| Message ID | 1390229051-28635-8-git-send-email-pbonzini@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 20.01.2014, at 15:44, Paolo Bonzini <pbonzini@redhat.com> wrote: > From: thomas knych <thomaswk@google.com> > > Upstreaming this change from Android (https://android-review.googlesource.com/54211). > > On heavily loaded machines with many VM instances we see KVM_CREATE_VM > failing with EINTR on this path: > > kvm_dev_ioctl_create_vm -> kvm_create_vm -> kvm_init_mmu_notifier -> mmu_notifier_register -> do_mmu_notifier_register -> mm_take_all_locks > > which checks if any signals have been raised while it was attaining locks > and returns EINTR. Retrying the system call greatly improves reliability. > > Cc: qemu-stable@nongnu.org > Signed-off-by: thomas knych <thomaswk@google.com> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > kvm-all.c | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/kvm-all.c b/kvm-all.c > index 3937754..6df2ee1 100644 > --- a/kvm-all.c > +++ b/kvm-all.c > @@ -1442,16 +1442,22 @@ int kvm_init(void) > nc++; > } > > - s->vmfd = kvm_ioctl(s, KVM_CREATE_VM, 0); > - if (s->vmfd < 0) { > + do { > + ret = kvm_ioctl(s, KVM_CREATE_VM, 0); > + } while (ret == -EINTR); > + > + if (ret < 0) { > + fprintf(stderr, "ioctl(KVM_CREATE_VM) failed: %d %s\n", -s->vmfd, Shouldn't this be -ret? Alex > + strerror(-ret)); > + > #ifdef TARGET_S390X > fprintf(stderr, "Please add the 'switch_amode' kernel parameter to " > "your host kernel command line\n"); > #endif > - ret = s->vmfd; > goto err; > } > > + s->vmfd = ret; > missing_cap = kvm_check_extension_list(s, kvm_required_capabilites); > if (!missing_cap) { > missing_cap = > -- > 1.8.3.1 > > >
Il 27/01/2014 14:44, Alexander Graf ha scritto: > > On 20.01.2014, at 15:44, Paolo Bonzini <pbonzini@redhat.com> wrote: > >> From: thomas knych <thomaswk@google.com> >> >> Upstreaming this change from Android (https://android-review.googlesource.com/54211). >> >> On heavily loaded machines with many VM instances we see KVM_CREATE_VM >> failing with EINTR on this path: >> >> kvm_dev_ioctl_create_vm -> kvm_create_vm -> kvm_init_mmu_notifier -> mmu_notifier_register -> do_mmu_notifier_register -> mm_take_all_locks >> >> which checks if any signals have been raised while it was attaining locks >> and returns EINTR. Retrying the system call greatly improves reliability. >> >> Cc: qemu-stable@nongnu.org >> Signed-off-by: thomas knych <thomaswk@google.com> >> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> >> --- >> kvm-all.c | 12 +++++++++--- >> 1 file changed, 9 insertions(+), 3 deletions(-) >> >> diff --git a/kvm-all.c b/kvm-all.c >> index 3937754..6df2ee1 100644 >> --- a/kvm-all.c >> +++ b/kvm-all.c >> @@ -1442,16 +1442,22 @@ int kvm_init(void) >> nc++; >> } >> >> - s->vmfd = kvm_ioctl(s, KVM_CREATE_VM, 0); >> - if (s->vmfd < 0) { >> + do { >> + ret = kvm_ioctl(s, KVM_CREATE_VM, 0); >> + } while (ret == -EINTR); >> + >> + if (ret < 0) { >> + fprintf(stderr, "ioctl(KVM_CREATE_VM) failed: %d %s\n", -s->vmfd, > > Shouldn't this be -ret? Yes. Can you send a patch? Paolo
diff --git a/kvm-all.c b/kvm-all.c index 3937754..6df2ee1 100644 --- a/kvm-all.c +++ b/kvm-all.c @@ -1442,16 +1442,22 @@ int kvm_init(void) nc++; } - s->vmfd = kvm_ioctl(s, KVM_CREATE_VM, 0); - if (s->vmfd < 0) { + do { + ret = kvm_ioctl(s, KVM_CREATE_VM, 0); + } while (ret == -EINTR); + + if (ret < 0) { + fprintf(stderr, "ioctl(KVM_CREATE_VM) failed: %d %s\n", -s->vmfd, + strerror(-ret)); + #ifdef TARGET_S390X fprintf(stderr, "Please add the 'switch_amode' kernel parameter to " "your host kernel command line\n"); #endif - ret = s->vmfd; goto err; } + s->vmfd = ret; missing_cap = kvm_check_extension_list(s, kvm_required_capabilites); if (!missing_cap) { missing_cap =