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authorgleb <gleb@FreeBSD.org>2012-04-07 15:23:51 +0000
committergleb <gleb@FreeBSD.org>2012-04-07 15:23:51 +0000
commitc4ba84f86e0e1f38a9b7138ac26876c1b293d20f (patch)
treea1ae0c42f1a9be9480e7e83902f2cecbf1671e5d /sys/fs/tmpfs
parentccd4f1d859903108662a41c03b085705ba7d8219 (diff)
downloadFreeBSD-src-c4ba84f86e0e1f38a9b7138ac26876c1b293d20f.zip
FreeBSD-src-c4ba84f86e0e1f38a9b7138ac26876c1b293d20f.tar.gz
Add reserved memory limit sysctl to tmpfs.
Cleanup availble and used memory functions. Check if free pages available before allocating new node. Discussed with: delphij
Diffstat (limited to 'sys/fs/tmpfs')
-rw-r--r--sys/fs/tmpfs/tmpfs.h57
-rw-r--r--sys/fs/tmpfs/tmpfs_subr.c67
-rw-r--r--sys/fs/tmpfs/tmpfs_vfsops.c28
3 files changed, 91 insertions, 61 deletions
diff --git a/sys/fs/tmpfs/tmpfs.h b/sys/fs/tmpfs/tmpfs.h
index efa7c6d..fad97ac 100644
--- a/sys/fs/tmpfs/tmpfs.h
+++ b/sys/fs/tmpfs/tmpfs.h
@@ -337,11 +337,10 @@ struct tmpfs_mount {
* system, set during mount time. This variable must never be
* used directly as it may be bigger than the current amount of
* free memory; in the extreme case, it will hold the SIZE_MAX
- * value. Instead, use the TMPFS_PAGES_MAX macro. */
+ * value. */
size_t tm_pages_max;
- /* Number of pages in use by the file system. Cannot be bigger
- * than the value returned by TMPFS_PAGES_MAX in any case. */
+ /* Number of pages in use by the file system. */
size_t tm_pages_used;
/* Pointer to the node representing the root directory of this
@@ -486,57 +485,15 @@ int tmpfs_truncate(struct vnode *, off_t);
* Memory management stuff.
*/
-/* Amount of memory pages to reserve for the system (e.g., to not use by
- * tmpfs).
- * XXX: Should this be tunable through sysctl, for instance? */
-#define TMPFS_PAGES_RESERVED (4 * 1024 * 1024 / PAGE_SIZE)
-
/*
- * Returns information about the number of available memory pages,
- * including physical and virtual ones.
- *
- * Remember to remove TMPFS_PAGES_RESERVED from the returned value to avoid
- * excessive memory usage.
- *
+ * Amount of memory pages to reserve for the system (e.g., to not use by
+ * tmpfs).
*/
-static __inline size_t
-tmpfs_mem_info(void)
-{
-
- return (swap_pager_avail + cnt.v_free_count + cnt.v_cache_count);
-}
-
-/* Returns the maximum size allowed for a tmpfs file system. This macro
- * must be used instead of directly retrieving the value from tm_pages_max.
- * The reason is that the size of a tmpfs file system is dynamic: it lets
- * the user store files as long as there is enough free memory (including
- * physical memory and swap space). Therefore, the amount of memory to be
- * used is either the limit imposed by the user during mount time or the
- * amount of available memory, whichever is lower. To avoid consuming all
- * the memory for a given mount point, the system will always reserve a
- * minimum of TMPFS_PAGES_RESERVED pages, which is also taken into account
- * by this macro (see above). */
-static __inline size_t
-TMPFS_PAGES_MAX(struct tmpfs_mount *tmp)
-{
- size_t freepages;
-
- freepages = tmpfs_mem_info();
- freepages -= freepages < TMPFS_PAGES_RESERVED ?
- freepages : TMPFS_PAGES_RESERVED;
-
- return MIN(tmp->tm_pages_max, freepages + tmp->tm_pages_used);
-}
+#define TMPFS_PAGES_MINRESERVED (4 * 1024 * 1024 / PAGE_SIZE)
-/* Returns the available space for the given file system. */
-#define TMPFS_META_PAGES(tmp) (howmany((tmp)->tm_nodes_inuse * (sizeof(struct tmpfs_node) \
- + sizeof(struct tmpfs_dirent)), PAGE_SIZE))
-#define TMPFS_FILE_PAGES(tmp) ((tmp)->tm_pages_used)
+size_t tmpfs_mem_avail(void);
-#define TMPFS_PAGES_AVAIL(tmp) (TMPFS_PAGES_MAX(tmp) > \
- TMPFS_META_PAGES(tmp)+TMPFS_FILE_PAGES(tmp)? \
- TMPFS_PAGES_MAX(tmp) - TMPFS_META_PAGES(tmp) \
- - TMPFS_FILE_PAGES(tmp):0)
+size_t tmpfs_pages_used(struct tmpfs_mount *tmp);
#endif
diff --git a/sys/fs/tmpfs/tmpfs_subr.c b/sys/fs/tmpfs/tmpfs_subr.c
