The patch titled
Subject: zsmalloc: switch from alloc_vm_area to get_vm_area
has been added to the -mm tree. Its filename is
zsmalloc-switch-from-alloc_vm_area-to-get_vm_area.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/zsmalloc-switch-from-alloc_vm_area-to-get_vm_area.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/zsmalloc-switch-from-alloc_vm_area-to-get_vm_area.patch
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------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: zsmalloc: switch from alloc_vm_area to get_vm_area
Just manually pre-fault the PTEs using apply_to_page_range.
Link: https://lkml.kernel.org/r/20200930175133.1252382-6-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Co-developed-by: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Matthew Auld <matthew.auld@xxxxxxxxx>
Cc: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Cc: Nitin Gupta <ngupta@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/zsmalloc.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/mm/zsmalloc.c~zsmalloc-switch-from-alloc_vm_area-to-get_vm_area
+++ a/mm/zsmalloc.c
@@ -1122,10 +1122,16 @@ static inline int __zs_cpu_up(struct map
*/
if (area->vm)
return 0;
- area->vm = alloc_vm_area(PAGE_SIZE * 2, NULL);
+ area->vm = get_vm_area(PAGE_SIZE * 2, 0);
if (!area->vm)
return -ENOMEM;
- return 0;
+
+ /*
+ * Populate ptes in advance to avoid pte allocation with GFP_KERNEL
+ * in non-preemtible context of zs_map_object.
+ */
+ return apply_to_page_range(&init_mm, (unsigned long)area->vm->addr,
+ PAGE_SIZE * 2, NULL, NULL);
}
static inline void __zs_cpu_down(struct mapping_area *area)
_
Patches currently in -mm which might be from hch@xxxxxx are
mm-add-a-vm_map_put_pages-flag-for-vmap.patch
mm-add-a-vmap_pfn-function.patch
mm-allow-a-null-fn-callback-in-apply_to_page_range.patch
zsmalloc-switch-from-alloc_vm_area-to-get_vm_area.patch
drm-i915-use-vmap-in-shmem_pin_map.patch
drm-i915-use-vmap-in-i915_gem_object_map.patch
xen-xenbus-use-apply_to_page_range-directly-in-xenbus_map_ring_pv.patch
x86-xen-open-code-alloc_vm_area-in-arch_gnttab_valloc.patch
mm-remove-alloc_vm_area.patch
