On Fri, Aug 18, 2023 at 05:08:44PM +0200, Thomas Hellström wrote:
> Account these pages against RLIMIT_MEMLOCK following how RDMA does this
> with CAP_IPC_LOCK bypassing the limit.
>
> Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Patch LGTM but nits on naming + possible assert.
> ---
> drivers/gpu/drm/xe/xe_vm.c | 43 ++++++++++++++++++++++++++++++++++++--
> 1 file changed, 41 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index ecbcad696b60..d9c000689002 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -34,6 +34,33 @@
>
> #define TEST_VM_ASYNC_OPS_ERROR
>
> +/*
> + * Perform userptr PIN accounting against RLIMIT_MEMLOCK for now, similarly
> + * to how RDMA does this.
> + */
> +static int xe_vma_mlock_alloc(struct xe_vma *vma, unsigned long num_pages)
> +{
xe_vma_userptr_mlock_alloc? or maybe even xe_vma_userptr_mlock_reserve?
> + unsigned long lock_limit, new_pinned;
> + struct mm_struct *mm = vma->userptr.notifier.mm;
> +
This be a candidate to use the new aseert macros to ensure that the vma
is a userptr + pinned? Not sure if that merged yet.
> + if (!can_do_mlock())
> + return -EPERM;
> +
> + lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
> + new_pinned = atomic64_add_return(num_pages, &mm->pinned_vm);
> + if (new_pinned > lock_limit && !capable(CAP_IPC_LOCK)) {
> + atomic64_sub(num_pages, &mm->pinned_vm);
> + return -ENOMEM;
> + }
> +
> + return 0;
> +}
> +
> +static void xe_vma_mlock_free(struct xe_vma *vma, unsigned long num_pages)
> +{
xe_vma_userptr_mlock_free? or maybe even xe_vma_userptr_mlock_release?
Same for the assert here.
Anyways, I'll leave addressing these nits up to you, with that:
Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx>
> + atomic64_sub(num_pages, &vma->userptr.notifier.mm->pinned_vm);
> +}
> +
> /**
> * xe_vma_userptr_check_repin() - Advisory check for repin needed
> * @vma: The userptr vma
> @@ -89,9 +116,17 @@ int xe_vma_userptr_pin_pages(struct xe_vma *vma)
> !read_only);
> pages = vma->userptr.pinned_pages;
> } else {
> + if (xe_vma_is_pinned(vma)) {
> + ret = xe_vma_mlock_alloc(vma, num_pages);
> + if (ret)
> + return ret;
> + }
> +
> pages = kvmalloc_array(num_pages, sizeof(*pages), GFP_KERNEL);
> - if (!pages)
> - return -ENOMEM;
> + if (!pages) {
> + ret = -ENOMEM;
> + goto out_account;
> + }
> }
>
> pinned = ret = 0;
> @@ -187,6 +222,9 @@ int xe_vma_userptr_pin_pages(struct xe_vma *vma)
> mm_closed:
> kvfree(pages);
> vma->userptr.pinned_pages = NULL;
> +out_account:
> + if (xe_vma_is_pinned(vma))
> + xe_vma_mlock_free(vma, num_pages);
> return ret;
> }
>
> @@ -1004,6 +1042,7 @@ static void xe_vma_destroy_late(struct xe_vma *vma)
> unpin_user_pages_dirty_lock(vma->userptr.pinned_pages,
> vma->userptr.num_pinned,
> !read_only);
> + xe_vma_mlock_free(vma, xe_vma_size(vma) >> PAGE_SHIFT);
> kvfree(vma->userptr.pinned_pages);
> }
>
> --
> 2.41.0
>
