| Message ID | 1461585338-45863-1-git-send-email-dingel@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, 04/25 13:55, Dominik Dingel wrote: > While in the anonymous ram case we already take care of the right alignment > such an alignment gurantee does not exist for file backed ram allocation. s/gurantee/guarantee/ Otherwise looks good to me, Reviewed-by: Fam Zheng <famz@redhat.com> > > Instead, pagesize is used for alignment. On s390 this is not enough for gmap, > as we need to satisfy an alignment up to segments. > > Reported-by: Halil Pasic <pasic@linux.vnet.ibm.com> > Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> > > --- > > v2 -> v3: > Skipping additional variable and just use alignment of memory region. > As memory will not be backpropagated it is enough to round up to page_sizes. > > v1 -> v2: > While enforcing alignments we allow memory sizes on page_size. > On mmap the memory size will be round up to alignments. > > I thought about moving this alignment into qemu_ram_mmap but the result > was a lot of code churn, the other possibility was to create an additional > define ending up with two defines with the same semantics. > --- > exec.c | 5 +++-- > include/qemu/osdep.h | 13 +++++++++++++ > util/oslib-posix.c | 13 ------------- > 3 files changed, 16 insertions(+), 15 deletions(-) > > diff --git a/exec.c b/exec.c > index c4f9036..fc75266 100644 > --- a/exec.c > +++ b/exec.c > @@ -1296,7 +1296,7 @@ static void *file_ram_alloc(RAMBlock *block, > } > > page_size = qemu_fd_getpagesize(fd); > - block->mr->align = page_size; > + block->mr->align = MAX(page_size, QEMU_VMALLOC_ALIGN); > > if (memory < page_size) { > error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to " > @@ -1317,7 +1317,8 @@ static void *file_ram_alloc(RAMBlock *block, > perror("ftruncate"); > } > > - area = qemu_ram_mmap(fd, memory, page_size, block->flags & RAM_SHARED); > + area = qemu_ram_mmap(fd, memory, block->mr->align, > + block->flags & RAM_SHARED); > if (area == MAP_FAILED) { > error_setg_errno(errp, errno, > "unable to map backing store for guest RAM"); > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h > index 408783f..783270f 100644 > --- a/include/qemu/osdep.h > +++ b/include/qemu/osdep.h > @@ -247,6 +247,19 @@ void qemu_anon_ram_free(void *ptr, size_t size); > > #endif > > +#if defined(__linux__) && \ > + (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) > + /* Use 2 MiB alignment so transparent hugepages can be used by KVM. > + Valgrind does not support alignments larger than 1 MiB, > + therefore we need special code which handles running on Valgrind. */ > +# define QEMU_VMALLOC_ALIGN (512 * 4096) > +#elif defined(__linux__) && defined(__s390x__) > + /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ > +# define QEMU_VMALLOC_ALIGN (256 * 4096) > +#else > +# define QEMU_VMALLOC_ALIGN getpagesize() > +#endif > + > int qemu_madvise(void *addr, size_t len, int advice); > > int qemu_open(const char *name, int flags, ...); > diff --git a/util/oslib-posix.c b/util/oslib-posix.c > index 6cc4b8f..4adde93 100644 > --- a/util/oslib-posix.c > +++ b/util/oslib-posix.c > @@ -26,19 +26,6 @@ > * THE SOFTWARE. > */ > > -#if defined(__linux__) && \ > - (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) > - /* Use 2 MiB alignment so transparent hugepages can be used by KVM. > - Valgrind does not support alignments larger than 1 MiB, > - therefore we need special code which handles running on Valgrind. */ > -# define QEMU_VMALLOC_ALIGN (512 * 4096) > -#elif defined(__linux__) && defined(__s390x__) > - /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ > -# define QEMU_VMALLOC_ALIGN (256 * 4096) > -#else > -# define QEMU_VMALLOC_ALIGN getpagesize() > -#endif > - > #include "qemu/osdep.h" > #include <termios.h> > #include <termios.h> > -- > 2.6.6 > >
