Received: by 2002:a05:7208:9594:b0:7e:5202:c8b4 with SMTP id gs20csp2317109rbb; Tue, 27 Feb 2024 19:27:08 -0800 (PST) X-Forwarded-Encrypted: i=3; AJvYcCXVlf9gHN6QqtklOqOMt5FvTVCjlzSu0nlXjlInoHx8fvcFg2qw2CNRNu9dZFoh+Uq+HduSKJ3PqPBlklbJ6VI9qlGwY2pfpGfXrZ1fBw== X-Google-Smtp-Source: AGHT+IGkVHL8/AcEtLjgjUInzzUfywGiKzsM2cB4dL5ampyAbj3brCk3zzZemB+pDgv3AKWZzuct X-Received: by 2002:aa7:d841:0:b0:566:f60:4fc4 with SMTP id f1-20020aa7d841000000b005660f604fc4mr4601405eds.37.1709090828249; Tue, 27 Feb 2024 19:27:08 -0800 (PST) ARC-Seal: i=2; a=rsa-sha256; t=1709090828; cv=pass; d=google.com; s=arc-20160816; b=XBZxQTjVXVKxHVQ1EHAIAschDpGISamDCA2zMtOXq90JHZD9txNBEcQ3KKA92qZctZ OkcGr2mSdU0RSHouzAY8PLVQpMwnOOqjYol/k4E338AFBjplliHKB/Wdi16Qk5bJm9gY 7N+VxJ6Kcyb8D10pOrOCxg66XL4QLl9nYjBi9aI2VORjpNVT/P1+lWNv/u6Ijo/jTXQE 6cEEauIQifMYbOcjXRMUa5f9U9GSHaysA6+HzBFyV3KiVM/at4i7dPehK8w4L9FR4HF+ YAtI6iLq0SUZ4NhNm1U98/8rDNOpNjK0BXJ+LTyOg9nxA13rXXFWAiWiMNCF4tCrgsC6 EL9g== ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=in-reply-to:content-disposition:mime-version:list-unsubscribe :list-subscribe:list-id:precedence:references:message-id:subject:cc :to:from:date:dkim-signature; bh=xfBHH2R+HpI9h6VdbpXXPvs6htYiUptEJQWxbn/nS7o=; fh=hJx6WoY2VXffvj02iWHoehz9PG8JMnOYAXPiAVk+zhU=; b=i2UeQSC5Hdfa3btYE8QUHILzh4VMr2mXjkcSA32BdUVin3YF1rW73XuGqxaySp6Xn5 71y+v+CGgZrElQvGvGS98qDUxM/f9z0OpbYO8qsJ6sqQ+H53Hv/dttuG3f/WDsAN9B5n l9jkTl+RTD3TNy4Z4v/2fbQjd68w4EV3uqOLS2+jONrRe2AB5MLOYFyMwTFLk4DgZH4x NJYcPXotMW4HWbPomNDFm6OMQzZq8EYV6o6Zwc0YKLIjIMry5N43vg1BsFcqJWTd0wZr DvAKUt3glnsleF6QfL+qMXqgrJE4OWMoTIPkKIaQ9Dgr1ZLtzVzscF+uNf43Cs1fQrjk jcHQ==; dara=google.com ARC-Authentication-Results: i=2; mx.google.com; dkim=pass header.i=@chromium.org header.s=google header.b=dmfOanEO; arc=pass (i=1 spf=pass spfdomain=chromium.org dkim=pass dkdomain=chromium.org dmarc=pass fromdomain=chromium.org); spf=pass (google.com: domain of linux-kernel+bounces-84474-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) smtp.mailfrom="linux-kernel+bounces-84474-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=chromium.org Return-Path: Received: from am.mirrors.kernel.org (am.mirrors.kernel.org. [147.75.80.249]) by mx.google.com with ESMTPS id dc9-20020a056402310900b00565bb5a945dsi1240249edb.171.2024.02.27.19.27.08 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Feb 2024 19:27:08 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel+bounces-84474-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) client-ip=147.75.80.249; Authentication-Results: mx.google.com; dkim=pass header.i=@chromium.org header.s=google header.b=dmfOanEO; arc=pass (i=1 spf=pass spfdomain=chromium.org dkim=pass dkdomain=chromium.org dmarc=pass fromdomain=chromium.org); spf=pass (google.com: domain of linux-kernel+bounces-84474-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.80.249 as permitted sender) smtp.mailfrom="linux-kernel+bounces-84474-linux.lists.archive=gmail.com@vger.kernel.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=chromium.org Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by am.mirrors.kernel.org (Postfix) with ESMTPS id 114871F2C355 for ; Wed, 28 Feb 2024 03:26:49 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 8093120329; Wed, 28 Feb 2024 03:26:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="dmfOanEO" Received: from mail-pl1-f179.google.com (mail-pl1-f179.google.com [209.85.214.