From a6c75b86ce9f01db4ea9912877b526c2dc4d2f0a Mon Sep 17 00:00:00 2001 From: Fenghua Yu Date: Fri, 14 Mar 2008 13:57:08 -0700 Subject: [IA64] Kernel parameter for max number of concurrent global TLB purges The patch defines kernel parameter "nptcg=". The parameter overrides max number of concurrent global TLB purges which is reported from either PAL_VM_SUMMARY or SAL PALO. Signed-off-by: Fenghua Yu Signed-off-by: Tony Luck --- arch/ia64/mm/tlb.c | 46 +++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 41 insertions(+), 5 deletions(-) (limited to 'arch/ia64/mm') diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c index d41d6076ed0..1a8948fd002 100644 --- a/arch/ia64/mm/tlb.c +++ b/arch/ia64/mm/tlb.c @@ -119,6 +119,27 @@ static u16 nptcg = 1; static int need_ptcg_sem = 1; static int toolatetochangeptcgsem = 0; +/* + * Kernel parameter "nptcg=" overrides max number of concurrent global TLB + * purges which is reported from either PAL or SAL PALO. + * + * We don't have sanity checking for nptcg value. It's the user's responsibility + * for valid nptcg value on the platform. Otherwise, kernel may hang in some + * cases. + */ +static int __init +set_nptcg(char *str) +{ + int value = 0; + + get_option(&str, &value); + setup_ptcg_sem(value, NPTCG_FROM_KERNEL_PARAMETER); + + return 1; +} + +__setup("nptcg=", set_nptcg); + /* * Maximum number of simultaneous ptc.g purges in the system can * be defined by PAL_VM_SUMMARY (in which case we should take @@ -126,13 +147,18 @@ static int toolatetochangeptcgsem = 0; * override table (in which case we should ignore the value from * PAL_VM_SUMMARY). * + * Kernel parameter "nptcg=" overrides maximum number of simultanesous ptc.g + * purges defined in either PAL_VM_SUMMARY or PAL override table. In this case, + * we should ignore the value from either PAL_VM_SUMMARY or PAL override table. + * * Complicating the logic here is the fact that num_possible_cpus() * isn't fully setup until we start bringing cpus online. */ void -setup_ptcg_sem(int max_purges, int from_palo) +setup_ptcg_sem(int max_purges, int nptcg_from) { - static int have_palo; + static int kp_override; + static int palo_override; static int firstcpu = 1; if (toolatetochangeptcgsem) { @@ -140,8 +166,18 @@ setup_ptcg_sem(int max_purges, int from_palo) return; } - if (from_palo) { - have_palo = 1; + if (nptcg_from == NPTCG_FROM_KERNEL_PARAMETER) { + kp_override = 1; + nptcg = max_purges; + goto resetsema; + } + if (kp_override) { + need_ptcg_sem = num_possible_cpus() > nptcg; + return; + } + + if (nptcg_from == NPTCG_FROM_PALO) { + palo_override = 1; /* In PALO max_purges == 0 really means it! */ if (max_purges == 0) @@ -153,7 +189,7 @@ setup_ptcg_sem(int max_purges, int from_palo) } goto resetsema; } - if (have_palo) { + if (palo_override) { if (nptcg != PALO_MAX_TLB_PURGES) need_ptcg_sem = (num_possible_cpus() > nptcg); return; -- cgit v1.2.3