From: "Yang, Philip" <Philip.Yang@amd.com>
To: Jason Gunthorpe <jgg@mellanox.com>,
Ralph Campbell <rcampbell@nvidia.com>
Cc: "jglisse@redhat.com" <jglisse@redhat.com>,
"alex.deucher@amd.com" <alex.deucher@amd.com>,
"amd-gfx@lists.freedesktop.org" <amd-gfx@lists.freedesktop.org>,
"Kuehling, Felix" <Felix.Kuehling@amd.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH] mm/hmm: hmm_range_fault handle pages swapped out
Date: Fri, 16 Aug 2019 16:02:30 +0000 [thread overview]
Message-ID: <6a694960-51c8-532c-6dfd-f3479d680510@amd.com> (raw)
In-Reply-To: <20190816005429.GD9929@mellanox.com>
On 2019-08-15 8:54 p.m., Jason Gunthorpe wrote:
> On Thu, Aug 15, 2019 at 08:52:56PM +0000, Yang, Philip wrote:
>> hmm_range_fault may return NULL pages because some of pfns are equal to
>> HMM_PFN_NONE. This happens randomly under memory pressure. The reason is
>> for swapped out page pte path, hmm_vma_handle_pte doesn't update fault
>> variable from cpu_flags, so it failed to call hmm_vam_do_fault to swap
>> the page in.
>>
>> The fix is to call hmm_pte_need_fault to update fault variable.
>
>> Change-Id: I2e8611485563d11d938881c18b7935fa1e7c91ee
>
> I'll fix it for you but please be careful not to send Change-id's to
> the public lists.
>
Thanks, the change-id was added by our Gerrit hook, I need generate
patch files, remove change-id line and then send out modified patch
files in future.
> Also what is the Fixes line for this?
>
This fixes the issue found by the internal rocrtst, the
rocrtstFunc.Memory_Max_Mem evicted some user buffers, and then following
test restore those user buffers failed because the buffers are swapped
out and application doesn't touch the buffers to swap it in.
>> Signed-off-by: Philip Yang <Philip.Yang@amd.com>
>> mm/hmm.c | 3 +++
>> 1 file changed, 3 insertions(+)
>
> Ralph has also been looking at this area also so I'll give him a bit
> to chime in, otherwise with Jerome's review this looks OK to go to
> linux-next
>
Ok, thanks for helping push this to hmm branch at
https://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma.git
> Thanks,
> Jason
>
next prev parent reply other threads:[~2019-08-16 16:02 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-15 20:52 [PATCH] mm/hmm: hmm_range_fault handle pages swapped out Yang, Philip
2019-08-15 21:02 ` Jerome Glisse
2019-08-16 0:54 ` Jason Gunthorpe
2019-08-16 16:02 ` Yang, Philip [this message]
2019-08-23 13:39 ` Jason Gunthorpe
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