Re: [v2 PATCH 1/2] mm: gup: fix the fast GUP race against THP collapse

2022-09-07 Thread John Hubbard
On 9/7/22 11:01, Yang Shi wrote: Since general RCU GUP fast was introduced in commit 2667f50e8b81 ("mm: introduce a general RCU get_user_pages_fast()"), a TLB flush is no longer sufficient to handle concurrent GUP-fast in all cases, it only handles traditional IPI-based GUP-fast correctly. On

Re: [v2 PATCH 1/2] mm: gup: fix the fast GUP race against THP collapse

2022-09-07 Thread Yang Shi
On Wed, Sep 7, 2022 at 2:22 PM Andrew Morton wrote: > > On Wed, 7 Sep 2022 11:01:43 -0700 Yang Shi wrote: > > > Since general RCU GUP fast was introduced in commit 2667f50e8b81 ("mm: > > introduce a general RCU get_user_pages_fast()"), a TLB flush is no longer > > sufficient to handle

Re: [v2 PATCH 1/2] mm: gup: fix the fast GUP race against THP collapse

2022-09-07 Thread Andrew Morton
On Wed, 7 Sep 2022 11:01:43 -0700 Yang Shi wrote: > Since general RCU GUP fast was introduced in commit 2667f50e8b81 ("mm: > introduce a general RCU get_user_pages_fast()"), a TLB flush is no longer > sufficient to handle concurrent GUP-fast in all cases, it only handles > traditional IPI-based

[v2 PATCH 1/2] mm: gup: fix the fast GUP race against THP collapse

2022-09-07 Thread Yang Shi
Since general RCU GUP fast was introduced in commit 2667f50e8b81 ("mm: introduce a general RCU get_user_pages_fast()"), a TLB flush is no longer sufficient to handle concurrent GUP-fast in all cases, it only handles traditional IPI-based GUP-fast correctly. On architectures that send an IPI