From: Peter Xu <peterx@redhat.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: akpm@linux-foundation.org, willy@infradead.org,
hannes@cmpxchg.org, mhocko@suse.com, josef@toxicpanda.com,
jack@suse.cz, ldufour@linux.ibm.com, laurent.dufour@fr.ibm.com,
michel@lespinasse.org, liam.howlett@oracle.com,
jglisse@google.com, vbabka@suse.cz, minchan@google.com,
dave@stgolabs.net, punit.agrawal@bytedance.com,
lstoakes@gmail.com, hdanton@sina.com, apopple@nvidia.com,
ying.huang@intel.com, david@redhat.com, yuzhao@google.com,
dhowells@redhat.com, hughd@google.com, viro@zeniv.linux.org.uk,
brauner@kernel.org, pasha.tatashin@soleen.com,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH v2 4/6] mm: drop VMA lock before waiting for migration
Date: Fri, 9 Jun 2023 16:42:00 -0400 [thread overview]
Message-ID: <ZIOOmC26qh4EXUEX@x1n> (raw)
In-Reply-To: <20230609005158.2421285-5-surenb@google.com>
On Thu, Jun 08, 2023 at 05:51:56PM -0700, Suren Baghdasaryan wrote:
> migration_entry_wait does not need VMA lock, therefore it can be dropped
> before waiting. Introduce VM_FAULT_VMA_UNLOCKED to indicate that VMA
> lock was dropped while in handle_mm_fault().
> Note that once VMA lock is dropped, the VMA reference can't be used as
> there are no guarantees it was not freed.
Then vma lock behaves differently from mmap read lock, am I right? Can we
still make them match on behaviors, or there's reason not to do so?
One reason is if they match they can reuse existing flags and there'll be
less confusing, e.g. this:
(fault->flags & FAULT_FLAG_VMA_LOCK) &&
(vm_fault_ret && (VM_FAULT_RETRY || VM_FAULT_COMPLETE))
can replace the new flag, iiuc.
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2023-06-09 20:42 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-09 0:51 [PATCH v2 0/6] Per-vma lock support for swap and userfaults Suren Baghdasaryan
2023-06-09 0:51 ` [PATCH v2 1/6] swap: remove remnants of polling from read_swap_cache_async Suren Baghdasaryan
2023-06-09 1:57 ` Huang, Ying
2023-06-09 3:13 ` Ming Lei
2023-06-09 18:50 ` Suren Baghdasaryan
2023-06-12 4:53 ` Christoph Hellwig
2023-06-09 0:51 ` [PATCH v2 2/6] mm: handle swap page faults under VMA lock if page is uncontended Suren Baghdasaryan
2023-06-09 20:25 ` Peter Xu
2023-06-09 20:35 ` Matthew Wilcox
2023-06-09 20:45 ` Peter Xu
2023-06-09 22:34 ` Suren Baghdasaryan
2023-06-12 13:59 ` Peter Xu
2023-06-12 16:09 ` Suren Baghdasaryan
2023-06-09 0:51 ` [PATCH v2 3/6] mm: add missing VM_FAULT_RESULT_TRACE name for VM_FAULT_COMPLETED Suren Baghdasaryan
2023-06-09 20:34 ` Peter Xu
2023-06-09 0:51 ` [PATCH v2 4/6] mm: drop VMA lock before waiting for migration Suren Baghdasaryan
2023-06-09 20:42 ` Peter Xu [this message]
2023-06-09 22:30 ` Suren Baghdasaryan
2023-06-10 1:29 ` Suren Baghdasaryan
2023-06-12 13:36 ` Peter Xu
2023-06-12 16:07 ` Suren Baghdasaryan
2023-06-12 18:34 ` Peter Xu
2023-06-12 18:44 ` Suren Baghdasaryan
2023-06-12 18:57 ` Peter Xu
2023-06-12 13:28 ` Peter Xu
2023-06-12 15:41 ` Suren Baghdasaryan
2023-06-09 0:51 ` [PATCH v2 5/6] mm: implement folio wait under VMA lock Suren Baghdasaryan
2023-06-09 15:03 ` Matthew Wilcox
2023-06-09 18:49 ` Suren Baghdasaryan
2023-06-09 18:55 ` Suren Baghdasaryan
2023-06-09 19:36 ` Matthew Wilcox
2023-06-09 22:49 ` Suren Baghdasaryan
2023-06-09 20:54 ` Peter Xu
2023-06-09 22:48 ` Suren Baghdasaryan
2023-06-12 13:56 ` Peter Xu
2023-06-09 0:51 ` [PATCH v2 6/6] mm: handle userfaults " Suren Baghdasaryan
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