search for: __test_bit

...+ */ > > +#define __get_user_mm(mm, x, ptr) \ > > +({ \ > > + int ___gu_err = __get_user(x, ptr); \ > > + if (!___gu_err && test_bit(MMF_UNSTABLE, &mm->flags)) \ > > test_bit is somewhat expensive. See my old mail > x86/bitops: implement __test_bit Do you have a msg_id? > I dropped it as virtio just switched to simple &/| for features, > but we might need something like this now. Is this such a hot path that something like this would make a visible difference? > > > > > + ___gu_err = -EFAULT; \ > > +...

...+ */ > > +#define __get_user_mm(mm, x, ptr) \ > > +({ \ > > + int ___gu_err = __get_user(x, ptr); \ > > + if (!___gu_err && test_bit(MMF_UNSTABLE, &mm->flags)) \ > > test_bit is somewhat expensive. See my old mail > x86/bitops: implement __test_bit Do you have a msg_id? > I dropped it as virtio just switched to simple &/| for features, > but we might need something like this now. Is this such a hot path that something like this would make a visible difference? > > > > > + ___gu_err = -EFAULT; \ > > +...

From: Michal Hocko <mhocko at suse.com> vhost driver relies on copy_from_user/get_user from a kernel thread. This makes it impossible to reap the memory of an oom victim which shares mm with the vhost kernel thread because it could see a zero page unexpectedly and theoretically make an incorrect decision visible outside of the killed task context. Make sure that each place which can read

From: Michal Hocko <mhocko at suse.com> vhost driver relies on copy_from_user/get_user from a kernel thread. This makes it impossible to reap the memory of an oom victim which shares mm with the vhost kernel thread because it could see a zero page unexpectedly and theoretically make an incorrect decision visible outside of the killed task context. Make sure that each place which can read

...39;t reaped in the background > + */ > +#define __get_user_mm(mm, x, ptr) \ > +({ \ > + int ___gu_err = __get_user(x, ptr); \ > + if (!___gu_err && test_bit(MMF_UNSTABLE, &mm->flags)) \ test_bit is somewhat expensive. See my old mail x86/bitops: implement __test_bit I dropped it as virtio just switched to simple &/| for features, but we might need something like this now. > + ___gu_err = -EFAULT; \ > + ___gu_err; \ > +}) > + > +/* similar to __get_user_mm */ > +static inline __must_check long __copy_from_user_mm(struct mm_str...