Jason Gunthorpe jgg@nvidia.com writes:
On Tue, Jan 24, 2023 at 04:42:30PM +1100, Alistair Popple wrote:
+/**
- enum vm_account_flags - Determine how pinned/locked memory is accounted.
- @VM_ACCOUNT_TASK: Account pinned memory to mm->pinned_vm.
- @VM_ACCOUNT_BYPASS: Don't enforce rlimit on any charges.
- @VM_ACCOUNT_USER: Accounnt locked memory to user->locked_vm.
- Determines which statistic pinned/locked memory is accounted
- against. All limits will be enforced against RLIMIT_MEMLOCK and the
- pins cgroup if CONFIG_CGROUP_PINS is enabled.
- New drivers should use VM_ACCOUNT_TASK. VM_ACCOUNT_USER is used by
- pre-existing drivers to maintain existing accounting against
- user->locked_mm rather than mm->pinned_mm.
I thought the guidance was the opposite of this, it is the newer places in the kernel that are using VM_ACCOUNT_USER?
I'd just assumed mm->pinned_vm was preferred because that's what most drivers use. user->locked_mm does seem more sensible though as at least it's possible to meaningfully enforce some overall limit. Will switch the flags/comment around to suggest new users use VM_ACCOUNT_USER.
I haven't got to the rest of the patches yet, but isn't there also a mm->pinned_vm vs mm->locked_vm variation in the current drivers as well?
+void vm_account_init_current(struct vm_account *vm_account) +{
- vm_account_init(vm_account, current, NULL, VM_ACCOUNT_TASK);
+} +EXPORT_SYMBOL_GPL(vm_account_init_current);
This can probably just be a static inline
You might consider putting all this in some new vm_account.h - given how rarely it is used? Compile times and all
Works for me.
Jason