Attachment 187384 Details for Bug 223015 – POC for using resident_page_count

[patch] POC for using resident_page_count

tmpfs.diff (text/plain), 3.20 KB, created by Keith White on 2017-10-22 23:53:45 UTC

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Creator: Keith White

Created: 2017-10-22 23:53:45 UTC

Size: 3.20 KB

patch

obsolete

>Index: /usr/src/sys/fs/tmpfs/tmpfs_subr.c
>===================================================================
>--- /usr/src/sys/fs/tmpfs/tmpfs_subr.c	(revision 324624)
>+++ /usr/src/sys/fs/tmpfs/tmpfs_subr.c	(working copy)
>@@ -351,7 +351,7 @@
> 		uobj = node->tn_reg.tn_aobj;
> 		if (uobj != NULL) {
> 			if (uobj->size != 0)
>-				atomic_subtract_long(&tmp->tm_pages_used, uobj->size);
>+				atomic_subtract_long(&tmp->tm_pages_used, uobj->resident_page_count);
> 			KASSERT((uobj->flags & OBJ_TMPFS) == 0,
> 			    ("leaked OBJ_TMPFS node %p vm_obj %p", node, uobj));
> 			vm_object_deallocate(uobj);
>@@ -1361,7 +1361,7 @@
> 	struct tmpfs_node *node;
> 	vm_object_t uobj;
> 	vm_page_t m;
>-	vm_pindex_t idx, newpages, oldpages;
>+	vm_pindex_t idx, newpages, oldpages, oldresident, newresident;
> 	off_t oldsize;
> 	int base, rv;
> 
>@@ -1379,6 +1379,7 @@
> 	 * its own.
> 	 */
> 	oldsize = node->tn_size;
>+	oldresident = uobj->resident_page_count;
> 	oldpages = OFF_TO_IDX(oldsize + PAGE_MASK);
> 	MPASS(oldpages == uobj->size);
> 	newpages = OFF_TO_IDX(newsize + PAGE_MASK);
>@@ -1388,10 +1389,6 @@
> 		return (0);
> 	}
> 
>-	if (newpages > oldpages &&
>-	    tmpfs_pages_check_avail(tmp, newpages - oldpages) == 0)
>-		return (ENOSPC);
>-
> 	VM_OBJECT_WLOCK(uobj);
> 	if (newsize < oldsize) {
> 		/*
>@@ -1457,9 +1454,11 @@
> 		}
> 	}
> 	uobj->size = newpages;
>+	newresident = uobj->resident_page_count;
>+
> 	VM_OBJECT_WUNLOCK(uobj);
> 
>-	atomic_add_long(&tmp->tm_pages_used, newpages - oldpages);
>+	atomic_add_long(&tmp->tm_pages_used, newresident - oldresident);
> 
> 	node->tn_size = newsize;
> 	return (0);
>Index: /usr/src/sys/fs/tmpfs/tmpfs_vnops.c
>===================================================================
>--- /usr/src/sys/fs/tmpfs/tmpfs_vnops.c	(revision 324624)
>+++ /usr/src/sys/fs/tmpfs/tmpfs_vnops.c	(working copy)
>@@ -488,6 +488,8 @@
> 	struct tmpfs_node *node;
> 	off_t oldsize;
> 	int error, ioflag;
>+	vm_pindex_t oldresident, newresident;
>+	struct tmpfs_mount *tmp;
> 
> 	vp = v->a_vp;
> 	uio = v->a_uio;
>@@ -494,7 +496,9 @@
> 	ioflag = v->a_ioflag;
> 	error = 0;
> 	node = VP_TO_TMPFS_NODE(vp);
>+	oldresident = node->tn_reg.tn_aobj->resident_page_count;
> 	oldsize = node->tn_size;
>+	tmp = VFS_TO_TMPFS(vp->v_mount);
> 
> 	if (uio->uio_offset < 0 || vp->v_type != VREG)
> 		return (EINVAL);
>@@ -502,11 +506,13 @@
> 		return (0);
> 	if (ioflag & IO_APPEND)
> 		uio->uio_offset = node->tn_size;
>-	if (uio->uio_offset + uio->uio_resid >
>-	  VFS_TO_TMPFS(vp->v_mount)->tm_maxfilesize)
>+	if (uio->uio_offset + uio->uio_resid > tmp->tm_maxfilesize)
> 		return (EFBIG);
> 	if (vn_rlimit_fsize(vp, uio, uio->uio_td))
> 		return (EFBIG);
>+/* XXX need to check for vm_object with holes, this test is simplistic XXX */
>+	if (tmp->tm_pages_used + howmany(uio->uio_resid, PAGE_SIZE) >= tmp->tm_pages_max)
>+		return(ENOSPC);
> 	if (uio->uio_offset + uio->uio_resid > node->tn_size) {
> 		error = tmpfs_reg_resize(vp, uio->uio_offset + uio->uio_resid,
> 		    FALSE);
>@@ -524,6 +530,9 @@
> 	if (error != 0)
> 		(void)tmpfs_reg_resize(vp, oldsize, TRUE);
> 
>+	newresident = node->tn_reg.tn_aobj->resident_page_count;
>+	if (newresident != oldresident)
>+		atomic_add_long(&tmp->tm_pages_used, newresident - oldresident);
> out:
> 	MPASS(IMPLIES(error == 0, uio->uio_resid == 0));
> 	MPASS(IMPLIES(error != 0, oldsize == node->tn_size));

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Attachments on bug 223015: 187197 | 187384