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CapPtr: shift free lists to Alloc bounds

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This is incomplete, yet still more reflective of what's going on: we take the
exported pointers back from userspace and thread them directly into the free
lists.

So: move capptr_to_user_address_control to list construction time rather than
list consumption time.
This commit is contained in:
Nathaniel Wesley Filardo
2021-09-21 19:17:51 +01:00
committed by Nathaniel Wesley Filardo
parent 55cd5e87c0
commit 7e53a2e82a
7 changed files with 99 additions and 91 deletions
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41
src/mem/corealloc.h
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@@ -162,8 +162,8 @@ namespace snmalloc
// Manufacture an allocation to prime the queue
// Using an actual allocation removes a conditional from a critical path.
auto dummy =
capptr::AllocFull<void>(small_alloc_one(MIN_ALLOC_SIZE))
.template as_static<FreeObject::T<capptr::bounds::AllocFull>>();
capptr::Alloc<void>(small_alloc_one(MIN_ALLOC_SIZE))
.template as_static<FreeObject::T<capptr::bounds::Alloc>>();
if (dummy == nullptr)
{
error("Critical error: Out-of-memory during initialisation.");
@@ -185,8 +185,9 @@ namespace snmalloc
size,
[&](
sizeclass_t sizeclass,
FreeListIter<capptr::bounds::AllocFull, capptr::bounds::AllocFull>*
fl) { return small_alloc<NoZero>(sizeclass, *fl); });
FreeListIter<capptr::bounds::Alloc, capptr::bounds::Alloc>* fl) {
return small_alloc<NoZero>(sizeclass, *fl);
});
}
static SNMALLOC_FAST_PATH void alloc_new_list(
@@ -248,7 +249,8 @@ namespace snmalloc
do
{
b.add(
FreeObject::make<capptr::bounds::AllocFull>(curr_ptr.as_void()),
FreeObject::make<capptr::bounds::Alloc>(
capptr_to_user_address_control(curr_ptr.as_void())),
key,
entropy);
curr_ptr = curr_ptr->next;
@@ -258,9 +260,10 @@ namespace snmalloc
do
{
b.add(
Aal::capptr_bound<
FreeObject::T<capptr::bounds::AllocFull>,
capptr::bounds::AllocFull>(p, rsize),
FreeObject::make<capptr::bounds::Alloc>(
capptr_to_user_address_control(
Aal::capptr_bound<void, capptr::bounds::AllocFull>(
p.as_void(), rsize))),
key);
p = pointer_offset(p, rsize);
} while (p < slab_end);
@@ -272,7 +275,7 @@ namespace snmalloc
ChunkRecord* clear_slab(Metaslab* meta, sizeclass_t sizeclass)
{
auto& key = entropy.get_free_list_key();
FreeListIter<capptr::bounds::AllocFull, capptr::bounds::AllocFull> fl;
FreeListIter<capptr::bounds::Alloc, capptr::bounds::Alloc> fl;
auto more = meta->free_queue.close(fl, key);
UNUSED(more);
void* p = finish_alloc_no_zero(fl.take(key), sizeclass);
@@ -435,7 +438,7 @@ namespace snmalloc
*/
void handle_dealloc_remote(
const MetaEntry& entry,
CapPtr<void, capptr::bounds::AllocFull> p,
CapPtr<void, capptr::bounds::Alloc> p,
bool& need_post)
{
// TODO this needs to not double count stats
@@ -444,7 +447,7 @@ namespace snmalloc
if (likely(entry.get_remote() == public_state()))
{
if (likely(dealloc_local_object_fast(entry, p.unsafe_ptr(), entropy)))
if (likely(dealloc_local_object_fast(entry, p.as_void(), entropy)))
return;
dealloc_local_object_slow(entry);
@@ -569,7 +572,8 @@ namespace snmalloc
return handle_message_queue_inner(action, args...);
}
SNMALLOC_FAST_PATH void dealloc_local_object(void* p)
SNMALLOC_FAST_PATH void
dealloc_local_object(CapPtr<void, capptr::bounds::Alloc> p)
{
auto entry = SharedStateHandle::Pagemap::get_metaentry(
backend_state_ptr(), snmalloc::address_cast(p));
@@ -580,7 +584,9 @@ namespace snmalloc
}
SNMALLOC_FAST_PATH static bool dealloc_local_object_fast(
const MetaEntry& entry, void* p, LocalEntropy& entropy)
const MetaEntry& entry,
CapPtr<void, capptr::bounds::Alloc> p,
LocalEntropy& entropy)
{
auto meta = entry.get_metaslab();
@@ -590,8 +596,7 @@ namespace snmalloc
Metaslab::is_start_of_object(entry.get_sizeclass(), address_cast(p)),
"Not deallocating start of an object");
auto cp = FreeObject::QueuePtr<capptr::bounds::AllocFull>(
reinterpret_cast<FreeObject::T<capptr::bounds::AllocFull>*>(p));
auto cp = p.as_static<FreeObject::T<capptr::bounds::Alloc>>();
auto& key = entropy.get_free_list_key();
@@ -604,7 +609,7 @@ namespace snmalloc
template<ZeroMem zero_mem>
SNMALLOC_SLOW_PATH void* small_alloc(
sizeclass_t sizeclass,
FreeListIter<capptr::bounds::AllocFull, capptr::bounds::AllocFull>&
FreeListIter<capptr::bounds::Alloc, capptr::bounds::Alloc>&
fast_free_list)
{
size_t rsize = sizeclass_to_size(sizeclass);
@@ -664,7 +669,7 @@ namespace snmalloc
template<ZeroMem zero_mem>
SNMALLOC_SLOW_PATH void* small_alloc_slow(
sizeclass_t sizeclass,
FreeListIter<capptr::bounds::AllocFull, capptr::bounds::AllocFull>&
FreeListIter<capptr::bounds::Alloc, capptr::bounds::Alloc>&
fast_free_list,
size_t rsize)
{
@@ -717,7 +722,7 @@ namespace snmalloc
{
SNMALLOC_ASSERT(attached_cache != nullptr);
// TODO: Placeholder
auto domesticate = [](FreeObject::QueuePtr<capptr::bounds::AllocFull> p)
auto domesticate = [](FreeObject::QueuePtr<capptr::bounds::Alloc> p)
SNMALLOC_FAST_PATH_LAMBDA { return p; };
if (destroy_queue)