From: Gregory Price <gregory.price@memverge.com>
To: Zhongkun He <hezhongkun.hzk@bytedance.com>
Cc: Vinicius Petrucci <vpetrucci@gmail.com>,
akpm@linux-foundation.org, linux-mm@vger.kernel.org,
linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-api@vger.kernel.org,
minchan@kernel.org, dave.hansen@linux.intel.com, x86@kernel.org,
Jonathan.Cameron@huawei.com, aneesh.kumar@linux.ibm.com,
ying.huang@intel.com, dan.j.williams@intel.com, fvdl@google.com,
surenb@google.com, rientjes@google.com, hannes@cmpxchg.org,
mhocko@suse.com, Hasan.Maruf@amd.com, jgroves@micron.com,
ravis.opensrc@micron.com, sthanneeru@micron.com,
emirakhur@micron.com, vtavarespetr@micron.com
Subject: Re: [RFC PATCH] mm/mbind: Introduce process_mbind() syscall for external memory binding
Date: Thu, 23 Nov 2023 16:42:32 -0500 [thread overview]
Message-ID: <ZV/HSFMmv3xwkNPL@memverge.com> (raw)
In-Reply-To: <CACSyD1OFjROw26+2ojG37eDBParVg721x1HCROMiF2pW2aHj8A@mail.gmail.com>
On Fri, Nov 24, 2023 at 04:13:41PM +0800, Zhongkun He wrote:
>
> Per my understanding, the process_mbind() is implementable without
> many difficult challenges，
> since it is always protected by mm->mmap_lock. But task mempolicy does
> not acquire any lock
> in alloc_pages().
per-vma policies are protected by the mmap lock, while the task
mempolicy is protected by the task lock on replacement, and
task->mems_allowed (protected by task_lock).
There is an update in my refactor tickets that enforces the acquisition
of task_lock on mpol_set_nodemask, which prevents the need for
alloc_pages to do anything else. That's not present in this patch.
Basically mems_allowed deals with the majority of situations, and
mmap_lock deals with per-vma mempolicy changes and migrations.
~Gregory
next prev parent reply other threads:[~2023-11-24 20:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-22 21:31 [RFC PATCH] mm/mbind: Introduce process_mbind() syscall for external memory binding Vinicius Petrucci
2023-11-22 21:39 ` Andrew Morton
2023-11-22 21:45 ` Gregory Price
2023-11-22 23:57 ` Vinicius Petrucci
2023-11-22 23:53 ` Gregory Price
2023-11-23 15:21 ` Vinicius Petrucci
2023-11-24 8:13 ` Zhongkun He
2023-11-23 21:42 ` Gregory Price [this message]
2023-11-30 9:34 ` Zhongkun He
2023-11-30 16:07 ` Gregory Price
2023-12-01 13:53 ` Zhongkun He
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