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Date: Tue, 24 Oct 2017 14:08:01 -0400
From: Prarit Bhargava <prarit@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: Andi Kleen <ak@...ux.intel.com>,
Prarit Bhargava <prarit@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>,
"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
Peter Zijlstra <peterz@...radead.org>,
Dave Hansen <dave.hansen@...el.com>,
Piotr Luc <piotr.luc@...el.com>,
Kan Liang <kan.liang@...el.com>, Borislav Petkov <bp@...e.de>,
Stephane Eranian <eranian@...gle.com>,
Arvind Yadav <arvind.yadav.cs@...il.com>,
Andy Lutomirski <luto@...nel.org>,
Christian Borntraeger <borntraeger@...ibm.com>,
"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Tom Lendacky <thomas.lendacky@....com>,
Mathias Krause <minipli@...glemail.com>,
Tim Chen <tim.c.chen@...ux.intel.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>
Subject: [PATCH 2/3] x86/topology: Avoid wasting 128k for package id array
From: Andi Kleen <ak@...ux.intel.com>
I was looking at large early boot allocations and noticed that since
(1f12e32f x86/topology: Create logical package id) every 64bit system
allocates a 128k array to convert logical package ids.
This happens because the array is sized to (MAX_LOCAL_APIC * u16) = 128k.
This is a lot of waste especially for most systems which have one or two
sockets.
Use a dynamically allocated array of size logical_packages to map
the logical and physical packages.
[v2]: Decrease logical_packages when the last thread in a socket is
removed.
[v3]: Add more logic to keep logical and physical package IDs
in synch.
[v4]: Keep logical mapping static by using hybrid approach of a small logical
to physical array and keeping logical cpu information in cpu_data.
Signed-off-by: Andi Kleen <ak@...ux.intel.com>
Signed-off-by: Prarit Bhargava <prarit@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: x86@...nel.org
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Andi Kleen <ak@...ux.intel.com>
Cc: Dave Hansen <dave.hansen@...el.com>
Cc: Piotr Luc <piotr.luc@...el.com>
Cc: Kan Liang <kan.liang@...el.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Prarit Bhargava <prarit@...hat.com>
Cc: Arvind Yadav <arvind.yadav.cs@...il.com>
Cc: Andy Lutomirski <luto@...nel.org>
Cc: Christian Borntraeger <borntraeger@...ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Tom Lendacky <thomas.lendacky@....com>
Cc: Mathias Krause <minipli@...glemail.com>
Cc: Tim Chen <tim.c.chen@...ux.intel.com>
Cc: Vitaly Kuznetsov <vkuznets@...hat.com>
---
arch/x86/include/asm/processor.h | 4 +-
arch/x86/kernel/smpboot.c | 86 +++++++++++++++++++---------------------
2 files changed, 43 insertions(+), 47 deletions(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b390ff76e58f..f4ab1edf4e24 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -124,8 +124,10 @@ struct cpuinfo_x86 {
u16 booted_cores;
/* Physical processor id: */
u16 phys_proc_id;
- /* Logical processor id: */
+ /* Logical processor (package) id: */
u16 logical_proc_id;
+ /* Physical package ID */
+ u16 phys_pkg_id;
/* Core id: */
u16 cpu_core_id;
/* Index into per_cpu list: */
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index ad59edd84de7..ca615bc94e82 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -99,12 +99,10 @@ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
EXPORT_PER_CPU_SYMBOL(cpu_info);
-/* Logical package management. We might want to allocate that dynamically */
-static int *physical_to_logical_pkg __read_mostly;
-static unsigned long *physical_package_map __read_mostly;;
-static unsigned int max_physical_pkg_id __read_mostly;
+/* Logical package management.*/
unsigned int __max_logical_packages __read_mostly;