On Fri, 29 Apr 2016 15:32:22 +0800 Fam Zheng <famz@redhat.com> wrote: > On Mon, 04/25 13:55, Dominik Dingel wrote: > > While in the anonymous ram case we already take care of the right alignment > > such an alignment gurantee does not exist for file backed ram allocation. > > s/gurantee/guarantee/ > > Otherwise looks good to me, > > Reviewed-by: Fam Zheng <famz@redhat.com> Thank you very much! Paolo do you want me to fix the typo, add the r-b and resend the patch? > > > > Instead, pagesize is used for alignment. On s390 this is not enough for gmap, > > as we need to satisfy an alignment up to segments. > > > > Reported-by: Halil Pasic <pasic@linux.vnet.ibm.com> > > Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> > > > > --- > > > > v2 -> v3: > > Skipping additional variable and just use alignment of memory region. > > As memory will not be backpropagated it is enough to round up to page_sizes. > > > > v1 -> v2: > > While enforcing alignments we allow memory sizes on page_size. > > On mmap the memory size will be round up to alignments. > > > > I thought about moving this alignment into qemu_ram_mmap but the result > > was a lot of code churn, the other possibility was to create an additional > > define ending up with two defines with the same semantics. > > --- > > exec.c | 5 +++-- > > include/qemu/osdep.h | 13 +++++++++++++ > > util/oslib-posix.c | 13 ------------- > > 3 files changed, 16 insertions(+), 15 deletions(-) > > > > diff --git a/exec.c b/exec.c > > index c4f9036..fc75266 100644 > > --- a/exec.c > > +++ b/exec.c > > @@ -1296,7 +1296,7 @@ static void *file_ram_alloc(RAMBlock *block, > > } > > > > page_size = qemu_fd_getpagesize(fd); > > - block->mr->align = page_size; > > + block->mr->align = MAX(page_size, QEMU_VMALLOC_ALIGN); > > > > if (memory < page_size) { > > error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to " > > @@ -1317,7 +1317,8 @@ static void *file_ram_alloc(RAMBlock *block, > > perror("ftruncate"); > > } > > > > - area = qemu_ram_mmap(fd, memory, page_size, block->flags & RAM_SHARED); > > + area = qemu_ram_mmap(fd, memory, block->mr->align, > > + block->flags & RAM_SHARED); > > if (area == MAP_FAILED) { > > error_setg_errno(errp, errno, > > "unable to map backing store for guest RAM"); > > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h > > index 408783f..783270f 100644 > > --- a/include/qemu/osdep.h > > +++ b/include/qemu/osdep.h > > @@ -247,6 +247,19 @@ void qemu_anon_ram_free(void *ptr, size_t size); > > > > #endif > > > > +#if defined(__linux__) && \ > > + (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) > > + /* Use 2 MiB alignment so transparent hugepages can be used by KVM. > > + Valgrind does not support alignments larger than 1 MiB, > > + therefore we need special code which handles running on Valgrind. */ > > +# define QEMU_VMALLOC_ALIGN (512 * 4096) > > +#elif defined(__linux__) && defined(__s390x__) > > + /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ > > +# define QEMU_VMALLOC_ALIGN (256 * 4096) > > +#else > > +# define QEMU_VMALLOC_ALIGN getpagesize() > > +#endif > > + > > int qemu_madvise(void *addr, size_t len, int advice); > > > > int qemu_open(const char *name, int flags, ...); > > diff --git a/util/oslib-posix.c b/util/oslib-posix.c > > index 6cc4b8f..4adde93 100644 > > --- a/util/oslib-posix.c > > +++ b/util/oslib-posix.c > > @@ -26,19 +26,6 @@ > > * THE SOFTWARE. > > */ > > > > -#if defined(__linux__) && \ > > - (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) > > - /* Use 2 MiB alignment so transparent hugepages can be used by KVM. > > - Valgrind does not support alignments larger than 1 MiB, > > - therefore we need special code which handles running on Valgrind. */ > > -# define QEMU_VMALLOC_ALIGN (512 * 4096) > > -#elif defined(__linux__) && defined(__s390x__) > > - /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ > > -# define QEMU_VMALLOC_ALIGN (256 * 4096) > > -#else > > -# define QEMU_VMALLOC_ALIGN getpagesize() > > -#endif > > - > > #include "qemu/osdep.h" > > #include <termios.h> > > #include <termios.h> > > -- > > 2.6.6 > > > > >
