diff options
| author | Baoquan He <bhe@redhat.com> | 2023-02-06 16:40:15 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-02-09 16:51:42 -0800 |
| commit | 869176a096068056b338b5cc1b0af93106007f5d (patch) | |
| tree | e365ddc755b792a0b50fdf31e0b2e3081e40544d /include/linux | |
| parent | d76f99548cf0474c3bf75f25fab1778e03ade5f2 (diff) | |
| download | lwn-869176a096068056b338b5cc1b0af93106007f5d.tar.gz lwn-869176a096068056b338b5cc1b0af93106007f5d.zip | |
mm/vmalloc.c: add flags to mark vm_map_ram area
Through vmalloc API, a virtual kernel area is reserved for physical
address mapping. And vmap_area is used to track them, while vm_struct is
allocated to associate with the vmap_area to store more information and
passed out.
However, area reserved via vm_map_ram() is an exception. It doesn't have
vm_struct to associate with vmap_area. And we can't recognize the
vmap_area with '->vm == NULL' as a vm_map_ram() area because the normal
freeing path will set va->vm = NULL before unmapping, please see function
remove_vm_area().
Meanwhile, there are two kinds of handling for vm_map_ram area. One is
the whole vmap_area being reserved and mapped at one time through
vm_map_area() interface; the other is the whole vmap_area with
VMAP_BLOCK_SIZE size being reserved, while mapped into split regions with
smaller size via vb_alloc().
To mark the area reserved through vm_map_ram(), add flags field into
struct vmap_area. Bit 0 indicates this is vm_map_ram area created through
vm_map_ram() interface, while bit 1 marks out the type of vm_map_ram area
which makes use of vmap_block to manage split regions via vb_alloc/free().
This is a preparation for later use.
Link: https://lkml.kernel.org/r/20230206084020.174506-3-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/vmalloc.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h index 096d48aa3437..69250efa03d1 100644 --- a/include/linux/vmalloc.h +++ b/include/linux/vmalloc.h @@ -76,6 +76,7 @@ struct vmap_area { unsigned long subtree_max_size; /* in "free" tree */ struct vm_struct *vm; /* in "busy" tree */ }; + unsigned long flags; /* mark type of vm_map_ram area */ }; /* archs that select HAVE_ARCH_HUGE_VMAP should override one or more of these */ |