hi all,
here's the mincore implementation again, with some improvements thanks to
Jeff Garzik and Chris Wing.
- mincore no longer uses vmalloc
- mincore can scan through arbitrarily large vm areas using only a fixed
amount of kernel memory
- vm_operations_struct instantiations use the new method which declares
only the structure fields needed, the rest being initialized as zero
- mincore_area loop rewritten to extract the "if"
- default incore function added, which simply checks pte_present
comments welcome.
diff -ruN Linux-2.3.40-3/arch/i386/kernel/entry.S linux/arch/i386/kernel/entry.S
--- Linux-2.3.40-3/arch/i386/kernel/entry.S Tue Jan 11 12:40:43 2000
+++ linux/arch/i386/kernel/entry.S Wed Jan 19 18:14:46 2000
@@ -617,6 +617,7 @@
.long SYMBOL_NAME(sys_setgid)
.long SYMBOL_NAME(sys_setfsuid) /* 215 */
.long SYMBOL_NAME(sys_setfsgid)
+ .long SYMBOL_NAME(sys_mincore)
/*
@@ -625,6 +626,6 @@
* entries. Don't panic if you notice that this hasn't
* been shrunk every time we add a new system call.
*/
- .rept NR_syscalls-216
+ .rept NR_syscalls-217
.long SYMBOL_NAME(sys_ni_syscall)
.endr
diff -ruN Linux-2.3.40-3/drivers/sgi/char/graphics.c linux/drivers/sgi/char/graphics.c
--- Linux-2.3.40-3/drivers/sgi/char/graphics.c Tue Jan 11 12:33:01 2000
+++ linux/drivers/sgi/char/graphics.c Wed Jan 19 17:41:48 2000
@@ -254,15 +254,7 @@
*/
static struct vm_operations_struct graphics_mmap = {
- NULL, /* no special mmap-open */
- NULL, /* no special mmap-close */
- NULL, /* no special mmap-unmap */
- NULL, /* no special mmap-protect */
- NULL, /* no special mmap-sync */
- NULL, /* no special mmap-advise */
- sgi_graphics_nopage, /* our magic no-page fault handler */
- NULL, /* no special mmap-wppage */
- NULL /* no special mmap-swapout */
+ nopage: sgi_graphics_nopage, /* our magic no-page fault handler */
};
int
diff -ruN Linux-2.3.40-3/drivers/sgi/char/shmiq.c linux/drivers/sgi/char/shmiq.c
--- Linux-2.3.40-3/drivers/sgi/char/shmiq.c Tue Jan 11 12:33:01 2000
+++ linux/drivers/sgi/char/shmiq.c Wed Jan 19 17:42:12 2000
@@ -296,15 +296,7 @@
}
static struct vm_operations_struct qcntl_mmap = {
- NULL, /* no special mmap-open */
- NULL, /* no special mmap-close */
- NULL, /* no special mmap-unmap */
- NULL, /* no special mmap-protect */
- NULL, /* no special mmap-sync */
- NULL, /* no special mmap-advise */
- shmiq_nopage, /* our magic no-page fault handler */
- NULL, /* no special mmap-wppage */
- NULL /* no special mmap-swapout */
+ nopage: shmiq_nopage, /* our magic no-page fault handler */
};
static int
diff -ruN Linux-2.3.40-3/fs/ncpfs/mmap.c linux/fs/ncpfs/mmap.c
--- Linux-2.3.40-3/fs/ncpfs/mmap.c Wed Nov 24 16:47:44 1999
+++ linux/fs/ncpfs/mmap.c Wed Jan 19 17:42:47 2000
@@ -94,15 +94,7 @@
struct vm_operations_struct ncp_file_mmap =
{
- NULL, /* open */
- NULL, /* close */
- NULL, /* unmap */
- NULL, /* protect */
- NULL, /* sync */
- NULL, /* advise */
- ncp_file_mmap_nopage, /* nopage */
- NULL, /* wppage */
- NULL /* swapout */
+ nopage: ncp_file_mmap_nopage,
};
diff -ruN Linux-2.3.40-3/include/asm-i386/unistd.h linux/include/asm-i386/unistd.h
--- Linux-2.3.40-3/include/asm-i386/unistd.h Tue Jan 11 12:40:56 2000
+++ linux/include/asm-i386/unistd.h Tue Jan 18 15:25:43 2000
@@ -221,6 +221,7 @@
#define __NR_setgid32 214
#define __NR_setfsuid32 215
#define __NR_setfsgid32 216
+#define __NR_mincore 217
/* user-visible error numbers are in the range -1 - -124: see <asm-i386/errno.h> */
