similar to: [PATCH 0/2] vhost, docs: convert to pin_user_pages(), new "case 5"

This is based on Linux 5.7, plus one prerequisite patch: "mm/gup: update pin_user_pages.rst for "case 3" (mmu notifiers)" [1] Changes since v1: removed references to set_page_dirty*(), in response to Souptick Joarder's review (thanks!). Cover letter for v1, edited/updated slightly: It recently became clear to me that there are some get_user_pages*() callers that

On Fri, May 29, 2020 at 04:43:08PM -0700, John Hubbard wrote: > +CASE 5: Pinning in order to write to the data within the page > +------------------------------------------------------------- > +Even though neither DMA nor Direct IO is involved, just a simple case of "pin, > +access page's data, unpin" can cause a problem. Case 5 may be considered a > +superset of Case

On Sat, May 30, 2020 at 5:13 AM John Hubbard <jhubbard at nvidia.com> wrote: > > There are four cases listed in pin_user_pages.rst. These are > intended to help developers figure out whether to use > get_user_pages*(), or pin_user_pages*(). However, the four cases > do not cover all the situations. For example, drivers/vhost/vhost.c > has a "pin, write to page, set

This code was using get_user_pages*(), in approximately a "Case 5" scenario (accessing the data within a page), using the categorization from [1]. That means that it's time to convert the get_user_pages*() + put_page() calls to pin_user_pages*() + unpin_user_pages() calls. There is some helpful background in [2]: basically, this is a small part of fixing a long-standing disconnect

There are four cases listed in pin_user_pages.rst. These are intended to help developers figure out whether to use get_user_pages*(), or pin_user_pages*(). However, the four cases do not cover all the situations. For example, drivers/vhost/vhost.c has a "pin, write to page, set page dirty, unpin" case. Add a fifth case, to help explain that there is a general pattern that requires

There are four cases listed in pin_user_pages.rst. These are intended to help developers figure out whether to use get_user_pages*(), or pin_user_pages*(). However, the four cases do not cover all the situations. For example, drivers/vhost/vhost.c has a "pin, write to page, set page dirty, unpin" case. Add a fifth case, to help explain that there is a general pattern that requires

From: John Hubbard <jhubbard at nvidia.com> Hi, This is mostly Jerome's work, converting the block/bio and related areas to call put_user_page*() instead of put_page(). Because I've changed Jerome's patches, in some cases significantly, I'd like to get his feedback before we actually leave him listed as the author (he might want to disown some or all of these). I added a

From: John Hubbard <jhubbard at nvidia.com> Hi, This is mostly Jerome's work, converting the block/bio and related areas to call put_user_page*() instead of put_page(). Because I've changed Jerome's patches, in some cases significantly, I'd like to get his feedback before we actually leave him listed as the author (he might want to disown some or all of these). I added a

Pinned pages are not properly accounted particularly when mapping error occurs on IOTLB update. Clean up dangling pinned pages for the error path. As the inflight pinned pages, specifically for memory region that strides across multiple chunks, would need more than one free page for book keeping and accounting. For simplicity, pin pages for all memory in the IOVA range in one go rather than have

Pinned pages are not properly accounted particularly when mapping error occurs on IOTLB update. Clean up dangling pinned pages for the error path. As the inflight pinned pages, specifically for memory region that strides across multiple chunks, would need more than one free page for book keeping and accounting. For simplicity, pin pages for all memory in the IOVA range in one go rather than have

On Mon, Feb 06, 2023 at 07:00:35AM +0000, Arseniy Krasnov wrote: >This adds main logic of MSG_ZEROCOPY flag processing for packet >creation. When this flag is set and user's iov iterator fits for >zerocopy transmission, call 'get_user_pages()' and add returned >pages to the newly created skb. > >Signed-off-by: Arseniy Krasnov <AVKrasnov at sberdevices.ru>

On 2020/10/30 ??3:45, Si-Wei Liu wrote: > This reverts commit 7ed9e3d97c32d969caded2dfb6e67c1a2cc5a0b1. > > Signed-off-by: Si-Wei Liu <si-wei.liu at oracle.com> > --- > drivers/vhost/vdpa.c | 119 +++++++++++++++++++++------------------------------ > 1 file changed, 48 insertions(+), 71 deletions(-) I saw this has been reverted there

From: "Michael S. Tsirkin" <mst at redhat.com> Date: Mon, 11 Mar 2019 09:59:28 -0400 > On Mon, Mar 11, 2019 at 03:13:17PM +0800, Jason Wang wrote: >> >> On 2019/3/8 ??10:12, Christoph Hellwig wrote: >> > On Wed, Mar 06, 2019 at 02:18:07AM -0500, Jason Wang wrote: >> > > This series tries to access virtqueue metadata through kernel virtual

From: "Michael S. Tsirkin" <mst at redhat.com> Date: Mon, 11 Mar 2019 09:59:28 -0400 > On Mon, Mar 11, 2019 at 03:13:17PM +0800, Jason Wang wrote: >> >> On 2019/3/8 ??10:12, Christoph Hellwig wrote: >> > On Wed, Mar 06, 2019 at 02:18:07AM -0500, Jason Wang wrote: >> > > This series tries to access virtqueue metadata through kernel virtual

We set dirty bit through setting up kmaps and access them through kernel virtual address, this may result alias in virtually tagged caches that require a dcache flush afterwards. Cc: Christoph Hellwig <hch at infradead.org> Cc: James Bottomley <James.Bottomley at HansenPartnership.com> Cc: Andrea Arcangeli <aarcange at redhat.com> Fixes: 3a4d5c94e9593 ("vhost_net: a

We set dirty bit through setting up kmaps and access them through kernel virtual address, this may result alias in virtually tagged caches that require a dcache flush afterwards. Cc: Christoph Hellwig <hch at infradead.org> Cc: James Bottomley <James.Bottomley at HansenPartnership.com> Cc: Andrea Arcangeli <aarcange at redhat.com> Fixes: 3a4d5c94e9593 ("vhost_net: a

From: John Hubbard <jhubbard at nvidia.com> In commit d241a95f3514 ("block: optionally mark pages dirty in bio_release_pages"), new "bool mark_dirty" argument was added to bio_release_pages. In upcoming work, another bool argument (to indicate that the pages came from get_user_pages) is going to be added. That's one bool too many, because it's not desirable have

On Wed, Feb 15, 2023 at 01:15:55PM +0800, Longpeng (Mike, Cloud Infrastructure Service Product Dept.) wrote: > > > ? 2023/2/15 10:56, Jason Wang ??: > > On Wed, Feb 15, 2023 at 10:49 AM Longpeng (Mike, Cloud Infrastructure > > Service Product Dept.) <longpeng2 at huawei.com> wrote: > > > > > > > > > > > > ? 2023/2/15 10:00, Jason

From: Martin Schwidefsky <schwidefsky@de.ibm.com> From: Hubertus Franke <frankeh@watson.ibm.com> From: Himanshu Raj <rhim@cc.gatech.edu> [patch 5/9] Guest page hinting: mlocked pages. Add code to get mlock() working with guest page hinting. The problem with mlock is that locked pages may not be removed from page cache. That means they need to be stable. page_make_volatile needs

From: Martin Schwidefsky <schwidefsky@de.ibm.com> From: Hubertus Franke <frankeh@watson.ibm.com> From: Himanshu Raj <rhim@cc.gatech.edu> [patch 5/9] Guest page hinting: mlocked pages. Add code to get mlock() working with guest page hinting. The problem with mlock is that locked pages may not be removed from page cache. That means they need to be stable. page_make_volatile needs