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mm: make physical allocation blocking (WIP)

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Loïc Grégoire
2026-06-29 22:33:43 -04:00
parent 11c858c5e8
commit 85e6a8fec9
11 changed files with 160 additions and 72 deletions
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src/mm/zone.zig
+29 -33
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@@ -258,7 +258,7 @@ pub const Zone = struct {
/// Current color for slab coloring.
color: usize,
/// Zone lock.
lock: ke.QSpinLock,
lock: ke.Mutex,
/// List of full slabs in this zone.
full_slabs: rtl.List,
/// List of partial slabs in this zone.
@@ -344,9 +344,7 @@ pub const Zone = struct {
}
/// Allocate an object from the zone.
pub fn alloc(self: *Self) mm.Error!*anyopaque {
const ipl = ke.ipl.raise(.Dispatch);
defer ke.ipl.lower(ipl);
pub fn alloc(self: *Self, opts: struct { policy: mm.WaitPolicy = .WaitForMemory }) mm.Error!*anyopaque {
var buf: *anyopaque = undefined;
// Try grabbing an object from the magazine layer.
@@ -354,8 +352,8 @@ pub const Zone = struct {
@branchHint(.likely);
const cpu = &self.cpus[ke.cpu.current()];
cpu.lock.acquire_no_ipl();
defer cpu.lock.release_no_ipl();
const ipl = cpu.lock.acquire();
defer cpu.lock.release(ipl);
while (true) {
if (cpu.alloc_rounds > 0) {
@@ -407,13 +405,17 @@ pub const Zone = struct {
}
// Fall back to the slab layer.
self.lock.acquire_no_ipl();
defer self.lock.release_no_ipl();
self.lock.acquire();
defer self.lock.release();
var slab: *Slab = undefined;
if (self.partial_slabs.is_empty()) {
slab = try self.slab_create();
self.lock.release();
slab = try self.slab_create(opts.policy);
self.lock.acquire();
self.partial_slabs.insert_tail(&slab.link);
} else {
slab = @fieldParentPtr("link", self.partial_slabs.first());
@@ -446,16 +448,14 @@ pub const Zone = struct {
/// Free an object back to the zone.
pub fn free(self: *Self, obj: *anyopaque) void {
const ipl = ke.ipl.raise(.Dispatch);
defer ke.ipl.lower(ipl);
if (magazines_initialized and self.use_magazines) {
@branchHint(.likely);
const cpu = &self.cpus[ke.cpu.current()];
const ipl = ke.ipl.raise(.Dispatch);
var cpu = &self.cpus[ke.cpu.current()];
cpu.lock.acquire_no_ipl();
defer cpu.lock.release_no_ipl();
defer cpu.lock.release(ipl);
while (true) {
if (cpu.free != null and cpu.free_rounds < cpu.magazine_size) {
@@ -495,11 +495,7 @@ pub const Zone = struct {
}
// No empty magazine in the depot, try to allocate a new one.
cpu.lock.release_no_ipl();
const new_mag: ?*Magazine = @ptrCast(@alignCast(self.magtype.?.zone.alloc() catch null));
cpu.lock.acquire_no_ipl();
const new_mag: ?*Magazine = @ptrCast(@alignCast(self.magtype.?.zone.alloc(.{ .policy = .DontWaitForMemory }) catch null));
if (new_mag) |m| {
self.free_to_depot(m, &self.empty_mags);
@@ -518,8 +514,8 @@ pub const Zone = struct {
fill_with_poison(obj, self.obj_size, free_poison);
}
self.lock.acquire_no_ipl();
defer self.lock.release_no_ipl();
self.lock.acquire();
defer self.lock.release();
// Find the slab for the buffer.
const slab: *Slab = if (self.obj_size > small_slab_size) blk: {
@@ -551,8 +547,8 @@ pub const Zone = struct {
}
}
fn alloc_page() !*anyopaque {
const alloc_ret = mi.phys.alloc();
fn alloc_page(policy: mm.WaitPolicy) !*anyopaque {
const alloc_ret = mi.phys.alloc_opts(.{ .policy = policy }) orelse return error.OutOfMemory;
return @ptrFromInt(mm.p2v(alloc_ret));
}
@@ -562,8 +558,8 @@ pub const Zone = struct {
mi.phys.free(phys);
}
fn slab_create_small(self: *Self) mm.Error!*Slab {
const buf = try alloc_page();
fn slab_create_small(self: *Self, policy: mm.WaitPolicy) mm.Error!*Slab {
const buf = try alloc_page(policy);
// We employ a simple coloring scheme; every time a slab is created,
// the color is shifted by the alignment. This is done until we reach the
@@ -604,7 +600,7 @@ pub const Zone = struct {
return slab;
}
fn slab_create_large(self: *Self) mm.Error!*Slab {
fn slab_create_large(self: *Self, policy: mm.WaitPolicy) mm.Error!*Slab {
self.color += self.alignment;
if (self.color > self.max_color) {
@@ -612,7 +608,7 @@ pub const Zone = struct {
}
const capacity = (self.slab_size - self.color) / self.chunk_size;
const buf = try mi.heap.alloc(self.slab_size);
const buf = try mi.heap.alloc(self.slab_size, policy);
var ret: *Slab = @ptrCast(@alignCast(try gpa.alloc(u8, @sizeOf(Slab) + Slab.bitmap_bytes(capacity))));
@@ -648,11 +644,11 @@ pub const Zone = struct {
return ret;
}
fn slab_create(self: *Self) mm.Error!*Slab {
fn slab_create(self: *Self, policy: mm.WaitPolicy) mm.Error!*Slab {
if (self.obj_size <= small_slab_size) {
return self.slab_create_small();
return self.slab_create_small(policy);
} else {
return self.slab_create_large();
return self.slab_create_large(policy);
}
}
@@ -723,7 +719,7 @@ pub fn TypedZone(comptime T: type) type {
}
pub fn create(self: *Self) mm.Error!*T {
const ret = try self.zone.alloc();
const ret = try self.zone.alloc(.{});
return @ptrCast(@alignCast(ret));
}
@@ -794,12 +790,12 @@ fn gpa_alloc(
if (len > 2048) {
if (ptr_align.toByteUnits() > mm.page_size) return null;
const pages = std.mem.alignForward(usize, len, mm.page_size);
const ptr = mi.heap.alloc(pages) catch return null;
const ptr = mi.heap.alloc(pages, .WaitForMemory) catch return null;
return @ptrCast(ptr);
}
const zone = zone_for(len, ptr_align.toByteUnits()) orelse return null;
const obj = zone.alloc() catch return null;
const obj = zone.alloc(.{}) catch return null;
return @ptrCast(obj);
}