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 40BED20320 for ; Wed, 28 Feb 2024 03:26:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709090800; cv=none; b=mSkzLowxIIuEqNmLLGovmCnJXQ+7TjFHfWB5GJ8fynbpfyl2aIfs0x85bbIaxgktnURua/AUWOXPxv32OJuye4q4410jHfD7eMgon/igKyoO1gpRcq0WkGdV9rBk7g6AvKR2scwifA2rpwiFy5+Ri9m6vDtn9xzJ988sCt7arzk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709090800; c=relaxed/simple; bh=8OtT/g4e41nvDmoPuiBisjrJJG5cIKIV/+8CKhLGz2c=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lliHfkpWUfS3CbbcUfeE2xBBd4dHT/Tk4NZq2gr7nHtCgdVC8kV7UICSw6BCZ1U3J0KClmxTgzNrfg1NeWhgRAULeYmTwMzl1B8DH6YjZmR7tujrszeoLnh1ul6Mk0YhGDWy5RXsV83qXilTWuaraHDBuiXEjx+MF7e/+05Fv0k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org; spf=pass smtp.mailfrom=chromium.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b=dmfOanEO; arc=none smtp.client-ip=209.85.214.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=chromium.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=chromium.org Received: by mail-pl1-f179.google.com with SMTP id d9443c01a7336-1dc1ff3ba1aso42593365ad.3 for ; Tue, 27 Feb 2024 19:26:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1709090798; x=1709695598; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=xfBHH2R+HpI9h6VdbpXXPvs6htYiUptEJQWxbn/nS7o=; b=dmfOanEOPRmEkibxq0rqo1NX8rmPlAnLxy7s9j4oqUGhZIjXnZNsYRRkAu/BDegIin +ePTQL5t1sJrdVRo4SOgMkJMtVmtWXADPOU8VwnbOSVAEUOKb9YQMofo6q2qUusb1wIU Qkq2coYwczVO0NjaNT58WT7NSH/kd51DE6v+M= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709090798; x=1709695598; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=xfBHH2R+HpI9h6VdbpXXPvs6htYiUptEJQWxbn/nS7o=; b=d8I+fm9m5MPgX9X4xb/Wnb60qzTAWS1sKZFA0VKy9NbWPEP/8j2VL2TIfDyA9ArZ/c 0Dx7lREt6GMeju6RgMpz5ZR6E6+At/l5NvBy438PuWmSThE8Psx9Px/gMfGy21y39d4d WsCVBvqi3CN8kCKnRdcHPhDio8fD8xcivOZ5GjRzCrvf5QKmo03ibAAmv8C5KJ35DYAB zkPM2X3a/AYLhf7ZlHmAPgDoFq6MumXi1kB0Xvej3CZq3jOyD7FVhA8uzJUAelk/MVjY RcU3CgqZhD7YlKAfa7D/LLVzoOmh/wXFMiUhVFLKXp1lu8XiHupycwDKpnNEcBNOM6pU ew/Q== X-Forwarded-Encrypted: i=1; AJvYcCUBC6E1D9dbSo/F23ah0EafUS6aMZVEStXCuqfw3xmosTfLESLLZzDAJMu6dzax3BbUjhhmxVBjdIYh1xBIW5khtnw7keSmci2qZJ/C X-Gm-Message-State: AOJu0YyjhwpQWkXPDXmviBh995+i7sQl8aWkyC4dMUUnd1QcwrPpIOSH gNd509UHddJBpRp9xSPXmU5Q/mM0ju1dke8OW58p8T0xG65ZgSDIHiNMCP7hmg== X-Received: by 2002:a17:903:2309:b0:1dc:b4ef:b199 with SMTP id d9-20020a170903230900b001dcb4efb199mr5260618plh.36.1709090798499; Tue, 27 Feb 2024 19:26:38 -0800 (PST) Received: from google.com ([2401:fa00:8f:203:f4f0:fb4d:aa01:9068]) by smtp.gmail.com with ESMTPSA id 5-20020a170902c24500b001d7252fef6bsm2217289plg.299.2024.02.27.19.26.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Feb 2024 19:26:38 -0800 (PST) Date: Wed, 28 Feb 2024 12:26:33 +0900 From: Sergey Senozhatsky To: Chengming Zhou Cc: minchan@kernel.org, senozhatsky@chromium.org, akpm@linux-foundation.org, hannes@cmpxchg.org, nphamcs@gmail.com, yosryahmed@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm/zsmalloc: don't need to reserve LSB in handle Message-ID: <20240228032633.GD11972@google.com> References: <20240228023854.3511239-1-chengming.zhou@linux.dev> Precedence: bulk X-Mailing-List: linux-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: <20240228023854.3511239-1-chengming.zhou@linux.dev> On (24/02/28 02:38), Chengming Zhou wrote: > We will save allocated tag in the object header to indicate that it's > allocated. > > handle |= OBJ_ALLOCATED_TAG; > > So the object header needs to reserve LSB for this tag bit. > > But the handle itself doesn't need to reserve LSB to save tag, since > it's only used to find the position of object, by (pfn + obj_idx). > So remove LSB reserve from handle, one more bit can be used as obj_idx. > > Signed-off-by: Chengming Zhou Reviewed-by: Sergey Senozhatsky