[IA64] Kernel parameter for max number of concurrent global TLB purges

[linux-2.6-omap-h63xx.git] / arch / ia64 / mm / tlb.c

diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
index d41d6076ed03472f80bcf828b4efa96f6c53fb6f..1a8948fd002905c361b17d135292bb1c630a8909 100644 (file)
--- 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;