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Wed, 12 Apr 2023 21:35:33 +0900 (KST) Mime-Version: 1.0 Subject: RE: [PATCH v3] dma-buf/heaps: system_heap: avoid too much allocation Reply-To: jaewon31.kim@samsung.com Sender: Jaewon Kim From: Jaewon Kim To: Michal Hocko CC: "jstultz@google.com" , "tjmercier@google.com" , "sumit.semwal@linaro.org" , "daniel.vetter@ffwll.ch" , "akpm@linux-foundation.org" , "hannes@cmpxchg.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "jaewon31.kim@gmail.com" X-Priority: 3 X-Content-Kind-Code: NORMAL In-Reply-To: X-Drm-Type: N,general X-Msg-Generator: Mail X-Msg-Type: PERSONAL X-Reply-Demand: N Message-ID: <20230412123532epcms1p23092e51df04b3fb4e18e90b324ebcaa4@epcms1p2> Date: Wed, 12 Apr 2023 21:35:32 +0900 X-CMS-MailID: 20230412123532epcms1p23092e51df04b3fb4e18e90b324ebcaa4 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: SVC_REQ_APPROVE CMS-TYPE: 101P X-CPGSPASS: Y X-CPGSPASS: Y X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFtrKJsWRmVeSWpSXmKPExsWy7bCmnu7UpWYpBnv3a1vMWb+GzeLlIU2L hQ/vMlus3uRr0b15JqNF7/tXTBZ/Tmxks7i8aw6bxb01/1kt7vc5WJy6+5nd4t36L2wOPB6H 37xn9tj7bQGLx85Zd9k9Fmwq9dj0aRK7x51re9g8Tsz4zeLRt2UVo8f6LVdZPD5vkgvgisq2 yUhNTEktUkjNS85PycxLt1XyDo53jjc1MzDUNbS0MFdSyEvMTbVVcvEJ0HXLzAE6WkmhLDGn FCgUkFhcrKRvZ1OUX1qSqpCRX1xiq5RakJJTYFagV5yYW1yal66Xl1piZWhgYGQKVJiQnbHk wW22gs0cFS9fPGduYLzH1sXIySEhYCLR2HUJyObiEBLYwSix+etJpi5GDg5eAUGJvzuEQWqE Bfwl9r2YwwhiCwkoSZz9cYUdIq4r0dS9mgXEZhPQlni/YBIriC0CVNO1eSfYTGaBy8wSrVf3 QS3jlZjR/pQFwpaW2L58K9hQTgE9idnbHjNBxEUlbq5+yw5jvz82nxHCFpFovXeWGcIWlHjw czcjzJw/x59DzS+WWNb5AGpOjcSKc6ug4uYSDW9Xgtm8Ar4S1/Z9BjuURUBVYm/LdKh6F4lp 81eDzWQWkJfY/nYOMygcmAU0Jdbv0ocoUZTY+XsuVAmfxLuvPawwbzVs/M2Ojb1j3hOo8WoS Lc++QtXLSPz994x1AqPSLERIz0KyeBbC4gWMzKsYxVILinPTU4sNC0zhkZucn7uJEZx+tSx3 ME5/+0HvECMTB+MhRgkOZiUR3h8upilCvCmJlVWpRfnxRaU5qcWHGE2BXp7ILCWanA/MAHkl 8YYmlgYmZkYmFsaWxmZK4rxfnmqnCAmkJ5akZqemFqQWwfQxcXBKNTCtLRJWmpfdrHTv83uv z2+OX3dMeXl8m7bT1TtTWAwbwuPMzd9p/P90Y5F82QL5uT8PxXnwcT7UfLGuctvW4LbGpX2H /7z6LJ0r3HyHKWhvsaF+BofwHS9doycnF++LvrSmWfLGnIB1JZHqQpaGE0+vOnTg+RKHD377 vivHy944Ffh2wscuqfNTVq791cEf1ZV2NWJrb/bUfwt2+CRuPa+eGN9XtcT3xlfnPV2aBQsm 5a2ycDI6IGceVXFTfNevP3W2b9beOzpt7zSHtFP5YsqPfpzPPvPCPO1hVmjYm9CYuCmPa618 JHlVOjgdg29xX1/f4sg4T3tvS17N1ZuhFxKcL0Qzc+7deOXCFs8/O73vKrEUZyQaajEXFScC AE1cRVVIBAAA DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20230410073304epcas1p4cf3079b096994d69472b7801bd530bc7 References: <20230410073228.23043-1-jaewon31.kim@samsung.com> <20230412085726epcms1p7d2bec2526e47bd10a3b6ea6a113c9cc3@epcms1p7> <20230412094440epcms1p445319579ead0d0576bb616ebb07501b4@epcms1p4> <20230412113759epcms1p8cb15b54e3a96c7616419cb030d16f804@epcms1p8> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >On Wed 12-04-23 20:37:59, Jaewon Kim wrote: >> Limiting dmabuf memory may be required. But I think there >> is no nice and reasonable way so far. > >If that is really the way then the patch doesn't really add a big >benefit. It doesn't really prevent OOMs (or panics due to OOM) as the >allocator still allows to consume arbitrary amount of memory. The >provided check is not able to tell between buggy and legit calls. >-- >Michal Hocko >SUSE Labs Yes it could be. Though the buggy call is blocked by totalram_pages check, mm may suffer memory shortage due to the huge memory consumption through dma-buf system heap. We just hope Android LMKD or oomk kills the memory hoggers prior to oom panic. IMO if possible mm should be able to track the dma-buf size as stat in mm_rss_stat for each process. Then oomk is able to know size through get_mm_rss. Actually in mobile device environment, there is one more this kind of allocator. That is graphics drivers. They also consumes quite much memory and they may allocate as userspace wants. Jaewon Kim