Presuming that we lookup the memtype of an address far more often than
we modify the PAT ranges, favour the reader.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
---
arch/x86/mm/pat.c | 20 ++++++++++----------
1 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 18d4aa9..8cc67e5 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -130,7 +130,7 @@ void pat_init(void)
#undef PAT
-static DEFINE_SPINLOCK(memtype_lock); /* protects memtype accesses */
+static DEFINE_RWLOCK(memtype_lock); /* protects memtype accesses */
/*
* Does intersection of PAT memory type and MTRR memory type and returns
@@ -310,7 +310,7 @@ int reserve_memtype(u64 start, u64 end, unsigned long
req_type,
new->end = end;
new->type = actual_type;
- spin_lock(&memtype_lock);
+ write_lock(&memtype_lock);
err = rbt_memtype_check_insert(new, new_type);
if (err) {
@@ -318,12 +318,12 @@ int reserve_memtype(u64 start, u64 end, unsigned long
req_type,
"track %s, req %s\n",
start, end, cattr_name(new->type), cattr_name(req_type));
kfree(new);
- spin_unlock(&memtype_lock);
+ write_unlock(&memtype_lock);
return err;
}
- spin_unlock(&memtype_lock);
+ write_unlock(&memtype_lock);
dprintk("reserve_memtype added 0x%Lx-0x%Lx, track %s, req %s, ret %s\n",
start, end, cattr_name(new->type), cattr_name(req_type),
@@ -355,9 +355,9 @@ int free_memtype(u64 start, u64 end)
return -EINVAL;
}
- spin_lock(&memtype_lock);
+ write_lock(&memtype_lock);
entry = rbt_memtype_erase(start, end);
- spin_unlock(&memtype_lock);
+ write_unlock(&memtype_lock);
if (!entry) {
printk(KERN_INFO "%s:%d freeing invalid memtype %Lx-%Lx\n",
@@ -390,13 +390,13 @@ static unsigned long lookup_memtype(u64 paddr)
if (x86_platform.is_untracked_pat_range(paddr, paddr + PAGE_SIZE))
return _PAGE_CACHE_WB;
- spin_lock(&memtype_lock);
+ read_lock(&memtype_lock);
entry = rbt_memtype_lookup(paddr);
if (entry != NULL)
rettype = entry->type;
- spin_unlock(&memtype_lock);
+ read_unlock(&memtype_lock);
if (rettype != -1)
return rettype;
@@ -754,9 +754,9 @@ static struct memtype *memtype_get_idx(loff_t pos)
if (!print_entry)
return NULL;
- spin_lock(&memtype_lock);
+ read_lock(&memtype_lock);
ret = rbt_memtype_copy_nth_element(print_entry, pos);
- spin_unlock(&memtype_lock);
+ read_unlock(&memtype_lock);
if (!ret) {
return print_entry;
--
1.7.5.4
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