1021.lowlatency.patch

sm86xx内核源包括补丁（ GPL ）的

+
+void set_running_and_schedule(void);
+#define unconditional_schedule() set_running_and_schedule()
+
+#endif	/* LOWLATENCY_DEBUG */
+
+#define conditional_schedule()						\
+	do {								\
+		if (conditional_schedule_needed())			\
+			unconditional_schedule();			\
+	} while (0)
+
+#define DEFINE_RESCHED_COUNT	int resched_count = 0
+#define TEST_RESCHED_COUNT(n)	(enable_lowlatency && (++resched_count > (n)))
+#define RESET_RESCHED_COUNT()	resched_count = 0
+extern int ll_copy_to_user(void *to_user, const void *from, unsigned long len);
+extern int ll_copy_from_user(void *to, const void *from_user, unsigned long len);
+
+#else	/* LOWLATENCY_NEEDED */
+
+#define conditional_schedule_needed() 0
+#define conditional_schedule()
+#define unconditional_schedule()
+
+#define DEFINE_RESCHED_COUNT
+#define TEST_RESCHED_COUNT(n)	0
+#define RESET_RESCHED_COUNT()
+#define ll_copy_to_user(to_user, from, len) copy_to_user((to_user), (from), (len))
+#define ll_copy_from_user(to, from_user, len) copy_from_user((to), (from_user), (len))
+
+#endif	/* LOWLATENCY_NEEDED */
+
+#endif /* LOW_LATENCY_H_INCLUDED */
+
diff -Naur --exclude=CVS --exclude='*.o' --exclude='*.a' --exclude='*.so' --exclude='*.elf' --exclude=System.map --exclude=Makefile.d --exclude='*log' --exclude='*log2' --exclude='*~' --exclude='.*~' --exclude='.#*' --exclude='*.bak' --exclude='*.orig' --exclude='*.rej' --exclude='core.[0-9]*' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=vmlinux --exclude=vmlinux.bin --exclude=yamon-02.06-SIGMADESIGNS-01_el.bin linuxmips-2.4.30.ref/include/linux/mm.h linuxmips-2.4.30/include/linux/mm.h
--- linuxmips-2.4.30.ref/include/linux/mm.h	2005-07-21 19:45:37.000000000 -0700
+++ linuxmips-2.4.30/include/linux/mm.h	2005-07-22 09:36:02.000000000 -0700
@@ -124,6 +124,8 @@
  */
 extern pgprot_t protection_map[16];
 
+/* Actions for zap_page_range() */
+#define ZPR_COND_RESCHED	1	/* Do a conditional_schedule() occasionally */
 
 /*
  * These are the virtual MM functions - opening of an area, closing and
@@ -487,7 +489,7 @@
 extern void shmem_lock(struct file * file, int lock);
 extern int shmem_zero_setup(struct vm_area_struct *);
 
-extern void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size);
+extern void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size, int actions);
 extern int copy_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma);
 extern int remap_page_range(unsigned long from, unsigned long to, unsigned long size, pgprot_t prot);
 extern int zeromap_page_range(unsigned long from, unsigned long size, pgprot_t prot);
diff -Naur --exclude=CVS --exclude='*.o' --exclude='*.a' --exclude='*.so' --exclude='*.elf' --exclude=System.map --exclude=Makefile.d --exclude='*log' --exclude='*log2' --exclude='*~' --exclude='.*~' --exclude='.#*' --exclude='*.bak' --exclude='*.orig' --exclude='*.rej' --exclude='core.[0-9]*' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=vmlinux --exclude=vmlinux.bin --exclude=yamon-02.06-SIGMADESIGNS-01_el.bin linuxmips-2.4.30.ref/include/linux/reiserfs_fs.h linuxmips-2.4.30/include/linux/reiserfs_fs.h
--- linuxmips-2.4.30.ref/include/linux/reiserfs_fs.h	2004-11-18 16:28:51.000000000 -0800
+++ linuxmips-2.4.30/include/linux/reiserfs_fs.h	2005-07-22 09:36:02.000000000 -0700
@@ -1329,8 +1329,8 @@
 #define fs_generation(s) ((s)->u.reiserfs_sb.s_generation_counter)
 #define get_generation(s) atomic_read (&fs_generation(s))
 #define FILESYSTEM_CHANGED_TB(tb)  (get_generation((tb)->tb_sb) != (tb)->fs_gen)
-#define fs_changed(gen,s) (gen != get_generation (s))
-
+#define __fs_changed(gen,s) (gen != get_generation (s))
+#define fs_changed(gen,s) ({conditional_schedule(); __fs_changed(gen,s);})
 
