From: Matthew Wilcox <willy@infradead.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: akpm@linux-foundation.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, peterx@redhat.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 v6 4/6] mm: change folio_lock_or_retry to use vm_fault directly
Date: Fri, 30 Jun 2023 04:36:44 +0100 [thread overview]
Message-ID: <ZJ5NzJDY0XPt8ui1@casper.infradead.org> (raw)
In-Reply-To: <20230630020436.1066016-5-surenb@google.com>
On Thu, Jun 29, 2023 at 07:04:33PM -0700, Suren Baghdasaryan wrote:
> Change folio_lock_or_retry to accept vm_fault struct and return the
> vm_fault_t directly.
I thought we decided to call this folio_lock_fault()?
> +static inline vm_fault_t folio_lock_or_retry(struct folio *folio,
> + struct vm_fault *vmf)
> {
> might_sleep();
> - return folio_trylock(folio) || __folio_lock_or_retry(folio, mm, flags);
> + return folio_trylock(folio) ? 0 : __folio_lock_or_retry(folio, vmf);
No, don't use the awful ternary operator. The || form is used
everywhere else.
> /*
> * Return values:
> - * true - folio is locked; mmap_lock is still held.
> - * false - folio is not locked.
> + * 0 - folio is locked.
> + * VM_FAULT_RETRY - folio is not locked.
I don't think we want to be so prescriptive here. It returns non-zero
if the folio is not locked. The precise value is not something that
callers should depend on.
next prev parent reply other threads:[~2023-06-30 3:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-30 2:04 [PATCH v6 0/6] Per-VMA lock support for swap and userfaults Suren Baghdasaryan
2023-06-30 2:04 ` [PATCH v6 1/6] swap: remove remnants of polling from read_swap_cache_async Suren Baghdasaryan
2023-06-30 2:04 ` [PATCH v6 2/6] mm: add missing VM_FAULT_RESULT_TRACE name for VM_FAULT_COMPLETED Suren Baghdasaryan
2023-06-30 2:04 ` [PATCH v6 3/6] mm: drop per-VMA lock when returning VM_FAULT_RETRY or VM_FAULT_COMPLETED Suren Baghdasaryan
2023-06-30 2:04 ` [PATCH v6 4/6] mm: change folio_lock_or_retry to use vm_fault directly Suren Baghdasaryan
2023-06-30 3:36 ` Matthew Wilcox [this message]
2023-06-30 3:45 ` Suren Baghdasaryan
2023-06-30 3:47 ` Matthew Wilcox
2023-06-30 21:25 ` Suren Baghdasaryan
2023-06-30 2:04 ` [PATCH v6 5/6] mm: handle swap page faults under per-VMA lock Suren Baghdasaryan
2023-06-30 2:04 ` [PATCH v6 6/6] mm: handle userfaults under VMA lock Suren Baghdasaryan
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