patch-2.1.9 linux/arch/sparc/mm/asyncd.c

• Lines: 190
• Date: Sat Nov 9 10:12:15 1996
• Orig file: v2.1.8/linux/arch/sparc/mm/asyncd.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v2.1.8/linux/arch/sparc/mm/asyncd.c linux/arch/sparc/mm/asyncd.c
@@ -0,0 +1,189 @@
+/*  $Id: asyncd.c,v 1.8 1996/09/21 04:30:12 davem Exp $
+ *  The asyncd kernel daemon. This handles paging on behalf of 
+ *  processes that receive page faults due to remote (async) memory
+ *  accesses. 
+ *
+ *  Idea and skeleton code courtesy of David Miller (bless his cotton socks)
+ *
+ *  Implemented by tridge
+ */
+
+#include <linux/mm.h>
+#include <linux/malloc.h>
+#include <linux/sched.h>
+#include <linux/head.h>
+#include <linux/kernel.h>
+#include <linux/kernel_stat.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/swap.h>
+#include <linux/fs.h>
+
+#include <asm/dma.h>
+#include <asm/system.h> /* for cli()/sti() */
+#include <asm/segment.h> /* for memcpy_to/fromfs */
+#include <asm/bitops.h>
+#include <asm/pgtable.h>
+
+/* 
+ * The wait queue for waking up the async daemon:
+ */
+static struct wait_queue * asyncd_wait = NULL;
+
+struct async_job {
+	volatile struct async_job *next;
+	int taskid;
+	struct mm_struct *mm;
+	unsigned long address;
+	int write;
+	void (*callback)(int,unsigned long,int,int);
+};
+
+static volatile struct async_job *async_queue = NULL;
+static volatile struct async_job *async_queue_end = NULL;
+
+static void add_to_async_queue(int taskid,
+			       struct mm_struct *mm,
+			       unsigned long address,
+			       int write,
+			       void (*callback)(int,unsigned long,int,int))
+{
+	struct async_job *a = kmalloc(sizeof(*a),GFP_ATOMIC);
+
+	if (!a)
+		panic("out of memory in asyncd\n");
+
+	a->next = NULL;
+	a->taskid = taskid;
+	a->mm = mm;
+	a->address = address;
+	a->write = write;
+	a->callback = callback;
+
+	if (!async_queue) {
+		async_queue = a;
+	} else {
+		async_queue_end->next = a;
+	}
+	async_queue_end = a;
+}
+
+
+void async_fault(unsigned long address, int write, int taskid,
+		 void (*callback)(int,unsigned long,int,int))
+{
+	struct task_struct *tsk = task[taskid];
+	struct mm_struct *mm = tsk->mm;
+
+#if 0
+	printk("paging in %x for task=%d\n",address,taskid);
+#endif
+	add_to_async_queue(taskid, mm, address, write, callback);
+	wake_up(&asyncd_wait);  
+}
+
+static int fault_in_page(int taskid,
+			 struct vm_area_struct *vma,
+			 unsigned address,int write)
+{
+	struct task_struct *tsk = task[taskid];
+	pgd_t *pgd;
+	pmd_t *pmd;
+	pte_t *pte;
+
+	if (!tsk || !tsk->mm)
+		return 1;
+
+	if (!vma || (write && !(vma->vm_flags & VM_WRITE)))
+	  goto bad_area;
+	if (vma->vm_start > address)
+	  goto bad_area;
+	
+	pgd = pgd_offset(vma->vm_mm, address);
+	pmd = pmd_alloc(pgd,address);
+	if(!pmd)
+		goto no_memory;
+	pte = pte_alloc(pmd, address);
+	if(!pte)
+		goto no_memory;
+	if(!pte_present(*pte)) {
+		do_no_page(tsk, vma, address, write);
+		goto finish_up;
+	}
+	set_pte(pte, pte_mkyoung(*pte));
+	flush_tlb_page(vma, address);
+	if(!write)
+		goto finish_up;
+	if(pte_write(*pte)) {
+		set_pte(pte, pte_mkdirty(*pte));
+		flush_tlb_page(vma, address);
+		goto finish_up;
+	}
+	do_wp_page(tsk, vma, address, write);
+
+	/* Fall through for do_wp_page */
+finish_up:
+	update_mmu_cache(vma, address, *pte);
+	return 0;
+
+no_memory:
+	oom(tsk);
+	return 1;
+	
+bad_area:	  
+	tsk->tss.sig_address = address;
+	tsk->tss.sig_desc = SUBSIG_NOMAPPING;
+	send_sig(SIGSEGV, tsk, 1);
+	return 1;
+}
+
+/* Note the semaphore operations must be done here, and _not_
+ * in async_fault().
+ */
+static void run_async_queue(void)
+{
+	int ret;
+	while (async_queue) {
+		volatile struct async_job *a = async_queue;
+		struct mm_struct *mm = a->mm;
+		struct vm_area_struct *vma;
+		async_queue = async_queue->next;
+		down(&mm->mmap_sem);
+		vma = find_vma(mm, a->address);
+		ret = fault_in_page(a->taskid,vma,a->address,a->write);
+		a->callback(a->taskid,a->address,a->write,ret);
+		up(&mm->mmap_sem);
+		kfree_s((void *)a,sizeof(*a));
+	}
+}
+
+
+
+
+/*
+ * The background async daemon.
+ * Started as a kernel thread from the init process.
+ */
+int asyncd(void *unused)
+{
+	current->session = 1;
+	current->pgrp = 1;
+	sprintf(current->comm, "asyncd");
+	current->blocked = ~0UL; /* block all signals */
+  
+	/* Give kswapd a realtime priority. */
+	current->policy = SCHED_FIFO;
+	current->priority = 32;  /* Fixme --- we need to standardise our
+				    namings for POSIX.4 realtime scheduling
+				    priorities.  */
+  
+	printk("Started asyncd\n");
+  
+	while (1) {
+		current->signal = 0;
+		interruptible_sleep_on(&asyncd_wait);
+		run_async_queue();
+	}
+}
+