 /***************************************************************************/
 /*                  FIXATE NODES                                           */
diff -Naur --exclude=CVS --exclude='*.o' --exclude='*.a' --exclude='*.so' --exclude='*.elf' --exclude=System.map --exclude=Makefile.d --exclude='*log' --exclude='*log2' --exclude='*~' --exclude='.*~' --exclude='.#*' --exclude='*.bak' --exclude='*.orig' --exclude='*.rej' --exclude='core.[0-9]*' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=vmlinux --exclude=vmlinux.bin --exclude=yamon-02.06-SIGMADESIGNS-01_el.bin linuxmips-2.4.30.ref/include/linux/sched.h linuxmips-2.4.30/include/linux/sched.h
--- linuxmips-2.4.30.ref/include/linux/sched.h	2005-07-21 19:45:37.000000000 -0700
+++ linuxmips-2.4.30/include/linux/sched.h	2005-07-22 09:36:02.000000000 -0700
@@ -26,6 +26,7 @@
 #include <linux/signal.h>
 #include <linux/securebits.h>
 #include <linux/fs_struct.h>
+#include <linux/low-latency.h>
 
 struct exec_domain;
 
diff -Naur --exclude=CVS --exclude='*.o' --exclude='*.a' --exclude='*.so' --exclude='*.elf' --exclude=System.map --exclude=Makefile.d --exclude='*log' --exclude='*log2' --exclude='*~' --exclude='.*~' --exclude='.#*' --exclude='*.bak' --exclude='*.orig' --exclude='*.rej' --exclude='core.[0-9]*' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=vmlinux --exclude=vmlinux.bin --exclude=yamon-02.06-SIGMADESIGNS-01_el.bin linuxmips-2.4.30.ref/include/linux/sysctl.h linuxmips-2.4.30/include/linux/sysctl.h
--- linuxmips-2.4.30.ref/include/linux/sysctl.h	2005-07-21 19:45:39.000000000 -0700
+++ linuxmips-2.4.30/include/linux/sysctl.h	2005-07-22 09:36:02.000000000 -0700
@@ -124,6 +124,7 @@
 	KERN_CORE_USES_PID=52,		/* int: use core or core.%pid */
 	KERN_TAINTED=53,	/* int: various kernel tainted flags */
 	KERN_CADPID=54,		/* int: PID of the process to notify on CAD */
+	KERN_LOWLATENCY=55,     /* int: enable low latency scheduling */
  	KERN_CORE_PATTERN=56,	/* string: pattern for core-files */
 	KERN_PPC_L3CR=57,       /* l3cr register on PPC */
 	KERN_EXCEPTION_TRACE=58, /* boolean: exception trace */
diff -Naur --exclude=CVS --exclude='*.o' --exclude='*.a' --exclude='*.so' --exclude='*.elf' --exclude=System.map --exclude=Makefile.d --exclude='*log' --exclude='*log2' --exclude='*~' --exclude='.*~' --exclude='.#*' --exclude='*.bak' --exclude='*.orig' --exclude='*.rej' --exclude='core.[0-9]*' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=vmlinux --exclude=vmlinux.bin --exclude=yamon-02.06-SIGMADESIGNS-01_el.bin linuxmips-2.4.30.ref/kernel/exit.c linuxmips-2.4.30/kernel/exit.c
--- linuxmips-2.4.30.ref/kernel/exit.c	2005-07-21 19:15:31.000000000 -0700
+++ linuxmips-2.4.30/kernel/exit.c	2005-07-22 09:36:02.000000000 -0700
@@ -196,6 +196,7 @@
 			}
 			i++;
 			set >>= 1;
+			conditional_schedule();		/* sys_exit, many files open */
 		}
 	}
 }
diff -Naur --exclude=CVS --exclude='*.o' --exclude='*.a' --exclude='*.so' --exclude='*.elf' --exclude=System.map --exclude=Makefile.d --exclude='*log' --exclude='*log2' --exclude='*~' --exclude='.*~' --exclude='.#*' --exclude='*.bak' --exclude='*.orig' --exclude='*.rej' --exclude='core.[0-9]*' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=vmlinux --exclude=vmlinux.bin --exclude=yamon-02.06-SIGMADESIGNS-01_el.bin linuxmips-2.4.30.ref/kernel/ksyms.c linuxmips-2.4.30/kernel/ksyms.c
--- linuxmips-2.4.30.ref/kernel/ksyms.c	2005-07-21 19:15:31.000000000 -0700
+++ linuxmips-2.4.30/kernel/ksyms.c	2005-07-22 09:36:02.000000000 -0700
@@ -486,6 +486,13 @@
 EXPORT_SYMBOL(do_gettimeofday);
 EXPORT_SYMBOL(do_settimeofday);
 
