From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25F52C54731 for ; Tue, 27 Aug 2024 15:34:38 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id ABFD96B007B; Tue, 27 Aug 2024 11:34:37 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A70016B0088; Tue, 27 Aug 2024 11:34:37 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 937086B0092; Tue, 27 Aug 2024 11:34:37 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 7334F6B007B for ; Tue, 27 Aug 2024 11:34:37 -0400 (EDT) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 21351141B00 for ; Tue, 27 Aug 2024 15:34:37 +0000 (UTC) X-FDA: 82498422594.13.C960BF2 Received: from mail-ed1-f48.google.com (mail-ed1-f48.google.com [209.85.208.48]) by imf29.hostedemail.com (Postfix) with ESMTP id 44B6D120013 for ; Tue, 27 Aug 2024 15:34:35 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=s5glfgED; spf=pass (imf29.hostedemail.com: domain of jannh@google.com designates 209.85.208.48 as permitted sender) smtp.mailfrom=jannh@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1724772788; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=U0HKBrlei1RgeNErLaGZftLQmyuipt/6wDs7cJ+sU9k=; b=6qXHa3Mm97lJpysikO7P8O9I/aEw7qX3rpxfJY1Ee9QYqNUtt8PZU84ttwVzGOueJbwVba ADU5d+BEUzFj4JZ9egBN3w+72WOK7UhI9gQGatpiDsbrhfS5wk66v3eotGV15rTDxCt9JY H8TaaSXK7fUY1LH3H/UlRTBDTjwTdTw= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1724772788; a=rsa-sha256; cv=none; b=Us1Xed244lAa3koi3y78Q8XAYvgSzp+9gMKUg/1Cs48M8LkToidwkeWAG87WXKRhiAp3xG lX/z5M0ozL1Jx+1qF+/4iN1is3hjngPfb5RCDKMk9YSNNnK0pOTvtSfCkd/TxpdaPi1egQ Qwk70XbkHQ0gMWm+rqzfu93H08jh6R4= ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=s5glfgED; spf=pass (imf29.hostedemail.com: domain of jannh@google.com designates 209.85.208.48 as permitted sender) smtp.mailfrom=jannh@google.com; dmarc=pass (policy=reject) header.from=google.com Received: by mail-ed1-f48.google.com with SMTP id 4fb4d7f45d1cf-5bebc830406so17869a12.0 for ; Tue, 27 Aug 2024 08:34:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1724772874; x=1725377674; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=U0HKBrlei1RgeNErLaGZftLQmyuipt/6wDs7cJ+sU9k=; b=s5glfgEDRL+Gx0K0DsbJQXECVR8Ye7BK0oHQI0T/NS8mGWISO1j742v1fs0P+UjR8F SzKvncVJlyDEoCmmahc/5VcfdSPFE7trIO9osFBHGkIr9kG3bc3KgorHPUmeFEFaPvJk +UBV5bxTuzrfbbt5w4JY2ZSyBRaYWxeyjWnzRtpc1ZYp2lAlTeEj/zCoV09uXjbu57sb Muwtyum8X2M4dHhTWttGzLtYJ+XMSMakimTXaKn0IXVqcmgmcI+hIfuY57VeUDSyrp5e AIWhkBGwvMS3bCtnzhbD9WzbcjoDA8srdjkoeVBpzYOO1FSWcoBmqM5CCKCwlaY1+5CV Dx6w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724772874; x=1725377674; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=U0HKBrlei1RgeNErLaGZftLQmyuipt/6wDs7cJ+sU9k=; b=PQbi1mqXRY502MEiVRt2/f7SzXnlhqhYcNBBe9DSz0EjfQCTOlwrZ3+vcA0zwNu6SW FWk7QuQYiny8TyJ98AL+r5Z40+iVvTNuSHFxFvVCFSs+66uornAm0joY1s1+EHC0p39t ndwgCEfKOZ9eaCsKIOEOb/wFHvahYBm7k8JnSHiw0guqyiHxs0tSmo7hhoWdkJypTLEx 3xGQzAGk0p5kAZYXCPQ/jZ0FqNr9CwVyqE70E/YHf93UlNJwP9Rz8Q6lF8bHOquucG6N APwG3oSHMDqB9Gnqmp+A5VfYUbsQN+K6ORpP6Xu3eeN89Q2zqDkKqP+EgQufPS011f87 ue5g== X-Forwarded-Encrypted: i=1; AJvYcCU26XJtxYuLbpR6aqZzNEzmb8XqNJ88wDCDq2o6F+MTayYxSQ9LfM/euHyuYZWcqcLyPHudKgln0Q==@kvack.org X-Gm-Message-State: AOJu0Yx26H4KuyRrSAQtXd36GJ3E+aV9/YV+C9MXHbfxdV2IdLe/Zb+c 7mRbMHEMttAAPKf+vSqk7QT7Ubd1eQZNrrcBCoPURYXE+LrZFqgaFNc/Me6Wt8gtOP324nGZNiU xdN5neeAJ0FSLgPtdkkNJ882Cmv7H62KKIqg0 X-Google-Smtp-Source: AGHT+IGVxQ9pelfyAqxYSuBA15Bsqtp8vc4S7Hl9aGA8KMF0HeckcFe+jQJPNdAt0o2TNQ70FcPkEJeKbEM0THD9RsQ= X-Received: by 2002:a05:6402:2709:b0:5c0:c108:fa96 with SMTP id 4fb4d7f45d1cf-5c0c108fdfcmr169378a12.1.1724772872916; Tue, 