ia64: Reduce stack usage by iterating over nodemask

GCC complains about sn2_global_tlb_purge() because of the large stack
required by the function,

  arch/ia64/sn/kernel/sn2/sn2_smp.c: In function 'sn2_global_tlb_purge':
  arch/ia64/sn/kernel/sn2/sn2_smp.c:319:1: warning: the frame size of 2176 bytes is larger than 2048 bytes [-Wframe-larger-than=]

2048 bytes of the stack are consumed by the node ID array 'nasids[]'.
But we don't actually need to put the ID array on the stack and can
use nodemask operations.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Tony Luck <tony.luck@intel.com>

diff --git a/arch/ia64/sn/kernel/sn2/sn2_smp.c b/arch/ia64/sn/kernel/sn2/sn2_smp.c
index f9c8d9f..c98dc96 100644 (file)
--- a/arch/ia64/sn/kernel/sn2/sn2_smp.c
+++ b/arch/ia64/sn/kernel/sn2/sn2_smp.c
@@ -54,7 +54,7 @@ sn2_ptc_deadlock_recovery_core(volatile unsigned long *, unsigned long,
                               volatile unsigned long *, unsigned long,
                               volatile unsigned long *, unsigned long);
 void
-sn2_ptc_deadlock_recovery(short *, short, short, int,
+sn2_ptc_deadlock_recovery(nodemask_t, short, short, int,
                          volatile unsigned long *, unsigned long,
                          volatile unsigned long *, unsigned long);
 
@@ -169,7 +169,7 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
        int use_cpu_ptcga;
        volatile unsigned long *ptc0, *ptc1;
        unsigned long itc, itc2, flags, data0 = 0, data1 = 0, rr_value, old_rr = 0;
-       short nasids[MAX_NUMNODES], nix;
+       short nix;
        nodemask_t nodes_flushed;
        int active, max_active, deadlock, flush_opt = sn2_flush_opt;
 
@@ -218,9 +218,7 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
        }
 
        itc = ia64_get_itc();
-       nix = 0;
-       for_each_node_mask(cnode, nodes_flushed)
-               nasids[nix++] = cnodeid_to_nasid(cnode);
+       nix = nodes_weight(nodes_flushed);
 
        rr_value = (mm->context << 3) | REGION_NUMBER(start);
 
@@ -270,8 +268,10 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
                        data0 = (data0 & ~SH2_PTC_ADDR_MASK) | (start & SH2_PTC_ADDR_MASK);
                deadlock = 0;
                active = 0;
-               for (ibegin = 0, i = 0; i < nix; i++) {
-                       nasid = nasids[i];
+               ibegin = 0;
+               i = 0;
+               for_each_node_mask(cnode, nodes_flushed) {
+                       nasid = cnodeid_to_nasid(cnode);
                        if (use_cpu_ptcga && unlikely(nasid == mynasid)) {
                                ia64_ptcga(start, nbits << 2);
                                ia64_srlz_i();
@@ -286,13 +286,14 @@ sn2_global_tlb_purge(struct mm_struct *mm, unsigned long start,
                                if ((deadlock = wait_piowc())) {
                                        if (flush_opt == 1)
                                                goto done;
-                                       sn2_ptc_deadlock_recovery(nasids, ibegin, i, mynasid, ptc0, data0, ptc1, data1);
+                                       sn2_ptc_deadlock_recovery(nodes_flushed, ibegin, i, mynasid, ptc0, data0, ptc1, data1);
                                        if (reset_max_active_on_deadlock())
                                                max_active = 1;
                                }
                                active = 0;
                                ibegin = i + 1;
                        }
+                       i++;
                }
                start += (1UL << nbits);
        } while (start < end);
@@ -327,11 +328,12 @@ done:
  */
 
 void
-sn2_ptc_deadlock_recovery(short *nasids, short ib, short ie, int mynasid,
+sn2_ptc_deadlock_recovery(nodemask_t nodes, short ib, short ie, int mynasid,
                          volatile unsigned long *ptc0, unsigned long data0,
                          volatile unsigned long *ptc1, unsigned long data1)
 {
        short nasid, i;
+       int cnode;
        unsigned long *piows, zeroval, n;
 
        __this_cpu_inc(ptcstats.deadlocks);
@@ -339,17 +341,26 @@ sn2_ptc_deadlock_recovery(short *nasids, short ib, short ie, int mynasid,
        piows = (unsigned long *) pda->pio_write_status_addr;
        zeroval = pda->pio_write_status_val;
 
+       i = 0;
+       for_each_node_mask(cnode, nodes) {
+               if (i < ib)
+                       goto next;
+
+               if (i > ie)
+                       break;
 
-       for (i=ib; i <= ie; i++) {
-               nasid = nasids[i];
+               nasid = cnodeid_to_nasid(cnode);
                if (local_node_uses_ptc_ga(is_shub1()) && nasid == mynasid)
-                       continue;
+                       goto next;
+
                ptc0 = CHANGE_NASID(nasid, ptc0);
                if (ptc1)
                        ptc1 = CHANGE_NASID(nasid, ptc1);
 
                n = sn2_ptc_deadlock_recovery_core(ptc0, data0, ptc1, data1, piows, zeroval);
                __this_cpu_add(ptcstats.deadlocks2, n);
+next:
+               i++;
        }
 
 }