Author: nwhitehorn
Date: Mon May 16 03:22:41 2011
New Revision: 221979
URL: http://svn.freebsd.org/changeset/base/221979
Log:
First draft of power hypervisor page replacement algorithm.
Modified:
projects/pseries/powerpc/pseries/mmu_phyp.c
Modified: projects/pseries/powerpc/pseries/mmu_phyp.c
==============================================================================
--- projects/pseries/powerpc/pseries/mmu_phyp.c Sun May 15 23:54:45 2011 (r221978)
+++ projects/pseries/powerpc/pseries/mmu_phyp.c Mon May 16 03:22:41 2011 (r221979)
@@ -218,11 +218,45 @@ mphyp_pte_change(mmu_t mmu, uintptr_t sl
panic("mphyp_pte_change() insertion failure: %ld\n", result);
}
+static __inline int
+mphyp_pte_spillable_ident(u_int ptegidx, struct lpte *to_evict)
+{
+ uint64_t slot, junk, k;
+ struct lpte pt;
+ int i, j;
+
+ /* Start at a random slot */
+ i = mftb() % 8;
+ k = -1;
+ for (j = 0; j < 8; j++) {
+ slot = (ptegidx << 3) + (i + j) % 8;
+ phyp_pft_hcall(H_READ, 0, slot, 0, 0, &pt.pte_hi, &pt.pte_lo,
+ &junk);
+
+ if (pt.pte_hi & (LPTE_LOCKED | LPTE_WIRED))
+ continue;
+
+ /* This is a candidate, so remember it */
+ k = slot;
+
+ /* Try to get a page that has not been used lately */
+ if (!(pt.pte_lo & LPTE_REF)) {
+ memcpy(to_evict, &pt, sizeof(struct lpte));
+ return (k);
+ }
+ }
+
+ phyp_pft_hcall(H_READ, 0, slot, 0, 0, &to_evict->pte_hi,
+ &to_evict->pte_lo, &junk);
+ return (k);
+}
+
static int
mphyp_pte_insert(mmu_t mmu, u_int ptegidx, struct lpte *pvo_pt)
{
int64_t result;
struct lpte evicted;
+ struct pvo_entry *pvo;
uint64_t index, junk;
u_int pteg_bktidx;
@@ -238,9 +272,12 @@ mphyp_pte_insert(mmu_t mmu, u_int ptegid
pvo_pt->pte_lo, &index, &evicted.pte_lo, &junk);
if (result == H_SUCCESS)
return (index & 0x07);
+ KASSERT(result == H_PTEG_FULL, ("Page insertion error: %ld "
+ "(ptegidx: %#x/%#x, PTE %#lx/%#lx", result, ptegidx,
+ moea64_pteg_count, pvo_pt->pte_hi, pvo_pt->pte_lo));
/*
- * First try primary hash.
+ * Next try secondary hash.
*/
pteg_bktidx ^= moea64_pteg_mask;
pvo_pt->pte_hi |= LPTE_HID;
@@ -248,8 +285,62 @@ mphyp_pte_insert(mmu_t mmu, u_int ptegid
pvo_pt->pte_hi, pvo_pt->pte_lo, &index, &evicted.pte_lo, &junk);
if (result == H_SUCCESS)
return (index & 0x07);
+ KASSERT(result == H_PTEG_FULL, ("Secondary page insertion error: %ld",
+ result));
+
+ /*
+ * Out of luck. Find a PTE to sacrifice.
+ */
+ pteg_bktidx = ptegidx;
+ index = mphyp_pte_spillable_ident(pteg_bktidx, &evicted);
+ if (index == -1L) {
+ pteg_bktidx ^= moea64_pteg_mask;
+ index = mphyp_pte_spillable_ident(pteg_bktidx, &evicted);
+ }
+
+ if (index == -1L) {
+ /* No freeable slots in either PTEG? We're hosed. */
+ panic("mphyp_pte_insert: overflow");
+ return (-1);
+ }
+
+ if (pteg_bktidx == ptegidx)
+ pvo_pt->pte_hi &= ~LPTE_HID;
+ else
+ pvo_pt->pte_hi |= LPTE_HID;
+
+ /*
+ * Synchronize the sacrifice PTE with its PVO, then mark both
+ * invalid. The PVO will be reused when/if the VM system comes
+ * here after a fault.
+ */
+
+ if (evicted.pte_hi & LPTE_HID)
+ pteg_bktidx ^= moea64_pteg_mask; /* PTEs indexed by primary */
+
+ LIST_FOREACH(pvo, &moea64_pvo_table[pteg_bktidx], pvo_olink) {
+ if (pvo->pvo_pte.lpte.pte_hi == evicted.pte_hi) {
+ KASSERT(pvo->pvo_pte.lpte.pte_hi & LPTE_VALID,
+ ("Invalid PVO for valid PTE!"));
+ phyp_hcall(H_REMOVE, 0, index, 0);
+ PVO_PTEGIDX_CLR(pvo);
+ moea64_pte_overflow++;
+ break;
+ }
+ }
+
+ KASSERT(pvo->pvo_pte.lpte.pte_hi == evicted.pte_hi,
+ ("Unable to find PVO for spilled PTE"));
+
+ /*
+ * Set the new PTE.
+ */
+ result = phyp_pft_hcall(H_ENTER, H_EXACT, index, pvo_pt->pte_hi,
+ pvo_pt->pte_lo, &index, &evicted.pte_lo, &junk);
+ if (result == H_SUCCESS)
+ return (index & 0x07);
- panic("OVERFLOW (%ld)", result);
+ panic("Page replacement error: %ld", result);
return (-1);
}