From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2E067365A00; Fri, 24 Apr 2026 19:26:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777058780; cv=none; b=Tde4C81jeHGva5Ph60sYXFOUBgd1qklkWc3iFF86uqDDiYpRB2NcWhBXfnRlcye8YsYn2H1KQsbdNBeotLe0kxReIMsZUW1XgOm4Q+jvdE08/PWVKu/VgUYXzDWQ4wGvMiyDgKxx+hp8n/GtKWXZhCVhtFKi5Xm+s2OabfdNwD0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777058780; c=relaxed/simple; bh=DWkMRzIlP/FCulKUdiF1Fu9vzPWL2Yx2UPbG01OJWhY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=CVfs022DxZPj7JNSC2rNZvncUMlV8Ve8+gZ9JJL6xhTHEX2SMlG/CExI6UdhLHnvAhDojuS/aOY9w5IBxTTKoHtLQFhgqhVJipV3ThFUPOG2oniI9l/TW9kbuf96sz1ShJZpgOYpdEM/KUJ16PeYonhIvf5IcsMolNUeHfQ5U/I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m19PBkcH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="m19PBkcH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 536A8C19425; Fri, 24 Apr 2026 19:26:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777058779; bh=DWkMRzIlP/FCulKUdiF1Fu9vzPWL2Yx2UPbG01OJWhY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; 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> Precedence: bulk X-Mailing-List: linux-s390@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: 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/