diff -ruN Linux-2.3.40-3/include/linux/mm.h linux/include/linux/mm.h
--- Linux-2.3.40-3/include/linux/mm.h Fri Jan 14 15:43:09 2000
+++ linux/include/linux/mm.h Wed Jan 19 17:26:47 2000
@@ -106,6 +106,7 @@
void (*protect)(struct vm_area_struct *area, unsigned long, size_t, unsigned int newprot);
int (*sync)(struct vm_area_struct *area, unsigned long, size_t, unsigned int flags);
void (*advise)(struct vm_area_struct *area, unsigned long, size_t, unsigned int advise);
+ char (*incore)(struct vm_area_struct *area, unsigned long);
struct page * (*nopage)(struct vm_area_struct * area, unsigned long address, int write_access);
struct page * (*wppage)(struct vm_area_struct * area, unsigned long address, struct page * page);
int (*swapout)(struct page *, struct file *);
@@ -383,6 +384,7 @@
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);
+extern char default_incore(struct vm_area_struct * vma, unsigned long address);
extern void vmtruncate(struct inode * inode, loff_t offset);
extern int handle_mm_fault(struct task_struct *tsk,struct vm_area_struct *vma, unsigned long address, int write_access);
extern int make_pages_present(unsigned long addr, unsigned long end);
@@ -446,6 +448,8 @@
size_t size, unsigned int flags);
extern struct page *filemap_nopage(struct vm_area_struct * area,
unsigned long address, int no_share);
+extern char filemap_incore(struct vm_area_struct * vma,
+ unsigned long pgoff);
/*
* GFP bitmasks..
diff -ruN Linux-2.3.40-3/ipc/shm.c linux/ipc/shm.c
--- Linux-2.3.40-3/ipc/shm.c Fri Jan 14 15:43:09 2000
+++ linux/ipc/shm.c Wed Jan 19 17:42:27 2000
@@ -64,6 +64,7 @@
static void killseg (int shmid);
static void shm_open (struct vm_area_struct *shmd);
static void shm_close (struct vm_area_struct *shmd);
+static char shm_incore (struct vm_area_struct *shmd, unsigned long pgoff);
static struct page * shm_nopage(struct vm_area_struct *, unsigned long, int);
static int shm_swapout(struct page *, struct file *);
#ifdef CONFIG_PROC_FS
@@ -584,15 +585,11 @@
*/
static struct vm_operations_struct shm_vm_ops = {
- shm_open, /* open - callback for a new vm-area open */
- shm_close, /* close - callback for when the vm-area is released */
- NULL, /* no need to sync pages at unmap */
- NULL, /* protect */
- NULL, /* sync */
- NULL, /* advise */
- shm_nopage, /* nopage */
- NULL, /* wppage */
- shm_swapout /* swapout */
+ open: shm_open,
+ close: shm_close,
+ incore: shm_incore,
+ nopage: shm_nopage,
+ swapout: shm_swapout,
};
/* Insert shmd into the list shp->attaches */
@@ -829,6 +826,34 @@
static int shm_swapout(struct page * page, struct file *file)
{
return 0;
+}
+
+/*
+ * is page present?
+ */
+static char shm_incore(struct vm_area_struct * shmd, unsigned long pgoff)
+{
+ char result = 0;
+ pte_t pte;
+ struct shmid_kernel * shp = (struct shmid_kernel *) shmd->vm_private_data;
+
+ down(&shp->sem);
+ if(shp != shm_lock(shp->id))
+ BUG();
+
+ pte = SHM_ENTRY(shp, pgoff);
+
+ /*
+ * the pte isn't present if the page is swapped, or if it hasn't
+ * been touched yet.
+ */
+ if (pte_present(pte))
+ result = 1;
+
+ shm_unlock(shp->id);
+ up(&shp->sem);
+
+ return result;
}
/*
diff -ruN Linux-2.3.40-3/mm/filemap.c linux/mm/filemap.c
--- Linux-2.3.40-3/mm/filemap.c Fri Jan 14 15:43:09 2000
+++ linux/mm/filemap.c Wed Jan 19 17:42:41 2000
@@ -700,6 +700,30 @@
return page;
}
+/*
+ * This predicate returns 1 if the page is "in core," otherwise 0.
