| Message ID | 20220627135347.32624-2-ldufour@linux.ibm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Extending NMI watchdog during LPM | expand |
Le 12/07/2022 à 03:33, Nicholas Piggin a écrit : > Excerpts from Laurent Dufour's message of June 27, 2022 11:53 pm: >> In pseries_migration_partition(), loop until the memory transfer is >> complete. This way the calling drmgr process will not exit earlier, >> allowing callbacks to be run only once the migration is fully completed. >> >> If reading the VASI state is done after the hypervisor has completed the >> migration, the HCALL is returning H_PARAMETER. We can safely assume that >> the memory transfer is achieved if this happens. >> >> This will also allow to manage the NMI watchdog state in the next commits. >> >> Reviewed-by: Nathan Lynch <nathanl@linux.ibm.com> >> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com> >> --- >> arch/powerpc/platforms/pseries/mobility.c | 42 +++++++++++++++++++++-- >> 1 file changed, 40 insertions(+), 2 deletions(-) >> >> diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c >> index 78f3f74c7056..907a779074d6 100644 >> --- a/arch/powerpc/platforms/pseries/mobility.c >> +++ b/arch/powerpc/platforms/pseries/mobility.c >> @@ -427,6 +427,43 @@ static int wait_for_vasi_session_suspending(u64 handle) >> return ret; >> } >> >> +static void wait_for_vasi_session_completed(u64 handle) >> +{ >> + unsigned long state = 0; >> + int ret; >> + >> + pr_info("waiting for memory transfert to complete...\n"); > > ^ extra t (also below) I tried to push one French word, but you caught it ;) Will fix that and the other ones. >> + >> + /* >> + * Wait for transition from H_VASI_RESUMED to H_VASI_COMPLETED. >> + */ >> + while (true) { >> + ret = poll_vasi_state(handle, &state); >> + >> + /* >> + * If the memory transfer is already complete and the migration >> + * has been cleaned up by the hypervisor, H_PARAMETER is return, >> + * which is translate in EINVAL by poll_vasi_state(). >> + */ >> + if (ret == -EINVAL || (!ret && state == H_VASI_COMPLETED)) { >> + pr_info("memory transfert completed.\n"); >> + break; >> + } >> + >> + if (ret) { >> + pr_err("H_VASI_STATE return error (%d)\n", ret); >> + break; >> + } >> + >> + if (state != H_VASI_RESUMED) { >> + pr_err("unexpected H_VASI_STATE result %lu\n", state); >> + break; >> + } >> + >> + msleep(500); > > Is 500 specified anywhere? Another caller uses 1000, and the other one > uses some backoff interval starting at 1ms... This is a bit empiric, the idea is to wait for the overall memory transfer to be done. There is no real need to interact immediately after the operation is terminated, so I pick that value to not make too many Hcalls just for that. From the test I did, that seems to be a reasonable choice. > >> + } >> +} >> + >> static void prod_single(unsigned int target_cpu) >> { >> long hvrc; >> @@ -673,9 +710,10 @@ static int pseries_migrate_partition(u64 handle) >> vas_migration_handler(VAS_SUSPEND); >> >> ret = pseries_suspend(handle); >> - if (ret == 0) >> + if (ret == 0) { >> post_mobility_fixup(); >> - else >> + wait_for_vasi_session_completed(handle); > > If this wasn't required until later patches, maybe a comment about why > it's here? Could call it wait_for_migration() or similar too. > > Looks okay though from my basic reading of PAPR. > > Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Thanks Nick for reviewing this series. > >> + } else >> pseries_cancel_migration(handle, ret); >> >> vas_migration_handler(VAS_RESUME); >> -- >> 2.36.1 >> >>
diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c index 78f3f74c7056..907a779074d6 100644 --- a/arch/powerpc/platforms/pseries/mobility.c +++ b/arch/powerpc/platforms/pseries/mobility.c @@ -427,6 +427,43 @@ static int wait_for_vasi_session_suspending(u64 handle) return ret; } +static void wait_for_vasi_session_completed(u64 handle) +{ + unsigned long state = 0; + int ret; + + pr_info("waiting for memory transfert to complete...\n"); + + /* + * Wait for transition from H_VASI_RESUMED to H_VASI_COMPLETED. + */ + while (true) { + ret = poll_vasi_state(handle, &state); + + /* + * If the memory transfer is already complete and the migration + * has been cleaned up by the hypervisor, H_PARAMETER is return, + * which is translate in EINVAL by poll_vasi_state(). + */ + if (ret == -EINVAL || (!ret && state == H_VASI_COMPLETED)) { + pr_info("memory transfert completed.\n"); + break; + } + + if (ret) { + pr_err("H_VASI_STATE return error (%d)\n", ret); + break; + } + + if (state != H_VASI_RESUMED) { + pr_err("unexpected H_VASI_STATE result %lu\n", state); + break; + } + + msleep(500); + } +} + static void prod_single(unsigned int target_cpu) { long hvrc; @@ -673,9 +710,10 @@ static int pseries_migrate_partition(u64 handle) vas_migration_handler(VAS_SUSPEND); ret = pseries_suspend(handle); - if (ret == 0) + if (ret == 0) { post_mobility_fixup(); - else + wait_for_vasi_session_completed(handle); + } else pseries_cancel_migration(handle, ret); vas_migration_handler(VAS_RESUME);