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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <3d0f189b-faab-4452-b9cc-8f4e7a15025f@linux.alibaba.com> <1179320d-6bab-40a4-a7ac-dbcfbab24623@linux.alibaba.com> <70ed2de7-3e66-4a23-85bb-e0a4c5b61088@linux.alibaba.com> From: Baolin Wang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 3D0DBC0005 X-Stat-Signature: 8bueuo9345f6qb9r5j1cgztcnxrij547 X-HE-Tag: 1770718082-222386 X-HE-Meta: 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 CzcEvx4l RK+uxFkeg254qxE4/S8o7D/zwf16S4mPncQnin7H4KFSjlyvzJs0nzPRIllZkd8eHYYaYGzCnWeiLL+6HxwJmL3lWo5FGIywnNff5AzsuORgdD64+oJVArjTSF/Fa+975YEdRyVnqmIshJUO41leGIAxYRWK5/JOED2yIow3DISXaPMHQV/mQ2AmpRcxxH3jYWQekGnLaFzsT3pVm1Wx287JUS7Gz7NQTuQcwds0HGAlCNGAnw39mHRV6vxHCriJPQzz5g1FOKLah34qk6VViz7rTqLqVKT9nI2Xd7+FUDSwjMUWWZKhalgyjo4Ac/YY6oTqxvEpatUX+DbESjolNvwlcKKY081iF+VwJ1TbaYk1uN4+dMWLdnr/CUw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/10/26 11:21 AM, Sergey Senozhatsky wrote: > On (26/02/06 10:00), David Hildenbrand (Arm) wrote: >>>> I recall that there is a notifier when the system is preparing to >>>> sleep (pm notifier or something). Could we simply hook into that to >>>> tell khugepaged to suspend+resume? >>> >>> Do you mean “struct dev_pm_ops”, which is used to register PM callbacks >>> for devices? However, I don’t know how to use it with a kernel thread. >>> >>> Also look at how kswapd does it, kswapd also uses >>> kthread_freezable_should_stop() to check the freeze state. >> >> Right, mimicking what kswapd does sound reasonable! > > I may be missing something, as I'm not seeing dev_pm_ops in vmscan code. > Would something like this work? > > --- > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index fa6a018b20a8..c5d89ec223d3 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -394,8 +394,12 @@ static inline int hpage_collapse_test_exit(struct mm_struct *mm) > > static inline int hpage_collapse_test_exit_or_disable(struct mm_struct *mm) > { > + bool was_frozen; > + int ret = kthread_freezable_should_stop(&was_frozen); > + > return hpage_collapse_test_exit(mm) || > - mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm); > + mm_flags_test(MMF_DISABLE_THP_COMPLETELY, mm) || > + was_frozen || ret; > } Since the hpage_collapse_test_exit_or_disable() can be called by madvise_callapse(), which is not a kernel thread. So I think using the try_to_freeze() is enough? or pass the cc->is_khugepaged to check if current thread is khugepaged.