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b=m19PBkcH3MjvyyP06bmauP0lmxSN/COgljVdoI+ldpXHQU0DtDimhU8PVacYX+Bo2 21pLVZGKSDmK0ObihtLemaCagvhphfyGcvLG/6WJEAkk9fBOQ9e/cAprEuiVcWRui4 hUD1BAa6CHaS2D9LcIcsRFxBUABxBro0F76eguF13ien5tNX2z1dhmTqPF4ZIzBCE5 2896KCE91Za+W4T5UgBiEvueRIAxp3U2Khr7RTsylHURbrTlDTFpVWUqkpzJQqvzSK x9FUsCN2m2mX21Yu6ULCN8e75VXFWFkBTqRI9G53rhkmG9/xN1kJBN4PXoUZcv2lix XPsYMFaNYOFiQ== Date: Fri, 24 Apr 2026 12:26:17 -0700 From: Minchan Kim To: Michal Hocko Cc: akpm@linux-foundation.org, hca@linux.ibm.com, linux-s390@vger.kernel.org, david@kernel.org, brauner@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, surenb@google.com, timmurray@google.com Subject: Re: [PATCH v1 2/3] mm: process_mrelease: skip LRU movement for exclusive file folios Message-ID: References: <20260421230239.172582-1-minchan@kernel.org> <20260421230239.172582-3-minchan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: bne6p5b1y6sf36qrod6co41nkgjgjnfx X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: D149CA000C X-Rspam-User: X-HE-Tag: 1777058780-652979 X-HE-Meta: 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 iuW0yZb/ Qk5N7VOubq1mWwkFurUSHRgeUOUR2batk00Ih3FS1i/FWL/iNVAp8XaRRD+WfJoAo4KaSiEy9BGx4LUhbLxmVF/Rqbh7UvlOYhqLgol9/g60SjC2m5y+jfg8rQ6Bm/edI3I5pm1kq2e2JAoKggc1qA6yFNCvAcz29OHXUjs6xeeEYB6+rWxWmFNhs9SjuxzYLvIZP/QwzAEPWUlENdewPLbdBX2XBc6yYO04FRImWEObTIGZYyDLnZ3lLYqtTM1AJgTQ4qTy080DKyL7obDZi7nCUWNPiaCULTlmhvUCPPSP5dH+7bd2XSu5Iqw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Apr 24, 2026 at 09:51:22AM +0200, Michal Hocko wrote: > On Tue 21-04-26 16:02:38, Minchan Kim wrote: > > For the process_mrelease reclaim, skip LRU handling for exclusive > > file-backed folios since they will be freed soon so pointless > > to move around in the LRU. > > > > This avoids costly LRU movement which accounts for a significant portion > > of the time during unmap_page_range. > > > > - 91.31% 0.00% mmap_exit_test [kernel.kallsyms] [.] exit_mm > > exit_mm > > __mmput > > exit_mmap > > unmap_vmas > > - unmap_page_range > > - 55.75% folio_mark_accessed > > + 48.79% __folio_batch_add_and_move > > 4.23% workingset_activation > > + 12.94% folio_remove_rmap_ptes > > + 9.86% page_table_check_clear > > + 3.34% tlb_flush_mmu > > 1.06% __page_table_check_pte_clear > > > > Signed-off-by: Minchan Kim > > As pointed out in the previous version of the patch. I really dislike > this to be mrelease or OOM specific. Behavior. You do not explain why > this needs to be this way, except for the performance reasons. My main > question is still unanswered (and NAK before this is sorted out). Why > this cannot be applied in general for _any_ exiting task. As you argue > the memory will just likely go away so why to bother? I revised the description to explain why I wanted to go with only specific, not in general. https://lore.kernel.org/linux-mm/aevBRh08X4UTMUj9@google.com/