From: Suresh Siddha <suresh.b.siddha@intel.com>
To: mingo@elte.hu, hpa@zytor.com, tglx@linutronix.de,
andi@firstfloor.org, hch@infradead.org
Cc: linux-kernel@vger.kernel.org,
Suresh Siddha <suresh.b.siddha@intel.com>,
Arjan van de Ven <arjan@linux.intel.com>
Subject: [patch 2/2] x86, fpu: lazy allocation of FPU area - v2
Date: Fri, 29 Feb 2008 16:51:19 -0800 [thread overview]
Message-ID: <20080301005142.156610000@linux-os.sc.intel.com> (raw)
In-Reply-To: 20080301005141.997705000@linux-os.sc.intel.com
[-- Attachment #1: x86-lazy-fp-allocation.patch --]
[-- Type: text/plain, Size: 4477 bytes --]
Only allocate the FPU area when the application actually uses FPU, i.e., in the
first lazy FPU trap. This could save memory for non-fpu using apps.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
---
v2: Ported to x86.git#testing with some name changes.
---
Index: linux-2.6-x86/arch/x86/kernel/i387.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/kernel/i387.c 2008-02-29 16:26:08.000000000 -0800
+++ linux-2.6-x86/arch/x86/kernel/i387.c 2008-02-29 16:26:14.000000000 -0800
@@ -9,7 +9,6 @@
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/regset.h>
-#include <linux/bootmem.h>
#include <asm/processor.h>
#include <asm/i387.h>
#include <asm/math_emu.h>
@@ -67,7 +66,6 @@
else
xstate_size = sizeof(struct i387_fsave_struct);
#endif
- init_task.thread.xstate = alloc_bootmem(xstate_size);
}
#ifdef CONFIG_X86_64
@@ -105,6 +103,12 @@
return;
}
+ /*
+ * Memory allocation at the first usage of the FPU and other state.
+ */
+ if (!tsk->thread.xstate)
+ tsk->thread.xstate = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);
+
if (cpu_has_fxsr) {
struct i387_fxsave_struct *fx = &tsk->thread.xstate->fxsave;
Index: linux-2.6-x86/arch/x86/kernel/process.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/kernel/process.c 2008-02-29 16:26:08.000000000 -0800
+++ linux-2.6-x86/arch/x86/kernel/process.c 2008-02-29 16:26:14.000000000 -0800
@@ -5,24 +5,33 @@
#include <linux/slab.h>
#include <linux/sched.h>
-static struct kmem_cache *task_xstate_cachep;
+struct kmem_cache *task_xstate_cachep;
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
*dst = *src;
- dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);
- if (!dst->thread.xstate)
- return -ENOMEM;
- WARN_ON((unsigned long)dst->thread.xstate & 15);
- memcpy(dst->thread.xstate, src->thread.xstate, xstate_size);
+ if (src->thread.xstate) {
+ dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);
+ if (!dst->thread.xstate)
+ return -ENOMEM;
+ WARN_ON((unsigned long)dst->thread.xstate & 15);
+ memcpy(dst->thread.xstate, src->thread.xstate, xstate_size);
+ }
return 0;
}
-void free_thread_info(struct thread_info *ti)
+void free_thread_xstate(struct task_struct *tsk)
{
- kmem_cache_free(task_xstate_cachep, ti->task->thread.xstate);
- ti->task->thread.xstate = NULL;
+ if (tsk->thread.xstate) {
+ kmem_cache_free(task_xstate_cachep, tsk->thread.xstate);
+ tsk->thread.xstate = NULL;
+ }
+}
+
+void free_thread_info(struct thread_info *ti)
+{
+ free_thread_xstate(ti->task);
free_pages((unsigned long)(ti), get_order(THREAD_SIZE));
}
Index: linux-2.6-x86/include/asm-x86/processor.h
===================================================================
--- linux-2.6-x86.orig/include/asm-x86/processor.h 2008-02-29 16:26:08.000000000 -0800
+++ linux-2.6-x86/include/asm-x86/processor.h 2008-02-29 16:26:14.000000000 -0800
@@ -354,6 +354,8 @@
extern void print_cpu_info(struct cpuinfo_x86 *);
extern unsigned int xstate_size;
+extern void free_thread_xstate(struct task_struct *);
+extern struct kmem_cache *task_xstate_cachep;
extern void init_scattered_cpuid_features(struct cpuinfo_x86 *c);
extern unsigned int init_intel_cacheinfo(struct cpuinfo_x86 *c);
extern unsigned short num_cache_leaves;
Index: linux-2.6-x86/arch/x86/kernel/process_32.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/kernel/process_32.c 2008-02-29 16:26:08.000000000 -0800
+++ linux-2.6-x86/arch/x86/kernel/process_32.c 2008-02-29 16:26:14.000000000 -0800
@@ -524,6 +524,10 @@
regs->cs = __USER_CS;
regs->ip = new_ip;
regs->sp = new_sp;
+ /*
+ * Free the old FP and other extended state
+ */
+ free_thread_xstate(current);
}
EXPORT_SYMBOL_GPL(start_thread);
Index: linux-2.6-x86/arch/x86/kernel/process_64.c
===================================================================
--- linux-2.6-x86.orig/arch/x86/kernel/process_64.c 2008-02-29 16:26:08.000000000 -0800
+++ linux-2.6-x86/arch/x86/kernel/process_64.c 2008-02-29 16:26:14.000000000 -0800
@@ -552,6 +552,10 @@
regs->ss = __USER_DS;
regs->flags = 0x200;
set_fs(USER_DS);
+ /*
+ * Free the old FP and other extended state
+ */
+ free_thread_xstate(current);
}
EXPORT_SYMBOL_GPL(start_thread);
--
next prev parent reply other threads:[~2008-03-01 1:19 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-01 0:51 [patch 1/2] x86, fpu: split FPU state from task struct - v2 Suresh Siddha
2008-03-01 0:51 ` Suresh Siddha [this message]
2008-03-01 12:41 ` [patch 2/2] x86, fpu: lazy allocation of FPU area " Andi Kleen
2008-03-03 8:50 ` [patch 1/2] x86, fpu: split FPU state from task struct " Ingo Molnar
2008-03-03 9:14 ` Ingo Molnar
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=20080301005142.156610000@linux-os.sc.intel.com \
--to=suresh.b.siddha@intel.com \
--cc=andi@firstfloor.org \
--cc=arjan@linux.intel.com \
--cc=hch@infradead.org \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=tglx@linutronix.de \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.