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Revision f104d044376aadcee74605d66b8d9dc2e145782c authored by Josef Bacik on 14 October 2011, 17:56:58 UTC, committed by Josef Bacik on 19 October 2011, 19:12:57 UTC 
Btrfs: wait for ordered extents if we're in trouble when shrinking delalloc
 
The only way we actually reclaim delalloc space is waiting for the IO to
completely finish.  Usually we kick off a bunch of IO and wait for a little bit
and hope we can make our reservation, and usually this works out pretty well.
With overcommit however we can get seriously underwater if we're filling up the
disk quickly, so we need to be able to force the delalloc shrinker to wait for
the ordered IO to finish to give us a better chance of actually reclaiming
enough space to get our reservation.  Thanks,

Signed-off-by: Josef Bacik <josef@redhat.com>
1 parent bbb495c
Raw File
sysrq.c 
/*
 * Copyright (C) 2001 - 2003 Jeff Dike (jdike@addtoit.com)
 * Licensed under the GPL
 */

#include "linux/kernel.h"
#include "linux/smp.h"
#include "linux/sched.h"
#include "linux/kallsyms.h"
#include "asm/ptrace.h"
#include "sysrq.h"

/* This is declared by <linux/sched.h> */
void show_regs(struct pt_regs *regs)
{
        printk("\n");
        printk("EIP: %04lx:[<%08lx>] CPU: %d %s", 
	       0xffff & PT_REGS_CS(regs), PT_REGS_IP(regs),
	       smp_processor_id(), print_tainted());
        if (PT_REGS_CS(regs) & 3)
                printk(" ESP: %04lx:%08lx", 0xffff & PT_REGS_SS(regs),
		       PT_REGS_SP(regs));
        printk(" EFLAGS: %08lx\n    %s\n", PT_REGS_EFLAGS(regs),
	       print_tainted());
        printk("EAX: %08lx EBX: %08lx ECX: %08lx EDX: %08lx\n",
                PT_REGS_EAX(regs), PT_REGS_EBX(regs), 
	       PT_REGS_ECX(regs), 
	       PT_REGS_EDX(regs));
        printk("ESI: %08lx EDI: %08lx EBP: %08lx",
	       PT_REGS_ESI(regs), PT_REGS_EDI(regs), 
	       PT_REGS_EBP(regs));
        printk(" DS: %04lx ES: %04lx\n",
	       0xffff & PT_REGS_DS(regs), 
	       0xffff & PT_REGS_ES(regs));

        show_trace(NULL, (unsigned long *) &regs);
}

/* Copied from i386. */
static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
{
	return	p > (void *)tinfo &&
		p < (void *)tinfo + THREAD_SIZE - 3;
}

/* Adapted from i386 (we also print the address we read from). */
static inline unsigned long print_context_stack(struct thread_info *tinfo,
				unsigned long *stack, unsigned long ebp)
{
	unsigned long addr;

#ifdef CONFIG_FRAME_POINTER
	while (valid_stack_ptr(tinfo, (void *)ebp)) {
		addr = *(unsigned long *)(ebp + 4);
		printk("%08lx:  [<%08lx>]", ebp + 4, addr);
		print_symbol(" %s", addr);
		printk("\n");
		ebp = *(unsigned long *)ebp;
	}
#else
	while (valid_stack_ptr(tinfo, stack)) {
		addr = *stack;
		if (__kernel_text_address(addr)) {
			printk("%08lx:  [<%08lx>]", (unsigned long) stack, addr);
			print_symbol(" %s", addr);
			printk("\n");
		}
		stack++;
	}
#endif
	return ebp;
}

void show_trace(struct task_struct* task, unsigned long * stack)
{
	unsigned long ebp;
	struct thread_info *context;

	/* Turn this into BUG_ON if possible. */
	if (!stack) {
		stack = (unsigned long*) &stack;
		printk("show_trace: got NULL stack, implicit assumption task == current");
		WARN_ON(1);
	}

	if (!task)
		task = current;

	if (task != current) {
		ebp = (unsigned long) KSTK_EBP(task);
	} else {
		asm ("movl %%ebp, %0" : "=r" (ebp) : );
	}

	context = (struct thread_info *)
		((unsigned long)stack & (~(THREAD_SIZE - 1)));
	print_context_stack(context, stack, ebp);

	printk("\n");
}
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