From: "Ross Biro" <rossb@google.com>
To: Mel Gorman <mel@skynet.ie>
Cc: Dave Hansen <haveblue@us.ibm.com>,
linux-mm@kvack.org, Mel Gorman <MELGOR@ie.ibm.com>
Subject: Re: RFC/POC Make Page Tables Relocatable Part 1 Create Conditional Flush
Date: Fri, 30 Nov 2007 11:35:06 -0500 [thread overview]
Message-ID: <d43160c70711300835i3f4bb3e0n74d6ee4ff2a8167@mail.gmail.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 568 bytes --]
Here's the latest version of my changes to make page tables
relocatable. Currently they work, but they have not been adequately
tested. They are also incomplete because top level page tables cannot
be relocated because they cannot be forced to reload across all cpus.
lmbench shows the overhead of rewalking the page tables is less than
that of spinlock debugging. I'll do real bench marks once everything
is complete. I wanted to send this out now since I'll be on vacation
and I wanted people to have a chance to look at them sooner rather
than later.
Ross
[-- Attachment #2: maybeflush.patch --]
[-- Type: application/octet-stream, Size: 8705 bytes --]
diff -urwNbB 2.6.23/arch/alpha/kernel/smp.c 2.6.23a/arch/alpha/kernel/smp.c
--- 2.6.23/arch/alpha/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/alpha/kernel/smp.c 2007-10-29 13:50:06.000000000 -0700
@@ -850,6 +850,8 @@
{
preempt_disable();
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
if (mm == current->active_mm) {
flush_tlb_current(mm);
if (atomic_read(&mm->mm_users) <= 1) {
diff -urwNbB 2.6.23/arch/arm/kernel/smp.c 2.6.23a/arch/arm/kernel/smp.c
--- 2.6.23/arch/arm/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/arm/kernel/smp.c 2007-10-29 13:50:21.000000000 -0700
@@ -713,6 +713,8 @@
{
cpumask_t mask = mm->cpu_vm_mask;
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
on_each_cpu_mask(ipi_flush_tlb_mm, mm, 1, 1, mask);
}
diff -urwNbB 2.6.23/arch/avr32/mm/tlb.c 2.6.23a/arch/avr32/mm/tlb.c
--- 2.6.23/arch/avr32/mm/tlb.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/avr32/mm/tlb.c 2007-10-29 13:50:39.000000000 -0700
@@ -249,6 +249,8 @@
void flush_tlb_mm(struct mm_struct *mm)
{
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
/* Invalidate all TLB entries of this process by getting a new ASID */
if (mm->context != NO_CONTEXT) {
unsigned long flags;
diff -urwNbB 2.6.23/arch/cris/arch-v10/mm/tlb.c 2.6.23a/arch/cris/arch-v10/mm/tlb.c
--- 2.6.23/arch/cris/arch-v10/mm/tlb.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/cris/arch-v10/mm/tlb.c 2007-10-29 13:50:55.000000000 -0700
@@ -69,6 +69,8 @@
D(printk("tlb: flush mm context %d (%p)\n", page_id, mm));
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
if(page_id == NO_CONTEXT)
return;
diff -urwNbB 2.6.23/arch/cris/arch-v32/kernel/smp.c 2.6.23a/arch/cris/arch-v32/kernel/smp.c
--- 2.6.23/arch/cris/arch-v32/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/cris/arch-v32/kernel/smp.c 2007-10-29 13:51:06.000000000 -0700
@@ -237,6 +237,7 @@
void flush_tlb_mm(struct mm_struct *mm)
{
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
__flush_tlb_mm(mm);
flush_tlb_common(mm, FLUSH_ALL, 0);
/* No more mappings in other CPUs */
diff -urwNbB 2.6.23/arch/i386/kernel/smp.c 2.6.23a/arch/i386/kernel/smp.c
--- 2.6.23/arch/i386/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/i386/kernel/smp.c 2007-10-29 13:51:47.000000000 -0700
