From f52862f4070fb930e407d466aa82d8efcc98c9ed Mon Sep 17 00:00:00 2001 From: Brian King Date: Tue, 17 Feb 2009 06:49:50 +0000 Subject: [PATCH] powerpc/pseries: Fix partition migration hang under load While testing partition migration with heavy CPU load using shared processors, it was observed that sometimes the migration would never complete and would appear to hang. Currently, the migration code assumes that if H_SUCCESS is returned from the H_JOIN then the migration is complete and the processor is waking up on the target system. If there was an outstanding PROD to the processor when the H_JOIN is called, however, it will return H_SUCCESS on the source system, causing the migration to hang, or in some scenarios cause the kernel to crash on the complete call waking the caller of rtas_percpu_suspend_me. Fix this by calling H_JOIN multiple times if necessary during the migration. Signed-off-by: Brian King Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/rtas.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index fdfe14c4bdef..ee4c7609b649 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -46,6 +46,7 @@ EXPORT_SYMBOL(rtas); struct rtas_suspend_me_data { atomic_t working; /* number of cpus accessing this struct */ + atomic_t done; int token; /* ibm,suspend-me */ int error; struct completion *complete; /* wait on this until working == 0 */ @@ -689,7 +690,7 @@ static int ibm_suspend_me_token = RTAS_UNKNOWN_SERVICE; #ifdef CONFIG_PPC_PSERIES static void rtas_percpu_suspend_me(void *info) { - long rc; + long rc = H_SUCCESS; unsigned long msr_save; int cpu; struct rtas_suspend_me_data *data = @@ -701,7 +702,8 @@ static void rtas_percpu_suspend_me(void *info) msr_save = mfmsr(); mtmsr(msr_save & ~(MSR_EE)); - rc = plpar_hcall_norets(H_JOIN); + while (rc == H_SUCCESS && !atomic_read(&data->done)) + rc = plpar_hcall_norets(H_JOIN); mtmsr(msr_save); @@ -724,6 +726,9 @@ static void rtas_percpu_suspend_me(void *info) smp_processor_id(), rc); data->error = rc; } + + atomic_set(&data->done, 1); + /* This cpu did the suspend or got an error; in either case, * we need to prod all other other cpus out of join state. * Extra prods are harmless. @@ -766,6 +771,7 @@ static int rtas_ibm_suspend_me(struct rtas_args *args) } atomic_set(&data.working, 0); + atomic_set(&data.done, 0); data.token = rtas_token("ibm,suspend-me"); data.error = 0; data.complete = &done;