On Wed, Feb 12, 2025 at 05:48:46PM +0000, Daniel P. Berrangé wrote: > On Wed, Feb 12, 2025 at 12:38:23PM -0500, Peter Xu wrote: > > From: Daniil Tatianin <d-tatia...@yandex-team.ru> > > > > This will be used in the following commits to make it possible to only > > lock memory on fault instead of right away. > > > > Signed-off-by: Daniil Tatianin <d-tatia...@yandex-team.ru> > > Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru> > > Link: > > https://lore.kernel.org/r/20250212143920.1269754-2-d-tatia...@yandex-team.ru > > [peterx: fail os_mlock(on_fault=1) when not supported] > > [peterx: use G_GNUC_UNUSED instead of "(void)on_fault", per Dan] > > Signed-off-by: Peter Xu <pet...@redhat.com> > > --- > > meson.build | 6 ++++++ > > include/system/os-posix.h | 2 +- > > include/system/os-win32.h | 2 +- > > migration/postcopy-ram.c | 2 +- > > os-posix.c | 15 +++++++++++++-- > > system/vl.c | 2 +- > > 6 files changed, 23 insertions(+), 6 deletions(-) > > > > diff --git a/meson.build b/meson.build > > index 18cf9e2913..59953cbe6b 100644 > > --- a/meson.build > > +++ b/meson.build > > @@ -2885,6 +2885,12 @@ config_host_data.set('HAVE_MLOCKALL', > > cc.links(gnu_source_prefix + ''' > > return mlockall(MCL_FUTURE); > > }''')) > > > > +config_host_data.set('HAVE_MLOCK_ONFAULT', cc.links(gnu_source_prefix + ''' > > + #include <sys/mman.h> > > + int main(void) { > > + return mlockall(MCL_FUTURE | MCL_ONFAULT); > > + }''')) > > + > > have_l2tpv3 = false > > if get_option('l2tpv3').allowed() and have_system > > have_l2tpv3 = cc.has_type('struct mmsghdr', > > diff --git a/include/system/os-posix.h b/include/system/os-posix.h > > index b881ac6c6f..ce5b3bccf8 100644 > > --- a/include/system/os-posix.h > > +++ b/include/system/os-posix.h > > @@ -53,7 +53,7 @@ bool os_set_runas(const char *user_id); > > void os_set_chroot(const char *path); > > void os_setup_limits(void); > > void os_setup_post(void); > > -int os_mlock(void); > > +int os_mlock(bool on_fault); > > > > /** > > * qemu_alloc_stack: > > diff --git a/include/system/os-win32.h b/include/system/os-win32.h > > index b82a5d3ad9..bc623061d8 100644 > > --- a/include/system/os-win32.h > > +++ b/include/system/os-win32.h > > @@ -123,7 +123,7 @@ static inline bool is_daemonized(void) > > return false; > > } > > > > -static inline int os_mlock(void) > > +static inline int os_mlock(bool on_fault G_GNUC_UNUSED) > > So did this actually generate a warning ? We don' even need > G_GNUC_UNUSED unless we're actually seeing warnings about this.
I didn't try to hit a warning without it, as we can use different compilers and I thought the results could be different, even if I try it and it didn't raise a warning? I do see though that we have plenty of such uses in the current tree, though. Does it mean it's a broader question to ask, rather than this patch only? Thanks, -- Peter Xu
