-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 01/15/2015 02:19 PM, Oleg Nesterov wrote: > interrupted_kernel_fpu_idle() tries to detect if > kernel_fpu_begin() is safe or not. In particular it should > obviously deny the nested kernel_fpu_begin() and this logic looks > very confusing. > > If use_eager_fpu() == T we rely on a) __thread_has_fpu() check in > interrupted_kernel_fpu_idle(), and b) on the fact that _begin() > does __thread_clear_has_fpu(). > > Otherwise we demand that the interrupted task has no FPU if it is > in kernel mode, this works because __kernel_fpu_begin() does clts() > and interrupted_kernel_fpu_idle() checks X86_CR0_TS. > > Add the per-cpu "bool in_kernel_fpu" variable, and change this > code to check/set/clear it. This allows to do more cleanups and > fixes, see the next changes. > > The patch also moves WARN_ON_ONCE() under preempt_disable() just > to make this_cpu_read() look better, this is not really needed. And > in fact I think we should move it into __kernel_fpu_begin(). > > Signed-off-by: Oleg Nesterov <o...@redhat.com>
Reviewed-by: Rik van Riel <r...@redhat.com> - -- All rights reversed -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJUuHXTAAoJEM553pKExN6Di2kIAL4HZ8qbOhHOaNKBvAA7uvdj 3uFZcDdgoviKKT5yi4Q/49+AvXulKVxLuwpZoZXy74wID2J2AQ1bEiVkUKXhhbrl 4FKW412VAD61fsAXvGp4n3l++ITTfjX4rL0hk6ntJlegqnI3l2sEYIWGa+Hnlh7e nTabtEOl3Ib1rkIKlR+6wVgogTzzLxLboGKY0aHHqYZmhlbGzWvnJ04PkgWPGFND 9rQWz/+ZhbBgpeQRQSW8syluswcs/gQah3BygIRnPFW500zDQzihxjssDSd7/X2Z 3lYq+TCWab8EGSpc4kOqgq+LU8nXxggP9nIA7LplqgpnIdAyg4YrxLvyWL5Y2Ys= =t5LD -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
