linux-kernel - Re: [PATCH v3 2/5] vfio/type1: optimize vfio_pin_pages

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Message-ID: <20250708030017.46848-1-lizhe.67@bytedance.com>
Date: Tue,  8 Jul 2025 11:00:17 +0800
From: lizhe.67@...edance.com
To: david@...hat.com
Cc: akpm@...ux-foundation.org,
	alex.williamson@...hat.com,
	jgg@...pe.ca,
	kvm@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-mm@...ck.org,
	lizhe.67@...edance.com,
	peterx@...hat.com
Subject: Re: [PATCH v3 2/5] vfio/type1: optimize vfio_pin_pages_remote()

On Mon, 7 Jul 2025 09:29:30 +0200, david@...hat.com wrote:
 
> > @@ -680,32 +724,47 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
> >   		 * and rsvd here, and therefore continues to use the batch.
> >   		 */
> >   		while (true) {
> > +			long nr_pages, acct_pages = 0;
> > +
> >   			if (pfn != *pfn_base + pinned ||
> >   			    rsvd != is_invalid_reserved_pfn(pfn))
> >   				goto out;
> >   
> > +			/*
> > +			 * Using GUP with the FOLL_LONGTERM in
> > +			 * vaddr_get_pfns() will not return invalid
> > +			 * or reserved pages.
> > +			 */
> > +			nr_pages = num_pages_contiguous(
> > +					&batch->pages[batch->offset],
> > +					batch->size);
> > +			if (!rsvd) {
> > +				acct_pages = nr_pages;
> > +				acct_pages -= vpfn_pages(dma, iova, nr_pages);
> > +			}
> > +
> >   			/*
> >   			 * Reserved pages aren't counted against the user,
> >   			 * externally pinned pages are already counted against
> >   			 * the user.
> >   			 */
> > -			if (!rsvd && !vfio_find_vpfn(dma, iova)) {
> > +			if (acct_pages) {
> >   				if (!dma->lock_cap &&
> > -				    mm->locked_vm + lock_acct + 1 > limit) {
> > +						mm->locked_vm + lock_acct + acct_pages > limit) {
> 
> Weird indentation change.
> 
> It should be
> 
> if (!dma->lock_cap &&
>      mm->locked_vm + lock_acct + acct_pages > limit) {
> 
>      ^ aligned here

Thank you! We need the following fixup code.

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 03fce54e1372..6909275e46c2 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -750,7 +750,7 @@ static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
 			 */
 			if (acct_pages) {
 				if (!dma->lock_cap &&
-						mm->locked_vm + lock_acct + acct_pages > limit) {
+				     mm->locked_vm + lock_acct + acct_pages > limit) {
 					pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
 						__func__, limit << PAGE_SHIFT);
 					ret = -ENOMEM;


> Please don't drop acks/rbs already given in previous submissions.

Sorry for the inconvenience it may have caused.

> Acked-by: David Hildenbrand <david@...hat.com>

Thank you once again for your review.

Thanks,
Zhe