alloc: fix hugetlb support on ppc64
Since commit 8561c9244ddf1122d "exec: allocate PROT_NONE pages on top of
RAM", it is no longer possible to back guest RAM with hugepages on ppc64
hosts:
mmap(NULL, 285212672, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0x3fff57000000
mmap(0x3fff57000000, 268435456, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED, 19, 0) = -1 EBUSY (Device or resource busy)
This is because on ppc64, Linux fixes a page size for a virtual address
at mmap time, so we can't switch a range of memory from anonymous
small pages to hugetlbs with MAP_FIXED.
See commit d0f13e3c20b6fb73ccb467bdca97fa7cf5a574cd
("[POWERPC] Introduce address space "slices"") in Linux
history for the details.
Detect this and create the PROT_NONE mapping using the same fd.
Naturally, this makes the guard page bigger with hugetlbfs.
Based on patch by Greg Kurz.
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Tested-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'util/oslib-posix.c')
| -rw-r--r-- | util/oslib-posix.c | 24 |
1 files changed, 1 insertions, 23 deletions
diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 914cef5c2c..d25f6715c7 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -46,7 +46,6 @@ extern int daemon(int, int); #else # define QEMU_VMALLOC_ALIGN getpagesize() #endif -#define HUGETLBFS_MAGIC 0x958458f6 #include <termios.h> #include <unistd.h> @@ -65,7 +64,6 @@ extern int daemon(int, int); #ifdef CONFIG_LINUX #include <sys/syscall.h> -#include <sys/vfs.h> #endif #ifdef __FreeBSD__ @@ -340,26 +338,6 @@ static void sigbus_handler(int signal) siglongjmp(sigjump, 1); } -static size_t fd_getpagesize(int fd) -{ -#ifdef CONFIG_LINUX - struct statfs fs; - int ret; - - if (fd != -1) { - do { - ret = fstatfs(fd, &fs); - } while (ret != 0 && errno == EINTR); - - if (ret == 0 && fs.f_type == HUGETLBFS_MAGIC) { - return fs.f_bsize; - } - } -#endif - - return getpagesize(); -} - void os_mem_prealloc(int fd, char *area, size_t memory) { int ret; @@ -387,7 +365,7 @@ void os_mem_prealloc(int fd, char *area, size_t memory) exit(1); } else { int i; - size_t hpagesize = fd_getpagesize(fd); + size_t hpagesize = qemu_fd_getpagesize(fd); size_t numpages = DIV_ROUND_UP(memory, hpagesize); /* MAP_POPULATE silently ignores failures */ |