+#if LOWLATENCY_NEEDED
+EXPORT_SYMBOL(set_running_and_schedule);
+#ifdef CONFIG_LOLAT_SYSCTL
+EXPORT_SYMBOL(__enable_lowlatency);
+#endif
+#endif
+
 #if !defined(__ia64__)
 EXPORT_SYMBOL(loops_per_jiffy);
 #endif
diff -Naur --exclude=CVS --exclude='*.o' --exclude='*.a' --exclude='*.so' --exclude='*.elf' --exclude=System.map --exclude=Makefile.d --exclude='*log' --exclude='*log2' --exclude='*~' --exclude='.*~' --exclude='.#*' --exclude='*.bak' --exclude='*.orig' --exclude='*.rej' --exclude='core.[0-9]*' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=vmlinux --exclude=vmlinux.bin --exclude=yamon-02.06-SIGMADESIGNS-01_el.bin linuxmips-2.4.30.ref/kernel/module.c linuxmips-2.4.30/kernel/module.c
--- linuxmips-2.4.30.ref/kernel/module.c	2003-08-13 10:19:29.000000000 -0700
+++ linuxmips-2.4.30/kernel/module.c	2005-07-22 09:36:02.000000000 -0700
@@ -1187,6 +1187,11 @@
 		return ERR_PTR(-ENOMEM);
 	lock_kernel();
 	for (v = module_list, n = *pos; v; n -= v->nsyms, v = v->next) {
+#if 0
+		/* We can't actually do this, because we'd create a
+		 * race against module unload.  Need a semaphore. */
+		conditional_schedule();
+#endif
 		if (n < v->nsyms) {
 			p->mod = v;
 			p->index = n;
diff -Naur --exclude=CVS --exclude='*.o' --exclude='*.a' --exclude='*.so' --exclude='*.elf' --exclude=System.map --exclude=Makefile.d --exclude='*log' --exclude='*log2' --exclude='*~' --exclude='.*~' --exclude='.#*' --exclude='*.bak' --exclude='*.orig' --exclude='*.rej' --exclude='core.[0-9]*' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=vmlinux --exclude=vmlinux.bin --exclude=yamon-02.06-SIGMADESIGNS-01_el.bin linuxmips-2.4.30.ref/kernel/sched.c linuxmips-2.4.30/kernel/sched.c
--- linuxmips-2.4.30.ref/kernel/sched.c	2005-07-21 19:15:31.000000000 -0700
+++ linuxmips-2.4.30/kernel/sched.c	2005-07-22 09:36:02.000000000 -0700
@@ -302,6 +302,17 @@
 		if (tsk->processor != this_cpu)
 			smp_send_reschedule(tsk->processor);
 	}
+#if LOWLATENCY_NEEDED
+	if (enable_lowlatency && (p->policy != SCHED_OTHER)) {
+		struct task_struct *t;
+		for (i = 0; i < smp_num_cpus; i++) {
+			cpu = cpu_logical_map(i);
+			t = cpu_curr(cpu);
+			if (t != tsk)
+				t->need_resched = 1;
+		}
+	}
+#endif
 	return;
 		
