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powerpc/mm/hash: Reduce contention on hpte lock

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We do this in some part. This patch make sure we always try to search
for hpte without holding lock and redo the compare with lock held once
match found.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Aneesh Kumar K.V 2018-06-29 14:06:31 +05:30 committed by Michael Ellerman
parent a833280b4a
commit 27d8959da7
1 changed files with 33 additions and 16 deletions
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49
arch/powerpc/mm/hash_native_64.c
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@ -568,9 +568,19 @@ static void native_hpte_invalidate(unsigned long slot, unsigned long vpn,
DBG_LOW(" invalidate(vpn=%016lx, hash: %lx)\n", vpn, slot);
want_v = hpte_encode_avpn(vpn, bpsize, ssize);
native_lock_hpte(hptep);
hpte_v = hpte_get_old_v(hptep);
if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) {
native_lock_hpte(hptep);
/* recheck with locks held */
hpte_v = hpte_get_old_v(hptep);
if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID))
/* Invalidate the hpte. NOTE: this also unlocks it */
hptep->v = 0;
else
native_unlock_hpte(hptep);
}
/*
* We need to invalidate the TLB always because hpte_remove doesn't do
* a tlb invalidate. If a hash bucket gets full, we "evict" a more/less
@ -578,13 +588,6 @@ static void native_hpte_invalidate(unsigned long slot, unsigned long vpn,
* (hpte_remove) because we assume the old translation is still
* technically "valid".
*/
if (!HPTE_V_COMPARE(hpte_v, want_v) || !(hpte_v & HPTE_V_VALID))
native_unlock_hpte(hptep);
else
/* Invalidate the hpte. NOTE: this also unlocks it */
hptep->v = 0;
/* Invalidate the TLB */
tlbie(vpn, bpsize, apsize, ssize, local);
local_irq_restore(flags);
@ -626,15 +629,23 @@ static void native_hugepage_invalidate(unsigned long vsid,
hptep = htab_address + slot;
want_v = hpte_encode_avpn(vpn, psize, ssize);
native_lock_hpte(hptep);
hpte_v = hpte_get_old_v(hptep);
/* Even if we miss, we need to invalidate the TLB */
if (!HPTE_V_COMPARE(hpte_v, want_v) || !(hpte_v & HPTE_V_VALID))
native_unlock_hpte(hptep);
else
/* Invalidate the hpte. NOTE: this also unlocks it */
hptep->v = 0;
if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) {
/* recheck with locks held */
native_lock_hpte(hptep);
hpte_v = hpte_get_old_v(hptep);
if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) {
/*
* Invalidate the hpte. NOTE: this also unlocks it
*/
hptep->v = 0;
} else
native_unlock_hpte(hptep);
}
/*
* We need to do tlb invalidate for all the address, tlbie
* instruction compares entry_VA in tlb with the VA specified
@ -802,13 +813,19 @@ static void native_flush_hash_range(unsigned long number, int local)
slot += hidx & _PTEIDX_GROUP_IX;
hptep = htab_address + slot;
want_v = hpte_encode_avpn(vpn, psize, ssize);
hpte_v = hpte_get_old_v(hptep);
if (!HPTE_V_COMPARE(hpte_v, want_v) || !(hpte_v & HPTE_V_VALID))
continue;
/* lock and try again */
native_lock_hpte(hptep);
hpte_v = hpte_get_old_v(hptep);
if (!HPTE_V_COMPARE(hpte_v, want_v) ||
!(hpte_v & HPTE_V_VALID))
if (!HPTE_V_COMPARE(hpte_v, want_v) || !(hpte_v & HPTE_V_VALID))
native_unlock_hpte(hptep);
else
hptep->v = 0;
} pte_iterate_hashed_end();
}