@@ -410,6 +410,8 @@
{
cpumask_t cpu_mask;
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
preempt_disable();
cpu_mask = mm->cpu_vm_mask;
cpu_clear(smp_processor_id(), cpu_mask);
diff -urwNbB 2.6.23/arch/i386/mach-voyager/voyager_smp.c 2.6.23a/arch/i386/mach-voyager/voyager_smp.c
--- 2.6.23/arch/i386/mach-voyager/voyager_smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/i386/mach-voyager/voyager_smp.c 2007-10-29 13:51:55.000000000 -0700
@@ -924,6 +924,8 @@
{
unsigned long cpu_mask;
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
preempt_disable();
cpu_mask = cpus_addr(mm->cpu_vm_mask)[0] & ~(1 << smp_processor_id());
diff -urwNbB 2.6.23/arch/ia64/kernel/smp.c 2.6.23a/arch/ia64/kernel/smp.c
--- 2.6.23/arch/ia64/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/ia64/kernel/smp.c 2007-10-29 13:52:03.000000000 -0700
@@ -325,6 +325,8 @@
void
smp_flush_tlb_mm (struct mm_struct *mm)
{
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
preempt_disable();
/* this happens for the common case of a single-threaded fork(): */
if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1))
diff -urwNbB 2.6.23/arch/m32r/kernel/smp.c 2.6.23a/arch/m32r/kernel/smp.c
--- 2.6.23/arch/m32r/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/m32r/kernel/smp.c 2007-10-29 13:52:49.000000000 -0700
@@ -280,6 +280,8 @@
unsigned long *mmc;
unsigned long flags;
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
preempt_disable();
cpu_id = smp_processor_id();
mmc = &mm->context[cpu_id];
diff -urwNbB 2.6.23/arch/mips/kernel/smp.c 2.6.23a/arch/mips/kernel/smp.c
--- 2.6.23/arch/mips/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/mips/kernel/smp.c 2007-10-29 13:53:21.000000000 -0700
@@ -387,6 +387,8 @@
void flush_tlb_mm(struct mm_struct *mm)
{
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
preempt_disable();
if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
diff -urwNbB 2.6.23/arch/powerpc/mm/tlb_32.c 2.6.23a/arch/powerpc/mm/tlb_32.c
--- 2.6.23/arch/powerpc/mm/tlb_32.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/powerpc/mm/tlb_32.c 2007-10-29 13:54:06.000000000 -0700
@@ -144,6 +144,8 @@
{
struct vm_area_struct *mp;
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
if (Hash == 0) {
_tlbia();
return;
diff -urwNbB 2.6.23/arch/ppc/mm/tlb.c 2.6.23a/arch/ppc/mm/tlb.c
--- 2.6.23/arch/ppc/mm/tlb.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/ppc/mm/tlb.c 2007-10-29 13:54:21.000000000 -0700
@@ -144,6 +144,8 @@
{
struct vm_area_struct *mp;
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
if (Hash == 0) {
_tlbia();
return;
diff -urwNbB 2.6.23/arch/sh64/mm/fault.c 2.6.23a/arch/sh64/mm/fault.c
--- 2.6.23/arch/sh64/mm/fault.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/sh64/mm/fault.c 2007-10-29 13:55:03.000000000 -0700
@@ -517,6 +517,8 @@
++calls_to_flush_tlb_mm;
#endif
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
if (mm->context == NO_CONTEXT)
return;
diff -urwNbB 2.6.23/arch/sparc/kernel/smp.c 2.6.23a/arch/sparc/kernel/smp.c
--- 2.6.23/arch/sparc/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/sparc/kernel/smp.c 2007-10-29 13:55:22.000000000 -0700
@@ -163,6 +163,8 @@
void smp_flush_tlb_mm(struct mm_struct *mm)
{
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
if(mm->context != NO_CONTEXT) {
cpumask_t cpu_mask = mm->cpu_vm_mask;