 
@@ -638,6 +649,11 @@
 		goto repeat_schedule;
 	}
 
+	if (unlikely(prev->need_resched)) {
+		prev->need_resched = 0;
+		goto repeat_schedule;
+	}
+
 	/*
 	 * from this point on nothing can prevent us from
 	 * switching to the next task, save this fact in
@@ -1458,3 +1474,93 @@
 	atomic_inc(&init_mm.mm_count);
 	enter_lazy_tlb(&init_mm, current, cpu);
 }
+
+#if LOWLATENCY_NEEDED
+#if LOWLATENCY_DEBUG
+
+static struct lolat_stats_t *lolat_stats_head;
+static spinlock_t lolat_stats_lock = SPIN_LOCK_UNLOCKED;
+
+void set_running_and_schedule(struct lolat_stats_t *stats)
+{
+	spin_lock(&lolat_stats_lock);
+	if (stats->visited == 0) {
+		stats->visited = 1;
+		stats->next = lolat_stats_head;
+		lolat_stats_head = stats;
+	}
+	stats->count++;
+	spin_unlock(&lolat_stats_lock);
+
+	if (current->state != TASK_RUNNING)
+		set_current_state(TASK_RUNNING);
+	schedule();
+}
+
+void show_lolat_stats(void)
+{
+	struct lolat_stats_t *stats = lolat_stats_head;
+
+	printk("Low latency scheduling stats:\n");
+	while (stats) {
+		printk("%s:%d: %lu\n", stats->file, stats->line, stats->count);
+		stats->count = 0;
+		stats = stats->next;
+	}
+}
+
+#else	/* LOWLATENCY_DEBUG */
+
+void set_running_and_schedule()
+{
+	if (current->state != TASK_RUNNING)
+		__set_current_state(TASK_RUNNING);
+	schedule();
+}
+
+#endif	/* LOWLATENCY_DEBUG */
+
+int ll_copy_to_user(void *to_user, const void *from, unsigned long len)
+{
+	while (len) {
+		unsigned long n_to_copy = len;
+		unsigned long remainder;
+
+		if (n_to_copy > 4096)
+			n_to_copy = 4096;
+		len -= n_to_copy;
+		remainder = copy_to_user(to_user, from, n_to_copy);
+		if (remainder)
+			return remainder + len;
+		to_user = ((char *)to_user) + n_to_copy;
+		from = ((char *)from) + n_to_copy;
+		conditional_schedule();
+	}
+	return 0;
+}
+
+int ll_copy_from_user(void *to, const void *from_user, unsigned long len)
+{
+	while (len) {
+		unsigned long n_to_copy = len;
+		unsigned long remainder;
+
+		if (n_to_copy > 4096)
+			n_to_copy = 4096;
+		len -= n_to_copy;
+		remainder = copy_from_user(to, from_user, n_to_copy);
+		if (remainder)
+			return remainder + len;
+		to = ((char *)to) + n_to_copy;
+		from_user = ((char *)from_user) + n_to_copy;
+		conditional_schedule();
+	}
+	return 0;
+}
+
+#ifdef CONFIG_LOLAT_SYSCTL
+struct low_latency_enable_struct __enable_lowlatency = { 0, };
+#endif
+
+#endif	/* LOWLATENCY_NEEDED */
+
diff -Naur --exclude=CVS --exclude='*.o' --exclude='*.a' --exclude='*.so' --exclude='*.elf' --exclude=System.map --exclude=Makefile.d --exclude='*log' --exclude='*log2' --exclude='*~' --exclude='.*~' --exclude='.#*' --exclude='*.bak' --exclude='*.orig' --exclude='*.rej' --exclude='core.[0-9]*' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=vmlinux --exclude=vmlinux.bin --exclude=yamon-02.06-SIGMADESIGNS-01_el.bin linuxmips-2.4.30.ref/kernel/sysctl.c linuxmips-2.4.30/kernel/sysctl.c
--- linuxmips-2.4.30.ref/kernel/sysctl.c	2004-12-26 20:13:55.000000000 -0800
+++ linuxmips-2.4.30/kernel/sysctl.c	2005-07-22 09:36:02.000000000 -0700
@@ -278,6 +278,10 @@
 	{KERN_EXCEPTION_TRACE,"exception-trace",
 	 &exception_trace,sizeof(int),0644,NULL,&proc_dointvec},
 #endif	
+#ifdef CONFIG_LOLAT_SYSCTL
+	{KERN_LOWLATENCY, "lowlatency", &enable_lowlatency, sizeof (int),
+	 0644, NULL, &proc_dointvec},
+#endif
 	{0}
 };
 
diff -Naur --exclude=CVS --exclude='*.o' --exclude='*.a' --exclude='*.so' --exclude='*.elf' --exclude=System.map --exclude=Makefile.d --exclude='*log' --exclude='*log2' --exclude='*~' --exclude='.*~' --exclude='.#*' --exclude='*.bak' --exclude='*.orig' --exclude='*.rej' --exclude='core.[0-9]*' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=.depend --exclude='.*.o.flags' --exclude='*.gz' --exclude=vmlinux --exclude=vmlinux.bin --exclude=yamon-02.06-SIGMADESIGNS-01_el.bin linuxmips-2.4.30.ref/mm/filemap.c linuxmips-2.4.30/mm/filemap.c
--- linuxmips-2.4.30.ref/mm/filemap.c	2005-04-05 12:09:58.000000000 -0700
+++ linuxmips-2.4.30/mm/filemap.c	2005-07-22 09:36:02.000000000 -0700
@@ -185,7 +185,9 @@
 {
 	struct list_head *head, *curr;
 	struct page * page;
+	int ll_count = 100;
 
+restart:
 	head = &inode->i_mapping->clean_pages;
 
 	spin_lock(&pagemap_lru_lock);
@@ -196,6 +198,14 @@
 		page = list_entry(curr, struct page, list);
 		curr = curr->next;
 
+		if (conditional_schedule_needed() && ll_count) {
+			spin_unlock(&pagecache_lock);
+			spin_unlock(&pagemap_lru_lock);
+			unconditional_schedule();
+			ll_count--;
+			goto restart;
+		}
+
 		/* We cannot invalidate something in dirty.. */
 		if (PageDirty(page))
 			continue;
@@ -259,8 +269,8 @@
 	page_cache_release(page);
 }
 
-static int FASTCALL(truncate_list_pages(struct list_head *, unsigned long, unsigned *));
-static int fastcall truncate_list_pages(struct list_head *head, unsigned long start, unsigned *partial)
+static int truncate_list_pages(struct list_head *head, unsigned long start,
+				unsigned *partial, int *restart_count)