+ *
+ * Later we can get more picky about what "in core" means precisely,
+ * but for now, it simply checks to see if the page is in the page
+ * cache, and is up to date; i.e. that no page-in operation would be
+ * required at this time if an application were to map and access
+ * this page.
+ */
+char filemap_incore(struct vm_area_struct * vma, unsigned long pgoff)
+{
+ char result = 0;
+ struct address_space * as = &vma->vm_file->f_dentry->d_inode->i_data;
+ struct page * page, ** hash = page_hash(as, pgoff);
+
+ spin_lock(&pagecache_lock);
+ page = __find_page_nolock(as, pgoff, *hash);
+ if ((page) && (Page_Uptodate(page)))
+ result = 1;
+ spin_unlock(&pagecache_lock);
+
+ return result;
+}
+
#if 0
#define PROFILE_READAHEAD
#define DEBUG_READAHEAD
@@ -1627,15 +1651,11 @@
* backing-store for swapping..
*/
static struct vm_operations_struct file_shared_mmap = {
- NULL, /* no special open */
- NULL, /* no special close */
- filemap_unmap, /* unmap - we need to sync the pages */
- NULL, /* no special protect */
- filemap_sync, /* sync */
- NULL, /* advise */
- filemap_nopage, /* nopage */
- NULL, /* wppage */
- filemap_swapout /* swapout */
+ unmap: filemap_unmap, /* unmap - we need to sync the pages */
+ sync: filemap_sync,
+ incore: filemap_incore,
+ nopage: filemap_nopage,
+ swapout: filemap_swapout,
};
/*
@@ -1645,15 +1665,8 @@
* know they can't ever get write permissions..)
*/
static struct vm_operations_struct file_private_mmap = {
- NULL, /* open */
- NULL, /* close */
- NULL, /* unmap */
- NULL, /* protect */
- NULL, /* sync */
- NULL, /* advise */
- filemap_nopage, /* nopage */
- NULL, /* wppage */
- NULL /* swapout */
+ incore: filemap_incore,
+ nopage: filemap_nopage,
};
/* This is used for a general mmap of a disk file */
diff -ruN Linux-2.3.40-3/mm/memory.c linux/mm/memory.c
--- Linux-2.3.40-3/mm/memory.c Tue Jan 11 12:40:57 2000
+++ linux/mm/memory.c Wed Jan 19 17:24:45 2000
@@ -412,6 +412,23 @@
return NULL;
}
+/*
+ * default vm operation for mincore() system call
+ */
+char default_incore(struct vm_area_struct * vma, unsigned long address)
+{
+ pgd_t *pgd = pgd_offset(vma->vm_mm, address);
+ pmd_t *pmd = pmd_offset(pgd, address);
+
+ if (pmd) {
+ pte_t * pte = pte_offset(pmd, address);
+ if (pte && pte_present(*pte))
+ return 1;
+ }
+
+ return 0;
+}
+
/*
* Given a physical address, is there a useful struct page pointing to it?
*/
diff -ruN Linux-2.3.40-3/mm/mmap.c linux/mm/mmap.c
--- Linux-2.3.40-3/mm/mmap.c Tue Dec 21 13:59:00 1999
+++ linux/mm/mmap.c Wed Jan 19 17:55:57 2000
@@ -720,6 +720,142 @@
}
/*
+ * If mincore_area can't find an "incore" predicate for this vma,
+ * just assume that the pages are present. This is reasonable for
+ * device drivers and file systems that don't use the page cache.
+ */
+static long mincore_area(struct vm_area_struct * vma,
+ unsigned long start, unsigned long end, char * vec)
+{
+ int remaining, error, size, i;
+ char * tmp;
+
+ start = ((start - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+ if (end > vma->vm_end)
+ end = vma->vm_end;
+ end = ((end - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+
+ /* # of bytes in "vec" = # of pages */
+ size = end - start;
+
+ tmp = (char *) __get_free_page(GFP_KERNEL);
+ if (!tmp)
+ return -ENOMEM;
+
+ error = 0;
+ for (remaining = size, i = 0;
+ remaining > 0;
+ remaining -= PAGE_SIZE, i++) {
+ int j = 0;
+ int thispiece = (remaining < PAGE_SIZE) ? remaining : PAGE_SIZE;
+
+ if (vma->vm_ops && vma->vm_ops->incore) {
+ while (j < thispiece)
+ tmp[j++] = vma->vm_ops->incore(vma, start++);
+ } else {
+ while (j < thispiece)
+ tmp[j++] = default_incore(vma, start++);
+ }
+
+ if (copy_to_user(vec + PAGE_SIZE * i, tmp, thispiece)) {
+ error = -EFAULT;
+ break;
+ }
+ }
+
+ free_page((unsigned long) tmp);
+ return error;
+}
+
+/*
+ * The mincore(2) system call.
