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Bug 1735482 - Don't use a QuantumWide size class on MacOS r=glandium 

Differential Revision: https://phabricator.services.mozilla.com/D131576
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Paul Bone 2021-11-23 02:01:59 +00:00
Родитель 57c58ccb99
Коммит 9a5f36b0dd
1 изменённых файлов: 64 добавлений и 52 удалений
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116
memory/build/mozjemalloc.cpp
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@ -55,54 +55,57 @@
// categories according to size class. Assuming runtime defaults, the size
// classes in each category are as follows (for x86, x86_64 and Apple Silicon):
//
// |===============================================================|
// | Category | Subcategory | x86 | x86_64 | Apple Silicon |
// |---------------------------+---------+---------+---------------+
// | Word size | 32 bit | 64 bit | 64 bit |
// | Page size | 4 Kb | 4 Kb | 16 Kb |
// |===============================================================|
// | Small | Tiny | 4/- | - | - |
// | | | 8 | 8/- | 8 |
// | |----------------+---------|---------|---------------|
// | | Quantum-spaced | 16 | 16 | 16 |
// | | | 32 | 32 | 32 |
// | | | 48 | 48 | 48 |
// | | | ... | ... | ... |
// | | | 480 | 480 | 480 |
// | | | 496 | 496 | 496 |
// | |----------------+---------|---------|---------------|
// | | Quantum-wide- | 512 | 512 | 512 |
// | | spaced | 768 | 768 | 768 |
// | | | ... | ... | ... |
// | | | 3584 | 3584 | 3584 |
// | | | 3840 | 3840 | 3840 |
// | |----------------+---------|---------|---------------|
// | | Sub-page | - | - | 4096 |
// | | | - | - | 8 kB |
// |===============================================================|
// | Large | 4 kB | 4 kB | - |
// | | 8 kB | 8 kB | - |
// | | 12 kB | 12 kB | - |
// | | 16 kB | 16 kB | 16 kB |
// | | ... | ... | - |
// | | 32 kB | 32 kB | 32 kB |
// | | ... | ... | ... |
// | | 1008 kB | 1008 kB | 1008 kB |
// | | 1012 kB | 1012 kB | - |
// | | 1016 kB | 1012 kB | - |
// | | 1020 kB | 1020 kB | - |
// |===============================================================|
// | Huge | 1 MB | 1 MB | 1 MB |
// | | 2 MB | 2 MB | 2 MB |
// | | 3 MB | 3 MB | 3 MB |
// | | ... | ... | ... |
// |===============================================================|
// |======================================================================|
// | Category | Subcategory | x86 | x86_64 | Mac x86_64 | Mac ARM |
// |---------------------------+---------+---------+------------+---------|
// | Word size | 32 bit | 64 bit | 64 bit | 64 bit |
// | Page size | 4 Kb | 4 Kb | 4 Kb | 16 Kb |
// |======================================================================|
// | Small | Tiny | 4/-w | -w | - | - |
// | | | 8 | 8/-w | 8 | 8 |
// | |----------------+---------|---------|------------|---------|
// | | Quantum-spaced | 16 | 16 | 16 | 16 |
// | | | 32 | 32 | 32 | 32 |
// | | | 48 | 48 | 48 | 48 |
// | | | ... | ... | ... | ... |
// | | | 480 | 480 | 480 | 480 |
// | | | 496 | 496 | 496 | 496 |
// | |----------------+---------|---------|------------|---------|
// | | Quantum-wide- | 512 | 512 | - | - |
// | | spaced | 768 | 768 | - | - |
// | | | ... | ... | - | - |
// | | | 3584 | 3584 | - | - |
// | | | 3840 | 3840 | - | - |
// | |----------------+---------|---------|------------|---------|
// | | Sub-page | - | - | 512 | 512 |
// | | | - | - | 1024 | 1024 |
// | | | - | - | 2048 | 2048 |
// | | | - | - | | 4096 |
// | | | - | - | | 8 kB |
// |============================================================|=========|
// | Large | 4 kB | 4 kB | 4 kB | - |
// | | 8 kB | 8 kB | 8 kB | - |
// | | 12 kB | 12 kB | 12 kB | - |
// | | 16 kB | 16 kB | 16 kB | 16 kB |
// | | ... | ... | ... | - |
// | | 32 kB | 32 kB | 32 kB | 32 kB |
// | | ... | ... | ... | ... |
// | | 1008 kB | 1008 kB | 1008 kB | 1008 kB |
// | | 1012 kB | 1012 kB | 1012 kB | - |
// | | 1016 kB | 1016 kB | 1016 kB | - |
// | | 1020 kB | 1020 kB | 1020 kB | - |
// |======================================================================|
// | Huge | 1 MB | 1 MB | 1 MB | 1 MB |
// | | 2 MB | 2 MB | 2 MB | 2 MB |
// | | 3 MB | 3 MB | 3 MB | 3 MB |
// | | ... | ... | ... | ... |
// |======================================================================|
//
// Legend:
// n: Size class exists for this platform.
