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Mon, 1 Jun 2026 15:58:09 +0000 (GMT) Date: Mon, 1 Jun 2026 17:58:08 +0200 From: Alexander Gordeev To: Andrew Morton , Gerald Schaefer Cc: Nico Pache , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, aarcange@redhat.com, anshuman.khandual@arm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, catalin.marinas@arm.com, cl@gentwo.org, corbet@lwn.net, dave.hansen@linux.intel.com, david@kernel.org, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jack@suse.cz, jackmanb@google.com, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, liam@infradead.org, ljs@kernel.org, mathieu.desnoyers@efficios.com, matthew.brost@intel.com, mhiramat@kernel.org, mhocko@suse.com, peterx@redhat.com, pfalcato@suse.de, rakie.kim@sk.com, raquini@redhat.com, rdunlap@infradead.org, richard.weiyang@gmail.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, ryan.roberts@arm.com, shivankg@amd.com, sunnanyong@huawei.com, surenb@google.com, thomas.hellstrom@linux.intel.com, tiwai@suse.de, usamaarif642@gmail.com, vbabka@suse.cz, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, will@kernel.org, willy@infradead.org, yang@os.amperecomputing.com, ying.huang@linux.alibaba.com, ziy@nvidia.com, zokeefe@google.com, linux-s390@vger.kernel.org, linux-next@vger.kernel.org Subject: Re: [PATCH mm-hotfixes-unstable v18 00/14] khugepaged: add mTHP collapse support Message-ID: <20260601155808.2755103A59-agordeev@linux.ibm.com> References: <20260522150009.121603-1-npache@redhat.com> <20260522134724.f4f11941a85ef18b307d16ae@linux-foundation.org> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260522134724.f4f11941a85ef18b307d16ae@linux-foundation.org> X-TM-AS-GCONF: 00 X-Proofpoint-GUID: nfwYDs9TcjCv1m5SD5Q2yxQgbgrtXAhC X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjAxMDE1NiBTYWx0ZWRfXyLYMZqvlBwmh FIBRb5tIWjWqfgO88TmAAfsO9qJCH2UQwFruqUM2DQZBhQbobvvub4gPHV1p0z/SprglZkt6gtI 0ZEF7AzWNA9ysO0OSentgtCFSwU0Un2rFtOGyM+K1rqIkikhyLFyyZlMTviw6/Zg9EcDnW7V7/S G55DaMhAz6x7AwyHrk+c/RIHNV6UHt48a2t2XkLJrXBtkV6zE47lbWpx890raV5NiBCi4qKcoPm dQjA8ZvyVhdhV+MTZgejzg3iX5UEsawV2oi0yISpbc5myMiWvU5T/mvzb7itDe2zHSOM/a74Won Q5udMQxXvQdazyql+2jTgVazntIUYbNA4cIG6cFUdyyIjShE2MpYpdgTLRQAAOxKpQ8JvHPD+Va P4oKM1LpyU0RLzhy2HWRO8jGU3jl9ArFxP6Wzpe3+CpKC0Lq1YEuZ0+91gxoGiLvrlP9AfHV9Gi NXy5vwkdCVghclNBSBg== X-Proofpoint-ORIG-GUID: nfwYDs9TcjCv1m5SD5Q2yxQgbgrtXAhC X-Authority-Analysis: v=2.4 cv=Vf3H+lp9 c=1 sm=1 tr=0 ts=6a1dac15 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=kj9zAlcOel0A:10 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=20KFwNOVAAAA:8 a=0zv6X75myPOFEK8-PwYA:9 a=CjuIK1q_8ugA:10 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-01_04,2026-05-28_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 suspectscore=0 adultscore=0 bulkscore=0 impostorscore=0 phishscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1011 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2605210000 definitions=main-2606010156 On Fri, May 22, 2026 at 01:47:24PM -0700, Andrew Morton wrote: Hi Andrew et al, > On Fri, 22 May 2026 08:59:55 -0600 Nico Pache wrote: > > > The following series provides khugepaged with the capability to collapse > > anonymous memory regions to mTHPs. > > Thanks, I've update mm.git's mm-unstable branch to this version. > > It sounds like I might be dropping it soon, haven't started looking at > that yet. But let's at least eyeball the latest version at this time. > > Sashiko was able to apply this, so the base-it-on-hotfixes thing worked > well, thanks. The AI checking made a few allegations: This series appears to cause hangs on s390 in linux-next. The issue is not easily reproducible, so it is not yet confirmed. Any ideas for a reliable reproducer that exercises the code path below? [ 2749.385719] sysrq: Show Blocked State [ 2749.385730] task:khugepaged state:D stack:0 pid:209 tgid:209 ppid:2 task_flags:0x200040 flags:0x00000000 [ 2749.385735] Call Trace: [ 2749.385736] [<0000017f63c8b226>] __schedule+0x316/0x890 [ 2749.385740] [<0000017f63c8b7dc>] schedule+0x3c/0xc0 [ 2749.385743] [<0000017f63c8b888>] schedule_preempt_disabled+0x28/0x40 [ 2749.385746] [<0000017f63c902ea>] rwsem_down_write_slowpath+0x2fa/0x8b0 [ 2749.385749] [<0000017f63c90910>] down_write+0x70/0x80 [ 2749.385752] [<0000017f6313407a>] collapse_huge_page+0x2ea/0x9e0 [ 2749.385755] [<0000017f6313491e>] mthp_collapse+0x1ae/0x1f0 [ 2749.385757] [<0000017f63134fda>] collapse_scan_pmd+0x67a/0x8f0 [ 2749.385760] [<0000017f6313751a>] collapse_single_pmd+0x15a/0x260 [ 2749.385762] [<0000017f6313792c>] collapse_scan_mm_slot.constprop.0+0x30c/0x470 [ 2749.385765] [<0000017f63137cb6>] khugepaged+0x226/0x240 [ 2749.385768] [<0000017f62db3128>] kthread+0x148/0x170 [ 2749.385770] [<0000017f62d2c238>] __ret_from_fork+0x48/0x220 [ 2749.385772] [<0000017f63c95d0a>] ret_from_fork+0xa/0x30 Thanks!