+ *
+ * mincore() returns the memory residency status of the pages in the
+ * current process's address space specified by [addr, addr + len).
+ * The status is returned in a vector of bytes. The least significant
+ * bit of each byte is 1 if the referenced page is in memory, otherwise
+ * it is zero.
+ *
+ * Because the status of a page can change after mincore() checks it
+ * but before it returns to the application, the returned vector may
+ * contain stale information. Only locked pages are guaranteed to
+ * remain in memory.
+ *
+ * return values:
+ * zero - success
+ * -EFAULT - vec points to an illegal address
+ * -EINVAL - addr is not a multiple of PAGE_CACHE_SIZE,
+ * or len has a nonpositive value
+ * -ENOMEM - Addresses in the range [addr, addr + len] are
+ * invalid for the address space of this process, or
+ * specify one or more pages which are not currently
+ * mapped
+ */
+asmlinkage long sys_mincore(unsigned long start, size_t len, char *vec)
+{
+ int index = 0;
+ unsigned long end;
+ struct vm_area_struct * vma;
+ int unmapped_error = 0;
+ int error = -EINVAL;
+
+ down(¤t->mm->mmap_sem);
+
+ if (start & ~PAGE_MASK)
+ goto out;
+ len = (len + ~PAGE_MASK) & PAGE_MASK;
+ end = start + len;
+ if (end < start)
+ goto out;
+
+ error = 0;
+ if (end == start)
+ goto out;
+
+ /*
+ * If the interval [start,end) covers some unmapped address
+ * ranges, just ignore them, but return -ENOMEM at the end.
+ */
+ vma = find_vma(current->mm, start);
+ for (;;) {
+ /* Still start < end. */
+ error = -ENOMEM;
+ if (!vma)
+ goto out;
+
+ /* Here start < vma->vm_end. */
+ if (start < vma->vm_start) {
+ unmapped_error = -ENOMEM;
+ start = vma->vm_start;
+ }
+
+ /* Here vma->vm_start <= start < vma->vm_end. */
+ if (end <= vma->vm_end) {
+ if (start < end) {
+ error = mincore_area(vma, start, end,
+ &vec[index]);
+ if (error)
+ goto out;
+ }
+ error = unmapped_error;
+ goto out;
+ }
+
+ /* Here vma->vm_start <= start < vma->vm_end < end. */
+ error = mincore_area(vma, start, vma->vm_end, &vec[index]);
+ if (error)
+ goto out;
+ index += (vma->vm_end - start) >> PAGE_CACHE_SHIFT;
+ start = vma->vm_end;
+ vma = vma->vm_next;
+ }
+
+out:
+ up(¤t->mm->mmap_sem);
+ return error;
+}
+
+/*
* this is really a simplified "do_mmap". it only handles
* anonymous maps. eventually we may be able to do some
* brk-specific accounting here.
diff -ruN Linux-2.3.40-3/net/packet/af_packet.c linux/net/packet/af_packet.c
--- Linux-2.3.40-3/net/packet/af_packet.c Fri Dec 31 15:04:42 1999
+++ linux/net/packet/af_packet.c Wed Jan 19 17:42:55 2000
@@ -1537,15 +1537,8 @@
}
static struct vm_operations_struct packet_mmap_ops = {
- packet_mm_open, /* open */
- packet_mm_close, /* close */
- NULL, /* unmap */
- NULL, /* no special protect */
- NULL, /* sync */
- NULL, /* advise */
- NULL, /* nopage */
- NULL, /* wppage */
- NULL /* swapout */
+ open: packet_mm_open,
+ close: packet_mm_close,
};
static void free_pg_vec(unsigned long *pg_vec, unsigned order, unsigned len)
- Chuck Lever
-- corporate: <chuckl@netscape.com> personal: <chucklever@netscape.net> or <cel@monkey.org>The Linux Scalability project: http://www.citi.umich.edu/projects/linux-scalability/
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sun Jan 23 2000 - 21:00:23 EST