On Fri, 04/29 10:26, Dominik Dingel wrote: > On Fri, 29 Apr 2016 15:32:22 +0800 > Fam Zheng <famz@redhat.com> wrote: > > > On Mon, 04/25 13:55, Dominik Dingel wrote: > > > While in the anonymous ram case we already take care of the right alignment > > > such an alignment gurantee does not exist for file backed ram allocation. > > > > s/gurantee/guarantee/ > > > > Otherwise looks good to me, > > > > Reviewed-by: Fam Zheng <famz@redhat.com> > > Thank you very much! > > Paolo do you want me to fix the typo, add the r-b and resend the patch? Paolo is still travelling this week, you can do that if you feel like to, or I guess he can fix it himself when applying later. Fam > > > > > > > Instead, pagesize is used for alignment. On s390 this is not enough for gmap, > > > as we need to satisfy an alignment up to segments. > > > > > > Reported-by: Halil Pasic <pasic@linux.vnet.ibm.com> > > > Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> > > > > > > --- > > > > > > v2 -> v3: > > > Skipping additional variable and just use alignment of memory region. > > > As memory will not be backpropagated it is enough to round up to page_sizes. > > > > > > v1 -> v2: > > > While enforcing alignments we allow memory sizes on page_size. > > > On mmap the memory size will be round up to alignments. > > > > > > I thought about moving this alignment into qemu_ram_mmap but the result > > > was a lot of code churn, the other possibility was to create an additional > > > define ending up with two defines with the same semantics. > > > --- > > > exec.c | 5 +++-- > > > include/qemu/osdep.h | 13 +++++++++++++ > > > util/oslib-posix.c | 13 ------------- > > > 3 files changed, 16 insertions(+), 15 deletions(-) > > > > > > diff --git a/exec.c b/exec.c > > > index c4f9036..fc75266 100644 > > > --- a/exec.c > > > +++ b/exec.c > > > @@ -1296,7 +1296,7 @@ static void *file_ram_alloc(RAMBlock *block, > > > } > > > > > > page_size = qemu_fd_getpagesize(fd); > > > - block->mr->align = page_size; > > > + block->mr->align = MAX(page_size, QEMU_VMALLOC_ALIGN); > > > > > > if (memory < page_size) { > > > error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to " > > > @@ -1317,7 +1317,8 @@ static void *file_ram_alloc(RAMBlock *block, > > > perror("ftruncate"); > > > } > > > > > > - area = qemu_ram_mmap(fd, memory, page_size, block->flags & RAM_SHARED); > > > + area = qemu_ram_mmap(fd, memory, block->mr->align, > > > + block->flags & RAM_SHARED); > > > if (area == MAP_FAILED) { > > > error_setg_errno(errp, errno, > > > "unable to map backing store for guest RAM"); > > > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h > > > index 408783f..783270f 100644 > > > --- a/include/qemu/osdep.h > > > +++ b/include/qemu/osdep.h > > > @@ -247,6 +247,19 @@ void qemu_anon_ram_free(void *ptr, size_t size); > > > > > > #endif > > > > > > +#if defined(__linux__) && \ > > > + (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) > > > + /* Use 2 MiB alignment so transparent hugepages can be used by KVM. > > > + Valgrind does not support alignments larger than 1 MiB, > > > + therefore we need special code which handles running on Valgrind. */ > > > +# define QEMU_VMALLOC_ALIGN (512 * 4096) > > > +#elif defined(__linux__) && defined(__s390x__) > > > + /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ > > > +# define QEMU_VMALLOC_ALIGN (256 * 4096) > > > +#else > > > +# define QEMU_VMALLOC_ALIGN getpagesize() > > > +#endif > > > + > > > int qemu_madvise(void *addr, size_t len, int advice); > > > > > > int qemu_open(const char *name, int flags, ...); > > > diff --git a/util/oslib-posix.c b/util/oslib-posix.c > > > index 6cc4b8f..4adde93 100644 > > > --- a/util/oslib-posix.c > > > +++ b/util/oslib-posix.c > > > @@ -26,19 +26,6 @@ > > > * THE SOFTWARE. > > > */ > > > > > > -#if