index fe596aa..cd0e243 100644
--- a/sys/fs/tmpfs/tmpfs_subr.c
+++ b/sys/fs/tmpfs/tmpfs_subr.c
@@ -59,6 +59,69 @@ __FBSDID("$FreeBSD$");
SYSCTL_NODE(_vfs, OID_AUTO, tmpfs, CTLFLAG_RW, 0, "tmpfs file system");
+static long tmpfs_pages_reserved = TMPFS_PAGES_MINRESERVED;
+
+static int
+sysctl_mem_reserved(SYSCTL_HANDLER_ARGS)
+{
+ int error;
+ long pages, bytes;
+
+ pages = *(long *)arg1;
+ bytes = pages * PAGE_SIZE;
+
+ error = sysctl_handle_long(oidp, &bytes, 0, req);
+ if (error || !req->newptr)
+ return (error);
+
+ pages = bytes / PAGE_SIZE;
+ if (pages < TMPFS_PAGES_MINRESERVED)
+ return (EINVAL);
+
+ *(long *)arg1 = pages;
+ return (0);
+}
+
+SYSCTL_PROC(_vfs_tmpfs, OID_AUTO, memory_reserved, CTLTYPE_LONG|CTLFLAG_RW,
+ &tmpfs_pages_reserved, 0, sysctl_mem_reserved, "L", "reserved memory");
+
+size_t
+tmpfs_mem_avail(void)
+{
+ vm_ooffset_t avail;
+
+ avail = swap_pager_avail + cnt.v_free_count + cnt.v_cache_count -
+ tmpfs_pages_reserved;
+ if (__predict_false(avail < 0))
+ avail = 0;
+ return (avail);
+}
+
+size_t
+tmpfs_pages_used(struct tmpfs_mount *tmp)
+{
+ const size_t node_size = sizeof(struct tmpfs_node) +
+ sizeof(struct tmpfs_dirent);
+ size_t meta_pages;
+
+ meta_pages = howmany((uintmax_t)tmp->tm_nodes_inuse * node_size,
+ PAGE_SIZE);
+ return (meta_pages + tmp->tm_pages_used);
+}
+
+static size_t
+tmpfs_pages_check_avail(struct tmpfs_mount *tmp, size_t req_pages)
+{
+ if (tmpfs_mem_avail() < req_pages)
+ return (0);
+
+ if (tmp->tm_pages_max != SIZE_MAX &&
+ tmp->tm_pages_max < req_pages + tmpfs_pages_used(tmp))
+ return (0);
+
+ return (1);
+}
+
/* --------------------------------------------------------------------- */
/*
@@ -99,6 +162,8 @@ tmpfs_alloc_node(struct tmpfs_mount *tmp, enum vtype type,
if (tmp->tm_nodes_inuse >= tmp->tm_nodes_max)
return (ENOSPC);
+ if (tmpfs_pages_check_avail(tmp, 1) == 0)
+ return (ENOSPC);
nnode = (struct tmpfs_node *)uma_zalloc_arg(
tmp->tm_node_pool, tmp, M_WAITOK);
@@ -917,7 +982,7 @@ tmpfs_reg_resize(struct vnode *vp, off_t newsize, boolean_t ignerr)
MPASS(oldpages == uobj->size);
newpages = OFF_TO_IDX(newsize + PAGE_MASK);
if (newpages > oldpages &&
- newpages - oldpages > TMPFS_PAGES_AVAIL(tmp))
+ tmpfs_pages_check_avail(tmp, newpages - oldpages) == 0)
return (ENOSPC);
VM_OBJECT_LOCK(uobj);
diff --git a/sys/fs/tmpfs/tmpfs_vfsops.c b/sys/fs/tmpfs/tmpfs_vfsops.c
index e04c410..0afc809 100644
--- a/sys/fs/tmpfs/tmpfs_vfsops.c
+++ b/sys/fs/tmpfs/tmpfs_vfsops.c
@@ -183,7 +183,7 @@ tmpfs_mount(struct mount *mp)
/* Do not allow mounts if we do not have enough memory to preserve
* the minimum reserved pages. */
- if (tmpfs_mem_info() < TMPFS_PAGES_RESERVED)
+ if (tmpfs_mem_avail() < TMPFS_PAGES_MINRESERVED)
return ENOSPC;
/* Get the maximum number of memory pages this file system is
@@ -382,22 +382,30 @@ tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags,
static int
tmpfs_statfs(struct mount *mp, struct statfs *sbp)
{
- fsfilcnt_t freenodes;
struct tmpfs_mount *tmp;
+ size_t used;
tmp = VFS_TO_TMPFS(mp);
sbp->f_iosize = PAGE_SIZE;
sbp->f_bsize = PAGE_SIZE;
- sbp->f_blocks = TMPFS_PAGES_MAX(tmp);
- sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp);
-
- freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse,
- TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
-
- sbp->f_files = freenodes + tmp->tm_nodes_inuse;
- sbp->f_ffree = freenodes;
+ used = tmpfs_pages_used(tmp);
+ if (tmp->tm_pages_max != SIZE_MAX)
+ sbp->f_blocks = tmp->tm_pages_max;
+ else
+ sbp->f_blocks = used + tmpfs_mem_avail();
+ if (sbp->f_blocks <= used)
+ sbp->f_bavail = 0;
+ else
+ sbp->f_bavail = sbp->f_blocks - used;
+ sbp->f_bfree = sbp->f_bavail;
+ used = tmp->tm_nodes_inuse;
+ sbp->f_files = tmp->tm_nodes_max;
+ if (sbp->f_files <= used)
+ sbp->f_ffree = 0;
+ else
+ sbp->f_ffree = sbp->f_files - used;
/* sbp->f_owner = tmp->tn_uid; */
return 0;
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