On Sun, Sep 12, 2010 at 12:55 PM, Andreas Färber <andreas.faer...@web.de> wrote:
> From: Andreas Färber <afaer...@opensolaris.org>
>
> vl.c has a Sun-specific hack to supply a prototype for madvise(),
> but the call site has apparently moved to arch_init.c.
>
> Haiku doesn't implement madvise() in favor of posix_madvise().
> OpenBSD and Solaris 10 don't implement posix_madvise() but madvise().
>
> Check for madvise() and posix_madvise() in configure and supply qemu_madvise()
> as wrapper. Prefer madvise() over posix_madvise() due to flag availability.
> Convert all callers to use qemu_madvise() and QEMU_MADV_*. No functional
> change
> except for arch_init.c:ram_load() now potentially falling back to
> posix_madvise()
> or no-op in lack of both.
>
> v2 -> v3:
> * Reuse the *_MADV_* defines for QEMU_MADV_*. Suggested by Alexander Graf.
> * Add configure check for madvise(), too.
> Add defines to Makefile, not QEMU_CFLAGS.
> Convert all callers, untested. Suggested by Blue Swirl.
> * Keep Solaris' madvise() prototype around. Pointed out by Alexander Graf.
>
> v1 -> v2:
> * Don't rely on posix_madvise() availability, add qemu_madvise().
> Suggested by Blue Swirl.
>
> Signed-off-by: Andreas Färber <afaer...@opensolaris.org>
> Cc: Blue Swirl <blauwir...@gmail.com>
> Cc: Alexander Graf <ag...@suse.de>
> ---
> arch_init.c | 2 +-
> configure | 33 +++++++++++++++++++++++++++++++++
> exec.c | 8 ++++----
> hw/virtio-balloon.c | 4 ++--
> kvm-all.c | 6 +++---
> osdep.c | 15 +++++++++++++++
> osdep.h | 25 +++++++++++++++++++++++++
> vl.c | 3 ---
> 8 files changed, 83 insertions(+), 13 deletions(-)
>
> diff --git a/arch_init.c b/arch_init.c
> index e468c0c..a910033 100644
> --- a/arch_init.c
> +++ b/arch_init.c
> @@ -396,7 +396,7 @@ int ram_load(QEMUFile *f, void *opaque, int version_id)
> #ifndef _WIN32
> if (ch == 0 &&
> (!kvm_enabled() || kvm_has_sync_mmu())) {
> - madvise(host, TARGET_PAGE_SIZE, MADV_DONTNEED);
> + qemu_madvise(host, TARGET_PAGE_SIZE, QEMU_MADV_DONTNEED);
> }
> #endif
> } else if (flags & RAM_SAVE_FLAG_PAGE) {
> diff --git a/configure b/configure
> index 4061cb7..86558eb 100755
> --- a/configure
> +++ b/configure
> @@ -2069,6 +2069,31 @@ if compile_prog "" "" ; then
> fi
>
> ##########################################
> +# check if we have madvise
> +
> +madvise=no
> +cat > $TMPC << EOF
> +#include <sys/types.h>
> +#include <sys/mman.h>
> +int main(void) { return madvise(NULL, 0, MADV_DONTNEED); }
> +EOF
> +if compile_prog "" "" ; then
> + madvise=yes
> +fi
> +
> +##########################################
> +# check if we have posix_madvise
> +
> +posix_madvise=no
> +cat > $TMPC << EOF
> +#include <sys/mman.h>
> +int main(void) { return posix_madvise(NULL, 0, POSIX_MADV_DONTNEED); }
> +EOF
> +if compile_prog "" "" ; then
> + posix_madvise=yes
> +fi
> +
> +##########################################
> # check if trace backend exists
>
> sh "$source_path/tracetool" "--$trace_backend" --check-backend > /dev/null
> 2> /dev/null
> @@ -2226,6 +2251,8 @@ echo "KVM support $kvm"
> echo "fdt support $fdt"
> echo "preadv support $preadv"
> echo "fdatasync $fdatasync"
> +echo "madvise $madvise"
> +echo "posix_madvise $posix_madvise"
> echo "uuid support $uuid"
> echo "vhost-net support $vhost_net"
> echo "Trace backend $trace_backend"
> @@ -2466,6 +2493,12 @@ fi
> if test "$fdatasync" = "yes" ; then
> echo "CONFIG_FDATASYNC=y" >> $config_host_mak
> fi
> +if test "$madvise" = "yes" ; then
> + echo "CONFIG_MADVISE=y" >> $config_host_mak
> +fi
> +if test "$posix_madvise" = "yes" ; then
> + echo "CONFIG_POSIX_MADVISE=y" >> $config_host_mak
> +fi
>
> # XXX: suppress that
> if [ "$bsd" = "yes" ] ; then
> diff --git a/exec.c b/exec.c
> index 380dab5..b1fe3e9 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -2841,8 +2841,8 @@ ram_addr_t qemu_ram_alloc_from_ptr(DeviceState *dev,
> const char *name,
> new_block->host = file_ram_alloc(new_block, size, mem_path);
> if (!new_block->host) {
> new_block->host = qemu_vmalloc(size);
> -#ifdef MADV_MERGEABLE
> - madvise(new_block->host, size, MADV_MERGEABLE);
> +#ifdef QEMU_MADV_MERGEABLE
I'd like to avoid these #ifdefs. How about always #defining
QEMU_MADV_MERGEABLE? QEMU_MADV_* values could be synthetic and not
rely on MADV_*.
> + qemu_madvise(new_block->host, size, QEMU_MADV_MERGEABLE);
> #endif
> }
> #else
> @@ -2858,8 +2858,8 @@ ram_addr_t qemu_ram_alloc_from_ptr(DeviceState *dev,
> const char *name,
> #else
> new_block->host = qemu_vmalloc(size);
> #endif
> -#ifdef MADV_MERGEABLE
> - madvise(new_block->host, size, MADV_MERGEABLE);
> +#ifdef QEMU_MADV_MERGEABLE
> + qemu_madvise(new_block->host, size, QEMU_MADV_MERGEABLE);
> #endif
> }
> }
> diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c
> index 9fe3886..1e74674 100644
> --- a/hw/virtio-balloon.c
> +++ b/hw/virtio-balloon.c
> @@ -51,8 +51,8 @@ static void balloon_page(void *addr, int deflate)
> {
> #if defined(__linux__)
> if (!kvm_enabled() || kvm_has_sync_mmu())
> - madvise(addr, TARGET_PAGE_SIZE,
> - deflate ? MADV_WILLNEED : MADV_DONTNEED);
> + qemu_madvise(addr, TARGET_PAGE_SIZE,
> + deflate ? QEMU_MADV_WILLNEED : QEMU_MADV_DONTNEED);
> #endif
> }
>
> diff --git a/kvm-all.c b/kvm-all.c
> index 58b0404..9393419 100644
> --- a/kvm-all.c
> +++ b/kvm-all.c
> @@ -1031,11 +1031,11 @@ int kvm_has_xcrs(void)
> void kvm_setup_guest_memory(void *start, size_t size)
> {
> if (!kvm_has_sync_mmu()) {
> -#ifdef MADV_DONTFORK
> - int ret = madvise(start, size, MADV_DONTFORK);
> +#ifdef QEMU_MADV_DONTFORK
> + int ret = qemu_madvise(start, size, QEMU_MADV_DONTFORK);
>
> if (ret) {
> - perror("madvice");
> + perror("qemu_madvise");
> exit(1);
> }
> #else
Here the approach could be that if the return value is -ENOTSUP, we
don't print the error message. Then the #ifdefs could be dropped.