// n/-: This size class doesn't exist on Windows (see kMinTinyClass).
// -: This size class doesn't exist for this platform.
// ...: Size classes follow a pattern here.
// n: Size class exists for this platform.
// n/-w: This size class doesn't exist on Windows (see kMinTinyClass).
// -: This size class doesn't exist for this platform.
// ...: Size classes follow a pattern here.
//
// NOTE: Due to Mozilla bug 691003, we cannot reserve less than one word for an
// allocation on Linux or Mac. So on 32-bit *nix, the smallest bucket size is
@ -416,7 +419,11 @@ static const size_t kMaxTinyClass = 8;
// them.
static const size_t kMinQuantumClass = kMaxTinyClass * 2;
static const size_t kMinQuantumWideClass = 512;
#ifdef XP_MACOSX
static const size_t kMinSubPageClass = 512;
#else
static const size_t kMinSubPageClass = 4_KiB;
#endif
// Amount (quantum) separating quantum-spaced size classes.
static const size_t kQuantum = 16;
@ -446,11 +453,12 @@ static_assert(mozilla::IsPowerOfTwo(kMinSubPageClass),
static const size_t kNumTinyClasses =
LOG2(kMaxTinyClass) - LOG2(kMinTinyClass) + 1;
// Number of quantum-spaced classes.
// Number of quantum-spaced classes. We add kQuantum(Max) before subtracting to
// avoid underflow when a class is empty (Max<Min).
static const size_t kNumQuantumClasses =
(kMaxQuantumClass - kMinQuantumClass) / kQuantum + 1;
(kMaxQuantumClass + kQuantum - kMinQuantumClass) / kQuantum;
static const size_t kNumQuantumWideClasses =
(kMaxQuantumWideClass - kMinQuantumWideClass) / kQuantumWide + 1;
(kMaxQuantumWideClass + kQuantumWide - kMinQuantumWideClass) / kQuantumWide;
// Size and alignment of memory chunks that are allocated by the OS's virtual
// memory system.
@ -551,7 +559,8 @@ GLOBAL_ASSERT(1ULL << gPageSize2Pow == gPageSize,
"Page size is not a power of two");
GLOBAL_ASSERT(kQuantum >= sizeof(void*));
GLOBAL_ASSERT(kQuantum <= kQuantumWide);
GLOBAL_ASSERT(kQuantumWide <= (kMinSubPageClass - kMaxQuantumClass));
GLOBAL_ASSERT(!kNumQuantumWideClasses ||
kQuantumWide <= (kMinSubPageClass - kMaxQuantumClass));
GLOBAL_ASSERT(kQuantumWide <= kMaxQuantumClass);
@ -2253,7 +2262,6 @@ struct FastDivide {
mozilla::IsPowerOfTwo(Max) ? Max - Q : Max;
// +1 because this range is inclusive.
static const unsigned num_divisors = (max_divisor - min_divisor) / Q + 1;
static_assert(max_divisor > min_divisor);
static const unsigned inv_shift = 21;
@ -2274,7 +2282,11 @@ struct FastDivide {
inv(28), inv(29), inv(30), inv(31)
};
// clang-format on
static_assert(num_divisors <= sizeof(size_invs) / sizeof(unsigned),
// If the divisor is valid (min is below max) then the size_invs array must
// be large enough.
static_assert(!(min_divisor < max_divisor) ||
num_divisors <= sizeof(size_invs) / sizeof(unsigned),
"num_divisors does not match array size");
MOZ_ASSERT(div >= min_divisor);