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handle_dealloc_remote: restructure to avoid amplification when routing

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When forwarding a Remote message, we can now operate entirely with local state:
access to our RemoteCache and the message itself.
This commit is contained in:
Nathaniel Filardo
2020-12-14 18:48:43 +00:00
committed by Matthew Parkinson
parent bf742cef84
commit 975a2bd6db
1 changed files with 15 additions and 26 deletions
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41
src/mem/alloc.h
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@@ -867,44 +867,33 @@ namespace snmalloc
SNMALLOC_FAST_PATH void handle_dealloc_remote(Remote* p)
{
Superslab* super = Superslab::get(p);
if (likely(p->trunc_target_id() == get_trunc_id()))
{
// Destined for my slabs
Superslab* super = Superslab::get(p);
#ifdef CHECK_CLIENT
if (p->trunc_target_id() != (super->get_allocator()->trunc_id()))
error("Detected memory corruption. Potential use-after-free");
if (p->trunc_target_id() != (super->get_allocator()->trunc_id()))
error("Detected memory corruption. Potential use-after-free");
#endif
if (likely(super->get_kind() == Super))
{
if (likely(super->get_allocator() == public_state()))
{
small_dealloc_offseted(super, p, p->sizeclass());
return;
}
}
handle_dealloc_remote_slow(p);
}
// Guard against remote queues that have colliding IDs
SNMALLOC_ASSERT(super->get_allocator() == public_state());
SNMALLOC_SLOW_PATH void handle_dealloc_remote_slow(Remote* p)
{
Superslab* super = Superslab::get(p);
if (likely(super->get_kind() == Medium))
{
if (likely(super->get_allocator() == public_state()))
if (likely(p->sizeclass() < NUM_SMALL_CLASSES))
{
void* start = remove_cache_friendly_offset(p, p->sizeclass());
medium_dealloc(Mediumslab::get(p), start, p->sizeclass());
SNMALLOC_ASSERT(super->get_kind() == Super);
small_dealloc_offseted(super, p, p->sizeclass());
}
else
{
// Queue for remote dealloc elsewhere.
remote.dealloc(p->trunc_target_id(), p, p->sizeclass());
SNMALLOC_ASSERT(super->get_kind() == Medium);
void* start = remove_cache_friendly_offset(p, p->sizeclass());
medium_dealloc(Mediumslab::get(p), start, p->sizeclass());
}
}
else
{
SNMALLOC_ASSERT(likely(p->trunc_target_id() != get_trunc_id()));
SNMALLOC_ASSERT(likely(super->get_allocator() != public_state()));
// Queue for remote dealloc elsewhere.
// Merely routing
remote.dealloc(p->trunc_target_id(), p, p->sizeclass());
}
}