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restructure the page flags to use explicit masks

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This commit is contained in:
daan 2019-08-10 17:48:00 -07:00
parent c0258b2d29
commit ed785253bf
6 changed files with 53 additions and 45 deletions
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29
include/mimalloc-internal.h
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@ -314,16 +314,37 @@ static inline mi_page_queue_t* mi_page_queue(const mi_heap_t* heap, size_t size)
return &((mi_heap_t*)heap)->pages[_mi_bin(size)];
}
//-----------------------------------------------------------
// Page flags
//-----------------------------------------------------------
static inline uintptr_t mi_page_thread_id(const mi_page_t* page) {
return (page->flags.xthread_id << MI_PAGE_FLAGS_BITS);
return (page->flags & ~MI_PAGE_FLAGS_MASK);
}
static inline void mi_page_init_flags(mi_page_t* page, uintptr_t thread_id) {
page->flags.value = 0;
page->flags.xthread_id = (thread_id >> MI_PAGE_FLAGS_BITS);
mi_assert(page->flags.value == thread_id);
page->flags = thread_id;
}
static inline bool mi_page_is_in_full(const mi_page_t* page) {
return ((page->flags & 0x01) != 0);
}
static inline void mi_page_set_in_full(mi_page_t* page, bool in_full) {
if (in_full) page->flags |= 0x01;
else page->flags &= ~0x01;
}
static inline bool mi_page_has_aligned(const mi_page_t* page) {
return ((page->flags & 0x02) != 0);
}
static inline void mi_page_set_has_aligned(mi_page_t* page, bool has_aligned) {
if (has_aligned) page->flags |= 0x02;
else page->flags &= ~0x02;
}
// -------------------------------------------------------------------
// Encoding/Decoding the free list next pointers
// -------------------------------------------------------------------

21
include/mimalloc-types.h
View file

@ -123,25 +123,12 @@ typedef enum mi_delayed_e {
} mi_delayed_t;
// Use the lowest two bits of a thread id for the `in_full` and `has_aligned` flags
// Use the bottom 2 bits for the `in_full` and `has_aligned` flags
// and the rest for the threadid (we assume tid's never use those lower 2 bits).
// This allows a single test in `mi_free` to check for unlikely cases
// (namely, non-local free, aligned free, or freeing in a full page)
#define MI_PAGE_FLAGS_BITS (2)
#define MI_PAGE_FLAGS_TID_BITS (MI_INTPTR_SIZE*8 - MI_PAGE_FLAGS_BITS)
typedef union mi_page_flags_u {
uintptr_t value;
struct {
#ifdef MI_BIG_ENDIAN
uintptr_t xthread_id : MI_PAGE_FLAGS_TID_BITS;
#endif
uintptr_t in_full : 1;
uintptr_t has_aligned : 1;
#ifndef MI_BIG_ENDIAN
uintptr_t xthread_id : MI_PAGE_FLAGS_TID_BITS;
#endif
};
} mi_page_flags_t;
#define MI_PAGE_FLAGS_MASK ((uintptr_t)0x03)
typedef uintptr_t mi_page_flags_t;
// Thread free list.
// We use the bottom 2 bits of the pointer for mi_delayed_t flags