27 Aug 2024 08:34:32 -0700 (PDT) MIME-Version: 1.0 References: <20240826-zweihundert-luftkammer-9b2b47f4338e@brauner> <20240826-okkupieren-nachdenken-d88ac627e9bc@brauner> <6063be1b-7d4f-487e-9890-7e8f727d6324@suse.cz> In-Reply-To: <6063be1b-7d4f-487e-9890-7e8f727d6324@suse.cz> From: Jann Horn Date: Tue, 27 Aug 2024 17:33:54 +0200 Message-ID: Subject: Re: [PATCH] [RFC] mm: add kmem_cache_create_rcu() To: Vlastimil Babka Cc: Christian Brauner , Jens Axboe , "Paul E. McKenney" , Roman Gushchin , Linus Torvalds , linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: yqthdrzsa6woc41a3h5wyghjpo715w1t X-Rspamd-Queue-Id: 44B6D120013 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1724772875-257687 X-HE-Meta: U2FsdGVkX190pISzZwJbUVZDgT56pdcg5Q9T0NyLaAz9R2pBKh0y648nhVEb4RNJxp9gaLtMfgnSeB6z8f/qzedKVZ2zZRs0Wnc9caenZeRy5OPmCtfVfnVMzNN8nlXn+0vStAkMovUb+hZnQDzhYjzPPgIDMrd6JipfhnNfUcXFg/KVl7K613N+Lq/xKMlsRuG43rDUj/wxygO/leJ9xxkx8g/6nhehaL1gJFrI5ezAVnvFUt+4m8s/AWPGb6JSpG9jRYyYq0tY3w2QidV5Qp6aLVSytdiyCCU0TBO9gzG3yGs7A7fzfO+Ik1jluNlTxe4fu7tybxU1EZ+RIma8Qg3ah2rtnu98+ajfrh4AJp8ao/JfL9VDwWJzMeV2hF5SC6YfUPebCLtYGCpgnk2TckyaM30TfRRdJ4ZbBUjEtkf3xP5OIZTFuGS80LqbisCHYNMvk0yPaZJOi4HtL02+b2mtklTLyF7SNUhP7rLbTRwt1jBosKbWP6nGbf8HM3I1MMzOIoRo+rm1X58cJUp1nLWngeIPgztQi1sxPRGPJjndibhDrXqChSenvrogJNHcS2Ew4PLMlbaAR+3UviUhbBZtRMxRcq5hbUYuQdE4CZqqrHXowPFZaSK9dHrSW1aUogtpeYc9IxS12T/sCEhCcTGGesklI87LCNOqi2GcgHYr0Py8qo4d9abhvEsHelxGz6971nbcN+XIqdTU1w3TUWAuPPoSXcSYlrnajq7aCMiswwTAx+uYMUAEc0RdIJQ4Ba3Xx9JmAQ8G/pqclfrF5myK/VPJuT6Zox7kMAOABcgnb8w+ICyOnvfFeFi42FOfqWVvKj+5LNGqdzmPbeK4cDJNylTbI3sRXbwW1jgUhYGAlag2jX4RRfoHyN/wxKHCA5Bv9V9/gdyeO9h6cV+Bk25atQ+iPIZpzKJrjZla+v4cNBra622UCs0wHrdqk78Nbc5RVnotCCUIvCci84n Y7x7bc98 Fv8EE+OL3fRVgH9D29SCm5diP+GJGlpLh89cuGSXJQGaZqgId46lBqwBMMidJ5DfO5+MZvGDJmNiSe4qQZfp5b5LaR1p0X76U2f2+smQKhHkSG5RoyxOVQd//LAqqbQyApCCUDlTKd/2XqhsxiGGCbZs+Fl52GXmIAuzMoLS2Q7OOMxlPCYThRSXgHy73sk2MMhEMCFEWIzj8YeIltzDcOUg3xw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000341, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 27, 2024 at 4:05=E2=80=AFPM Vlastimil Babka wr= ote: > On 8/26/24 18:04, Christian Brauner wrote: > > diff --git a/include/linux/slab.h b/include/linux/slab.h > > index eb2bf4629157..fc3c3cc9f689 100644 > > --- a/include/linux/slab.h > > +++ b/include/linux/slab.h > > @@ -242,6 +242,10 @@ struct kmem_cache *kmem_cache_create_usercopy(cons= t char *name, > > slab_flags_t flags, > > unsigned int useroffset, unsigned int usersize, > > void (*ctor)(void *)); > > +struct kmem_cache *kmem_cache_create_rcu(const char *name, unsigned in= t size, > > + unsigned int offset, > > + slab_flags_t flags, > > + void (*ctor)(void *)); > > I wonder if there's a way to do this in a more generic way, we'd now have= 3 > variants and neither supports everything (what about both rcu offset and > usercopy?). The "pass all arguments as a struct" pattern might not look too bad (or alternatively, "pass all optional arguments as a struct"), as long as it's fine for unused arguments to be zero-initialized? Like: struct kcr_options { const char *name; unsigned int size; ... }; struct kmem_cache *kmem_cache_create(struct kcr_options opt); void blah() { kmem_cache_create((struct kcr_options){ .name =3D "blah", .size =3D ..., ... }); } I think maybe we can do this now that the kernel is C11? But I guess if we want to allow leaving out the freeptr_offset parameter, we'd have to have a flag to say whether the freeptr_offset parameter value should be used... Maybe my proposal is too overly fancy...