File fix-aarch64.patch of Package scx

From ced285a14129da72b44c4170e5fa2bb9be510c76 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fredrik=20L=C3=B6nnegren?= <fredrik@frelon.se>
Date: Thu, 13 Feb 2025 08:06:25 -0800
Subject: [PATCH] backport upstream fixes for aarch64

Backport and squash the following commits:

  * 4997c240986cba2b4b5bcb1ebe0ebed56f105ac3
  * 3bc716a46a93193f993cd9ab5465856be814392e
  * 7f992e30893199479d4878922e81c48a94c8fbb3
  * 406031b6a95ce95ec61d77ade4d9ee43d284b01f
  * a59e0ae4a1430271b0b67f9cd58e0aafaf6e820e
---
 lib/sdt_alloc.bpf.c                      |  7 ++++---
 scheds/rust/scx_rusty/src/bpf/main.bpf.c | 25 ++++++++++++++++++------
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/lib/sdt_alloc.bpf.c b/lib/sdt_alloc.bpf.c
index 418e63da..4f6c4010 100644
--- a/lib/sdt_alloc.bpf.c
+++ b/lib/sdt_alloc.bpf.c
@@ -13,10 +13,11 @@ char _license[] SEC("license") = "GPL";
 struct {
 	__uint(type, BPF_MAP_TYPE_ARENA);
 	__uint(map_flags, BPF_F_MMAPABLE);
-	__uint(max_entries, 1 << 20); /* number of pages */
 #ifdef __TARGET_ARCH_arm64
+	__uint(max_entries, 1 << 16); /* number of pages */
         __ulong(map_extra, (1ull << 32)); /* start of mmap() region */
 #else
+	__uint(max_entries, 1 << 20); /* number of pages */
         __ulong(map_extra, (1ull << 44)); /* start of mmap() region */
 #endif
 } arena __weak SEC(".maps");
@@ -307,8 +308,8 @@ sdt_alloc_init(struct sdt_allocator *alloc, __u64 data_size)
 	size_t min_chunk_size;
 	int ret;
 
-	_Static_assert(sizeof(struct sdt_chunk)  == PAGE_SIZE,
-		"chunk size must be equal to a page");
+	_Static_assert(sizeof(struct sdt_chunk) <= PAGE_SIZE,
+		"chunk size must fit into a page");
 
 	ret = sdt_pool_set_size(&sdt_chunk_pool, sizeof(struct sdt_chunk), 1);
 	if (ret != 0)
diff --git a/scheds/rust/scx_rusty/src/bpf/main.bpf.c b/scheds/rust/scx_rusty/src/bpf/main.bpf.c
index 598cfcef..74a57f8c 100644
--- a/scheds/rust/scx_rusty/src/bpf/main.bpf.c
+++ b/scheds/rust/scx_rusty/src/bpf/main.bpf.c
@@ -1279,6 +1279,7 @@ static u64 node_dom_mask(u32 node_id)
 	return mask;
 }
 
+#ifndef __TARGET_ARCH_arm64
 /*
  * Sets the preferred domain mask according to the mempolicy. See man(2)
  * set_mempolicy for more details on mempolicy.
@@ -1287,32 +1288,36 @@ static void task_set_preferred_mempolicy_dom_mask(struct task_struct *p,
 						  struct task_ctx *taskc)
 {
 	struct bpf_cpumask *p_cpumask;
+	struct mempolicy *mempolicy;
 	u32 node_id;
 	u32 val = 0;
 	void *mask;
 
 	taskc->preferred_dom_mask = 0;
 
+	mempolicy = BPF_CORE_READ(p, mempolicy);
+	if (!mempolicy)
+		return;
+
 	p_cpumask = lookup_task_bpfmask(p);
 
-	if (!mempolicy_affinity || !bpf_core_field_exists(p->mempolicy) ||
-	    !p->mempolicy || !p_cpumask)
+	if (!mempolicy_affinity || !p_cpumask)
 		return;
 
-	if (!(p->mempolicy->mode & (MPOL_BIND|MPOL_PREFERRED|MPOL_PREFERRED_MANY)))
+	if (!(mempolicy->mode & (MPOL_BIND|MPOL_PREFERRED|MPOL_PREFERRED_MANY)))
 		return;
 
 	// MPOL_BIND and MPOL_PREFERRED_MANY use the home_node field on the
 	// mempolicy struct, so use that for now. In the future the memory
 	// usage of the node can be checked to follow the same algorithm for
 	// where memory allocations will occur.
-	if ((int)p->mempolicy->home_node >= 0) {
+	if ((int)mempolicy->home_node >= 0) {
 		taskc->preferred_dom_mask =
-			node_dom_mask((u32)p->mempolicy->home_node);
+			node_dom_mask((u32)mempolicy->home_node);
 		return;
 	}
 
-	mask = BPF_CORE_READ(p, mempolicy, nodes.bits);
+	mask = BPF_CORE_READ(mempolicy, nodes.bits);
 	if (bpf_core_read(&val, sizeof(val), mask))
 		return;
 
@@ -1325,6 +1330,14 @@ static void task_set_preferred_mempolicy_dom_mask(struct task_struct *p,
 
 	return;
 }
+#else
+
+static void task_set_preferred_mempolicy_dom_mask(struct task_struct *p,
+                                                 struct task_ctx *taskc)
+{}
+
+#endif
+
 
 void BPF_STRUCT_OPS(rusty_dispatch, s32 cpu, struct task_struct *prev)
 {
-- 
2.48.1