EXPORT_SYMBOL(__max_logical_packages);
+static u16 *logical_to_physical_pkg_map;
static unsigned int logical_packages __read_mostly;
/* Maximum number of SMT threads on any online core */
@@ -278,6 +276,23 @@ static void notrace start_secondary(void *unused)
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}
+/**
+ * topology_phys_to_logical_pkg - Map a physical package id to a logical
+ *
+ * Returns logical package id or -1 if not found
+ */
+int topology_phys_to_logical_pkg(unsigned int phys_pkg)
+{
+ int log_pkg;
+
+ for (log_pkg = 0; log_pkg < logical_packages; log_pkg++)
+ if (logical_to_physical_pkg_map[log_pkg] == phys_pkg)
+ return log_pkg;
+
+ return -1;
+}
+EXPORT_SYMBOL(topology_phys_to_logical_pkg);
+
/**
* topology_update_package_map - Update the physical to logical package map
* @pkg: The physical package id as retrieved via CPUID
@@ -285,17 +300,11 @@ static void notrace start_secondary(void *unused)
*/
int topology_update_package_map(unsigned int pkg, unsigned int cpu)
{
- unsigned int new;
-
- /* Called from early boot ? */
- if (!physical_package_map)
- return 0;
-
- if (pkg >= max_physical_pkg_id)
- return -EINVAL;
+ int new;
+ u16 *ltp_pkg_map_new;
- /* Set the logical package id */
- if (test_and_set_bit(pkg, physical_package_map))
+ new = topology_phys_to_logical_pkg(pkg);
+ if (new >= 0)
goto found;
if (logical_packages >= __max_logical_packages) {
@@ -305,34 +314,30 @@ int topology_update_package_map(unsigned int pkg, unsigned int cpu)
}
new = logical_packages++;
- if (new != pkg) {
- pr_info("CPU %u Converting physical %u to logical package %u\n",
- cpu, pkg, new);
+
+ /* Allocate and copy a new array */
+ ltp_pkg_map_new = kmalloc(logical_packages * sizeof(u16), GFP_KERNEL);
+ BUG_ON(!ltp_pkg_map_new);
+ if (logical_to_physical_pkg_map) {
+ memcpy(ltp_pkg_map_new, logical_to_physical_pkg_map,
+ logical_packages * sizeof(u16));
+ kfree(logical_to_physical_pkg_map);
}
- physical_to_logical_pkg[pkg] = new;
+ logical_to_physical_pkg_map = ltp_pkg_map_new;
+ logical_to_physical_pkg_map[new] = pkg;
+ if (pkg != new)
+ pr_info("CPU %u Converting physical %u to logical package %u\n",
+ cpu, pkg, new);
found:
- cpu_data(cpu).logical_proc_id = physical_to_logical_pkg[pkg];
+ cpu_data(cpu).phys_pkg_id = pkg;
+ cpu_data(cpu).logical_proc_id = new;
return 0;
}
-/**
- * topology_phys_to_logical_pkg - Map a physical package id to a logical
- *
- * Returns logical package id or -1 if not found
- */
-int topology_phys_to_logical_pkg(unsigned int phys_pkg)
-{
- if (phys_pkg >= max_physical_pkg_id)
- return -1;
- return physical_to_logical_pkg[phys_pkg];
-}
-EXPORT_SYMBOL(topology_phys_to_logical_pkg);
-
static void __init smp_init_package_map(struct cpuinfo_x86 *c, unsigned int cpu)
{
unsigned int ncpus;
- size_t size;
/*
* Today neither Intel nor AMD support heterogenous systems. That
@@ -363,21 +368,10 @@ static void __init smp_init_package_map(struct cpuinfo_x86 *c, unsigned int cpu)
}
__max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus);
- logical_packages = 0;
-
- /*
- * Possibly larger than what we need as the number of apic ids per
- * package can be smaller than the actual used apic ids.
- */
- max_physical_pkg_id = DIV_ROUND_UP(MAX_LOCAL_APIC, ncpus);
- size = max_physical_pkg_id * sizeof(unsigned int);
- physical_to_logical_pkg = kmalloc(size, GFP_KERNEL);
- memset(physical_to_logical_pkg, 0xff, size);
- size = BITS_TO_LONGS(max_physical_pkg_id) * sizeof(unsigned long);
- physical_package_map = kzalloc(size, GFP_KERNEL);
-
pr_info("Max logical packages: %u\n", __max_logical_packages);
+ logical_packages = 0;
+
topology_update_package_map(c->phys_proc_id, cpu);
}
--
2.15.0.rc0.39.g2f0e14e64
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