cpu_clear(smp_processor_id(), cpu_mask);
diff -urwNbB 2.6.23/arch/sparc64/kernel/smp.c 2.6.23a/arch/sparc64/kernel/smp.c
--- 2.6.23/arch/sparc64/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/sparc64/kernel/smp.c 2007-10-29 13:56:32.000000000 -0700
@@ -1112,6 +1112,8 @@
u32 ctx = CTX_HWBITS(mm->context);
int cpu = get_cpu();
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
if (atomic_read(&mm->mm_users) == 1) {
mm->cpu_vm_mask = cpumask_of_cpu(cpu);
goto local_flush_and_out;
diff -urwNbB 2.6.23/arch/um/kernel/tlb.c 2.6.23a/arch/um/kernel/tlb.c
--- 2.6.23/arch/um/kernel/tlb.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/um/kernel/tlb.c 2007-10-29 13:57:05.000000000 -0700
@@ -402,6 +402,7 @@
void flush_tlb_mm(struct mm_struct *mm)
{
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
CHOOSE_MODE_PROC(flush_tlb_mm_tt, flush_tlb_mm_skas, mm);
}
diff -urwNbB 2.6.23/arch/x86_64/kernel/smp.c 2.6.23a/arch/x86_64/kernel/smp.c
--- 2.6.23/arch/x86_64/kernel/smp.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/x86_64/kernel/smp.c 2007-10-30 06:27:20.000000000 -0700
@@ -229,6 +229,8 @@
{
cpumask_t cpu_mask;
+ clear_bit(MMF_NEED_FLUSH, &mm->flags);
+
preempt_disable();
cpu_mask = mm->cpu_vm_mask;
cpu_clear(smp_processor_id(), cpu_mask);
diff -urwNbB 2.6.23/arch/xtensa/mm/tlb.c 2.6.23a/arch/xtensa/mm/tlb.c
--- 2.6.23/arch/xtensa/mm/tlb.c 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/arch/xtensa/mm/tlb.c 2007-10-29 13:57:26.000000000 -0700
@@ -63,6 +63,8 @@
void flush_tlb_mm(struct mm_struct *mm)
{
+ clear_bit(MMF_NNED_FLUSH, mm->flags);
+
if (mm == current->active_mm) {
int flags;
local_save_flags(flags);
diff -urwNbB 2.6.23/include/asm-generic/tlb.h 2.6.23a/include/asm-generic/tlb.h
--- 2.6.23/include/asm-generic/tlb.h 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/include/asm-generic/tlb.h 2007-11-30 08:04:09.000000000 -0800
@@ -145,4 +145,23 @@
#define tlb_migrate_finish(mm) do {} while (0)
+/* flush an mm that we messed with earlier, but delayed the flush
+ assuming that we would muck with it a whole lot more. */
+static inline void maybe_flush_tlb_mm(struct mm_struct *mm)
+{
+ if (test_and_clear_bit(MMF_NEED_FLUSH, &mm->flags))
+ flush_tlb_mm(mm);
+}
+
+/* possibly flag an mm as needing to be flushed. */
+static inline int maybe_need_flush_mm(struct mm_struct *mm)
+{
+ if (!cpus_empty(mm->cpu_vm_mask)) {
+ set_bit(MMF_NEED_FLUSH, &mm->flags);
+ return 1;
+ }
+ return 0;
+}
+
+
#endif /* _ASM_GENERIC__TLB_H */
diff -urwNbB 2.6.23/include/linux/sched.h 2.6.23a/include/linux/sched.h
--- 2.6.23/include/linux/sched.h 2007-10-09 13:31:38.000000000 -0700
+++ 2.6.23a/include/linux/sched.h 2007-10-29 13:44:30.000000000 -0700
@@ -366,6 +366,9 @@
#define MMF_DUMP_FILTER_DEFAULT \
((1 << MMF_DUMP_ANON_PRIVATE) | (1 << MMF_DUMP_ANON_SHARED))
+/* Misc MM flags. */
+#define MMF_NEED_FLUSH 6
+
struct mm_struct {
struct vm_area_struct * mmap; /* list of VMAs */
struct rb_root mm_rb;
reply other threads:[~2007-11-30 16:35 UTC|newest]
Thread overview: [no followups] expand[flat|nested] mbox.gz Atom feed
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=d43160c70711300835i3f4bb3e0n74d6ee4ff2a8167@mail.gmail.com \
--to=rossb@google.com \
--cc=MELGOR@ie.ibm.com \
--cc=haveblue@us.ibm.com \
--cc=linux-mm@kvack.org \
--cc=mel@skynet.ie \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).