defined(__linux__) && \ > > > - (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) > > > - /* Use 2 MiB alignment so transparent hugepages can be used by KVM. > > > - Valgrind does not support alignments larger than 1 MiB, > > > - therefore we need special code which handles running on Valgrind. */ > > > -# define QEMU_VMALLOC_ALIGN (512 * 4096) > > > -#elif defined(__linux__) && defined(__s390x__) > > > - /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ > > > -# define QEMU_VMALLOC_ALIGN (256 * 4096) > > > -#else > > > -# define QEMU_VMALLOC_ALIGN getpagesize() > > > -#endif > > > - > > > #include "qemu/osdep.h" > > > #include <termios.h> > > > #include <termios.h> > > > -- > > > 2.6.6 > > > > > > > > >
On 25/04/2016 13:55, Dominik Dingel wrote: > While in the anonymous ram case we already take care of the right alignment > such an alignment gurantee does not exist for file backed ram allocation. > > Instead, pagesize is used for alignment. On s390 this is not enough for gmap, > as we need to satisfy an alignment up to segments. > > Reported-by: Halil Pasic <pasic@linux.vnet.ibm.com> > Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Looks good now, thanks. Cc: qemu-stable <qemu-stable@nongnu.org> Paolo > --- > > v2 -> v3: > Skipping additional variable and just use alignment of memory region. > As memory will not be backpropagated it is enough to round up to page_sizes. > > v1 -> v2: > While enforcing alignments we allow memory sizes on page_size. > On mmap the memory size will be round up to alignments. > > I thought about moving this alignment into qemu_ram_mmap but the result > was a lot of code churn, the other possibility was to create an additional > define ending up with two defines with the same semantics. > --- > exec.c | 5 +++-- > include/qemu/osdep.h | 13 +++++++++++++ > util/oslib-posix.c | 13 ------------- > 3 files changed, 16 insertions(+), 15 deletions(-) > > diff --git a/exec.c b/exec.c > index c4f9036..fc75266 100644 > --- a/exec.c > +++ b/exec.c > @@ -1296,7 +1296,7 @@ static void *file_ram_alloc(RAMBlock *block, > } > > page_size = qemu_fd_getpagesize(fd); > - block->mr->align = page_size; > + block->mr->align = MAX(page_size, QEMU_VMALLOC_ALIGN); > > if (memory < page_size) { > error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to " > @@ -1317,7 +1317,8 @@ static void *file_ram_alloc(RAMBlock *block, > perror("ftruncate"); > } > > - area = qemu_ram_mmap(fd, memory, page_size, block->flags & RAM_SHARED); > + area = qemu_ram_mmap(fd, memory, block->mr->align, > + block->flags & RAM_SHARED); > if (area == MAP_FAILED) { > error_setg_errno(errp, errno, > "unable to map backing store for guest RAM"); > diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h > index 408783f..783270f 100644 > --- a/include/qemu/osdep.h > +++ b/include/qemu/osdep.h > @@ -247,6 +247,19 @@ void qemu_anon_ram_free(void *ptr, size_t size); > > #endif > > +#if defined(__linux__) && \ > + (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) > + /* Use 2 MiB alignment so transparent hugepages can be used by KVM. > + Valgrind does not support alignments larger than 1 MiB, > + therefore we need special code which handles running on Valgrind. */ > +# define QEMU_VMALLOC_ALIGN (512 * 4096) > +#elif defined(__linux__) && defined(__s390x__) > + /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ > +# define QEMU_VMALLOC_ALIGN (256 * 4096) > +#else > +# define QEMU_VMALLOC_ALIGN getpagesize() > +#endif > + > int qemu_madvise(void *addr, size_t len, int advice); > > int qemu_open(const char *name, int flags, ...); > diff --git a/util/oslib-posix.c b/util/oslib-posix.c > index 6cc4b8f..4adde93 100644 > --- a/util/oslib-posix.c > +++ b/util/oslib-posix.c > @@ -26,19 +26,6 @@ > * THE SOFTWARE. > */ > > -#if defined(__linux__) && \ > - (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) > - /* Use 2 MiB alignment so transparent hugepages can be used by KVM. > - Valgrind does not support alignments larger than 1 MiB, > - therefore we need special code which handles running on Valgrind. */ > -# define QEMU_VMALLOC_ALIGN (512 * 4096) > -#elif defined(__linux__) && defined(__s390x__) > - /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ > -# define QEMU_VMALLOC_ALIGN (256 * 4096) > -#else > -# define QEMU_VMALLOC_ALIGN getpagesize() > -#endif > - > #include "qemu/osdep.h" > #include <termios.h> > #include <termios.h> >
