From: Thomas Gleixner <tglx@linutronix.de>
To: "Reshetova, Elena" <elena.reshetova@intel.com>
Cc: "mingo@redhat.com" <mingo@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"viro@zeniv.linux.org.uk" <viro@zeniv.linux.org.uk>,
"tj@kernel.org" <tj@kernel.org>,
"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
"lizefan@huawei.com" <lizefan@huawei.com>,
"acme@kernel.org" <acme@kernel.org>,
"alexander.shishkin@linux.intel.com"
<alexander.shishkin@linux.intel.com>,
"eparis@redhat.com" <eparis@redhat.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"arnd@arndb.de" <arnd@arndb.de>,
"luto@kernel.org" <luto@kernel.org>,
"keescook@chromium.org" <keescook@chromium.org>,
"dvhart@infradead.org" <dvhart@infradead.org>,
"ebiederm@xmission.com" <ebiederm@xmission.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"axboe@kernel.dk" <axboe@kernel.dk>
Subject: RE: [PATCH 01/15] sched: convert sighand_struct.count to refcount_t
Date: Mon, 23 Oct 2017 12:26:47 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1710231223450.4241@nanos> (raw)
In-Reply-To: <2236FBA76BA1254E88B949DDB74E612B802B4359@IRSMSX102.ger.corp.intel.com>
On Mon, 23 Oct 2017, Reshetova, Elena wrote:
> > On Fri, 20 Oct 2017, Elena Reshetova wrote:
> > How did you make sure that these atomic operations have no other
> > serialization effect and can be replaced with refcount?
>
> What serialization effects? Are you taking about smth else than memory
> ordering?
Well, the memory ordering constraints can be part of serialization
mechanisms. Unfortunately they are not well documented ....
> For memory ordering my current hope is that we can just make refcount_t
> to use same strict atomic primitives and then it would not make any
> difference. I think this would be the simplest way for everyone since I
> think even some maintainers are having issues understanding all the
> implications of "relaxed" ordering.
Well, that would make indeed the conversion simpler because then it is just
a drop in replacement. Albeit there might be some places which benefit of
the relaxed ordering as on some architectures strict ordering is expensive.
Thanks,
tglx
next prev parent reply other threads:[~2017-10-23 10:26 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-20 12:15 [PATCH 00/15] v5 kernel core pieces refcount conversions Elena Reshetova
2017-10-20 12:15 ` [PATCH 01/15] sched: convert sighand_struct.count to refcount_t Elena Reshetova
2017-10-20 12:43 ` Thomas Gleixner
2017-10-23 10:22 ` Reshetova, Elena
2017-10-23 10:26 ` Thomas Gleixner [this message]
2017-10-23 10:45 ` Reshetova, Elena
2017-10-20 12:15 ` [PATCH 02/15] sched: convert signal_struct.sigcnt " Elena Reshetova
2017-10-20 12:15 ` [PATCH 03/15] sched: convert user_struct.__count " Elena Reshetova
2017-10-20 12:15 ` [PATCH 04/15] sched: convert numa_group.refcount " Elena Reshetova
2017-10-20 12:15 ` [PATCH 05/15] sched/task_struct: convert task_struct.usage " Elena Reshetova
2017-10-20 12:15 ` [PATCH 06/15] sched/task_struct: convert task_struct.stack_refcount " Elena Reshetova
2017-10-20 12:15 ` [PATCH 07/15] perf: convert perf_event_context.refcount " Elena Reshetova
2017-10-20 12:15 ` [PATCH 08/15] perf/ring_buffer: convert ring_buffer.refcount " Elena Reshetova
2017-10-20 12:15 ` [PATCH 09/15] perf/ring_buffer: convert ring_buffer.aux_refcount " Elena Reshetova
2017-10-20 12:15 ` [PATCH 10/15] uprobes: convert uprobe.ref " Elena Reshetova
2017-10-20 12:15 ` [PATCH 11/15] nsproxy: convert nsproxy.count " Elena Reshetova
2017-10-20 12:15 ` [PATCH 12/15] groups: convert group_info.usage " Elena Reshetova
2017-10-20 12:15 ` [PATCH 13/15] creds: convert cred.usage " Elena Reshetova
2017-10-20 12:15 ` [PATCH 14/15] kcov: convert kcov.refcount " Elena Reshetova
2017-10-20 12:15 ` [PATCH 15/15] bdi: convert bdi_writeback_congested.refcnt from atomic_t " Elena Reshetova
-- strict thread matches above, loose matches on Subject: below --
2017-08-30 12:22 [PATCH 00/15] v5 kernel core pieces refcount conversions Elena Reshetova
2017-08-30 12:22 ` [PATCH 01/15] sched: convert sighand_struct.count to refcount_t Elena Reshetova
2017-08-25 9:41 [PATCH 00/15] v4 kernel core pieces refcount conversions Elena Reshetova
2017-08-25 9:41 ` [PATCH 01/15] sched: convert sighand_struct.count to refcount_t Elena Reshetova
2017-07-18 10:29 [PATCH 00/15] v4 kernel core pieces refcount conversions Elena Reshetova
2017-07-18 10:29 ` [PATCH 01/15] sched: convert sighand_struct.count to refcount_t Elena Reshetova
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