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| author | Eric van Gyzen <vangyzen@FreeBSD.org> | 2021-04-26 15:01:17 +0000 |
|---|---|---|
| committer | Eric van Gyzen <vangyzen@FreeBSD.org> | 2021-04-30 18:32:29 +0000 |
| commit | 2f32a971b7f936170b4d61318238e6cf89f198b5 (patch) | |
| tree | 3f62a17d8816bce7194c88b1ce63a4017a840e77 | |
| parent | eda28feb2e070e21db3d50b3fc177f88380b8fb4 (diff) | |
| download | src-2f32a971b7f936170b4d61318238e6cf89f198b5.tar.gz src-2f32a971b7f936170b4d61318238e6cf89f198b5.zip | |
Wait longer for a previous IPI to be sent
When sending an IPI, if a previous IPI is still pending delivery,
native_lapic_ipi_vectored() waits for the previous IPI to be sent.
We've seen a few inexplicable panics with the current timeout of 50 ms.
Increase the timeout to 1 second and make it tunable.
No hardware specification mentions a timeout in this case; I checked
the Intel SDM, Intel MP spec, and Intel x2APIC spec. Linux and illumos
wait forever. In Linux, see __default_send_IPI_shortcut() in
arch/x86/kernel/apic/ipi.c. In illumos, see apic_send_ipi() in
usr/src/uts/i86pc/io/pcplusmp/apic_common.c. However, misbehaving hardware
could hang the system if we wait forever.
Reviewed by: mav kib
MFC after: 1 week
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D29942
| -rw-r--r-- | sys/x86/x86/local_apic.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/sys/x86/x86/local_apic.c b/sys/x86/x86/local_apic.c index 85c3cfb69277..36010fe38102 100644 --- a/sys/x86/x86/local_apic.c +++ b/sys/x86/x86/local_apic.c @@ -202,6 +202,7 @@ static u_long lapic_timer_divisor, count_freq; static struct eventtimer lapic_et; #ifdef SMP static uint64_t lapic_ipi_wait_mult; +static int __read_mostly lapic_ds_idle_timeout = 1000000; #endif unsigned int max_apic_id; @@ -212,6 +213,11 @@ SYSCTL_INT(_hw_apic, OID_AUTO, eoi_suppression, CTLFLAG_RD, &lapic_eoi_suppression, 0, ""); SYSCTL_INT(_hw_apic, OID_AUTO, timer_tsc_deadline, CTLFLAG_RD, &lapic_timer_tsc_deadline, 0, ""); +#ifdef SMP +SYSCTL_INT(_hw_apic, OID_AUTO, ds_idle_timeout, CTLFLAG_RWTUN, + &lapic_ds_idle_timeout, 0, + "timeout (in us) for APIC Delivery Status to become Idle (xAPIC only)"); +#endif static void lapic_calibrate_initcount(struct lapic *la); static void lapic_calibrate_deadline(struct lapic *la); @@ -2035,7 +2041,6 @@ native_lapic_ipi_raw(register_t icrlo, u_int dest) } } -#define BEFORE_SPIN 50000 #ifdef DETECT_DEADLOCK #define AFTER_SPIN 50 #endif @@ -2082,7 +2087,7 @@ native_lapic_ipi_vectored(u_int vector, int dest) icrlo |= APIC_DESTMODE_PHY | APIC_TRIGMOD_EDGE | APIC_LEVEL_ASSERT; /* Wait for an earlier IPI to finish. */ - if (!lapic_ipi_wait(BEFORE_SPIN)) { + if (!lapic_ipi_wait(lapic_ds_idle_timeout)) { if (KERNEL_PANICKED()) return; else |