diff --git a/exec.c b/exec.c index c4f9036..fc75266 100644 --- a/exec.c +++ b/exec.c @@ -1296,7 +1296,7 @@ static void *file_ram_alloc(RAMBlock *block, } page_size = qemu_fd_getpagesize(fd); - block->mr->align = page_size; + block->mr->align = MAX(page_size, QEMU_VMALLOC_ALIGN); if (memory < page_size) { error_setg(errp, "memory size 0x" RAM_ADDR_FMT " must be equal to " @@ -1317,7 +1317,8 @@ static void *file_ram_alloc(RAMBlock *block, perror("ftruncate"); } - area = qemu_ram_mmap(fd, memory, page_size, block->flags & RAM_SHARED); + area = qemu_ram_mmap(fd, memory, block->mr->align, + block->flags & RAM_SHARED); if (area == MAP_FAILED) { error_setg_errno(errp, errno, "unable to map backing store for guest RAM"); diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h index 408783f..783270f 100644 --- a/include/qemu/osdep.h +++ b/include/qemu/osdep.h @@ -247,6 +247,19 @@ void qemu_anon_ram_free(void *ptr, size_t size); #endif +#if defined(__linux__) && \ + (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) + /* Use 2 MiB alignment so transparent hugepages can be used by KVM. + Valgrind does not support alignments larger than 1 MiB, + therefore we need special code which handles running on Valgrind. */ +# define QEMU_VMALLOC_ALIGN (512 * 4096) +#elif defined(__linux__) && defined(__s390x__) + /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ +# define QEMU_VMALLOC_ALIGN (256 * 4096) +#else +# define QEMU_VMALLOC_ALIGN getpagesize() +#endif + int qemu_madvise(void *addr, size_t len, int advice); int qemu_open(const char *name, int flags, ...); diff --git a/util/oslib-posix.c b/util/oslib-posix.c index 6cc4b8f..4adde93 100644 --- a/util/oslib-posix.c +++ b/util/oslib-posix.c @@ -26,19 +26,6 @@ * THE SOFTWARE. */ -#if defined(__linux__) && \ - (defined(__x86_64__) || defined(__arm__) || defined(__aarch64__)) - /* Use 2 MiB alignment so transparent hugepages can be used by KVM. - Valgrind does not support alignments larger than 1 MiB, - therefore we need special code which handles running on Valgrind. */ -# define QEMU_VMALLOC_ALIGN (512 * 4096) -#elif defined(__linux__) && defined(__s390x__) - /* Use 1 MiB (segment size) alignment so gmap can be used by KVM. */ -# define QEMU_VMALLOC_ALIGN (256 * 4096) -#else -# define QEMU_VMALLOC_ALIGN getpagesize() -#endif - #include "qemu/osdep.h" #include <termios.h> #include <termios.h>
While in the anonymous ram case we already take care of the right alignment such an alignment gurantee does not exist for file backed ram allocation. Instead, pagesize is used for alignment. On s390 this is not enough for gmap, as we need to satisfy an alignment up to segments. Reported-by: Halil Pasic <pasic@linux.vnet.ibm.com> Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> --- v2 -> v3: Skipping additional variable and just use alignment of memory region. As memory will not be backpropagated it is enough to round up to page_sizes. v1 -> v2: While enforcing alignments we allow memory sizes on page_size. On mmap the memory size will be round up to alignments. I thought about moving this alignment into qemu_ram_mmap but the result was a lot of code churn, the other possibility was to create an additional define ending up with two defines with the same semantics. --- exec.c | 5 +++-- include/qemu/osdep.h | 13 +++++++++++++ util/oslib-posix.c | 13 ------------- 3 files changed, 16 insertions(+), 15 deletions(-)