Attachment 246880 Details for Bug 275436 – revised patch/proof of concept

[patch] revised patch/proof of concept

tmpfs.mem.patch2 (text/plain), 2.90 KB, created by Mike Karels on 2023-12-07 18:43:38 UTC

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Creator: Mike Karels

Created: 2023-12-07 18:43:38 UTC

Size: 2.90 KB

patch

obsolete

>diff --git a/sys/fs/tmpfs/tmpfs.h b/sys/fs/tmpfs/tmpfs.h
>index 7ebdffbec84f..5c86a386b9da 100644
>--- a/sys/fs/tmpfs/tmpfs.h
>+++ b/sys/fs/tmpfs/tmpfs.h
>@@ -543,6 +543,14 @@ tmpfs_update(struct vnode *vp)
> #define TMPFS_PAGES_MINRESERVED		(4 * 1024 * 1024 / PAGE_SIZE)
> #endif
> 
>+/*
>+ * Percent of available memory + swap available to use by tmpfs file systems
>+ * without a size limit.
>+ */
>+#if !defined(TMPFS_MEM_PERCENT)
>+#define TMPFS_MEM_PERCENT		95
>+#endif
>+
> /*
>  * Amount of memory to reserve for extended attributes.
>  */
>diff --git a/sys/fs/tmpfs/tmpfs_subr.c b/sys/fs/tmpfs/tmpfs_subr.c
>index 2fe7f7e3ca58..39d24b131c2e 100644
>--- a/sys/fs/tmpfs/tmpfs_subr.c
>+++ b/sys/fs/tmpfs/tmpfs_subr.c
>@@ -73,6 +73,9 @@ SYSCTL_NODE(_vfs, OID_AUTO, tmpfs, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
>     "tmpfs file system");
> 
> static long tmpfs_pages_reserved = TMPFS_PAGES_MINRESERVED;
>+static long tmpfs_pages_avail_init;
>+static int tmpfs_mem_percent = TMPFS_MEM_PERCENT;
>+static void tmpfs_set_reserve_from_percent(void);
> 
> MALLOC_DEFINE(M_TMPFSDIR, "tmpfs dir", "tmpfs dirent structure");
> static uma_zone_t tmpfs_node_pool;
>@@ -290,6 +293,8 @@ tmpfs_can_alloc_page(vm_object_t obj, vm_pindex_t pindex)
> 	if (tm == NULL || vm_pager_has_page(obj, pindex, NULL, NULL) ||
> 	    tm->tm_pages_max == 0)
> 		return (true);
>+	if (tm->tm_pages_max == ULONG_MAX)
>+		return (tmpfs_mem_avail() >= 1);
> 	return (tm->tm_pages_max > atomic_load_long(&tm->tm_pages_used));
> }
> 
>@@ -365,6 +370,9 @@ tmpfs_subr_init(void)
> 	    sizeof(struct tmpfs_node), tmpfs_node_ctor, tmpfs_node_dtor,
> 	    tmpfs_node_init, tmpfs_node_fini, UMA_ALIGN_PTR, 0);
> 	VFS_SMR_ZONE_SET(tmpfs_node_pool);
>+
>+	tmpfs_pages_avail_init = tmpfs_mem_avail();
>+	tmpfs_set_reserve_from_percent();
> 	return (0);
> }
> 
>@@ -403,6 +411,41 @@ SYSCTL_PROC(_vfs_tmpfs, OID_AUTO, memory_reserved,
>     sysctl_mem_reserved, "L",
>     "Amount of available memory and swap below which tmpfs growth stops");
> 
>+static int
>+sysctl_mem_percent(SYSCTL_HANDLER_ARGS)
>+{
>+	int error, percent;
>+
>+	percent = *(int *)arg1;
>+	error = sysctl_handle_int(oidp, &percent, 0, req);
>+	if (error || !req->newptr)
>+		return (error);
>+
>+	if ((unsigned) percent > 100)
>+		return (EINVAL);
>+
>+	*(long *)arg1 = percent;
>+	tmpfs_set_reserve_from_percent();
>+	return (0);
>+}
>+
>+static void
>+tmpfs_set_reserve_from_percent(void)
>+{
>+	size_t reserved;
>+
>+	reserved = tmpfs_pages_avail_init * (100 - tmpfs_mem_percent) / 100;
>+	if (reserved < TMPFS_PAGES_MINRESERVED)
>+		tmpfs_pages_reserved = TMPFS_PAGES_MINRESERVED;
>+	else
>+		tmpfs_pages_reserved = reserved;
>+}
>+
>+SYSCTL_PROC(_vfs_tmpfs, OID_AUTO, mem_percent,
>+    CTLTYPE_INT|CTLFLAG_MPSAFE|CTLFLAG_RW, &tmpfs_mem_percent, 0,
>+    sysctl_mem_percent, "I",
>+    "Percent of available memory that can be used if no size limit");
>+
> static __inline int tmpfs_dirtree_cmp(struct tmpfs_dirent *a,
>     struct tmpfs_dirent *b);
> RB_PROTOTYPE_STATIC(tmpfs_dir, tmpfs_dirent, uh.td_entries, tmpfs_dirtree_cmp);

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Attachments on bug 275436: 246673 | 246718 | 246880