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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 80222C982D7 for ; Fri, 18 Sep 2026 20:43:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8C3A66B0098; Fri, 18 Sep 2026 16:43:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 874446B0099; Fri, 18 Sep 2026 16:43:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7B1F86B009B; Fri, 18 Sep 2026 16:43:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 59D5E6B0098 for ; Fri, 18 Sep 2026 16:43:46 -0400 (EDT) Received: from smtpin19.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id A0CF2807D9 for ; Fri, 18 Sep 2026 20:43:45 +0000 (UTC) X-FDA: 85228059210.19.982A723 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf30.hostedemail.com (Postfix) with ESMTP id D4C1B80008 for ; Fri, 18 Sep 2026 20:43:43 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=sRguR3+D; spf=pass (imf30.hostedemail.com: domain of akpm@linux-foundation.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1789764224; 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=s5ambLtJv/AuCg2Coh5juy9jqmqcd8mcPlwipY+ptBk=; b=hn62xqDK+Vc10AVlIoLkPzeQGjttfmIj+FkKt9TJJXe+hPe2Jsb0UaZYjINf81A8MtVEgm 46wGDKMcETcILMuMth3INUTdOhKMqJihjKJkQCmHeAOpQRgXGdZ5yjGRKIzjU2sFebWmkz hCcbTXi3bbZdQ2aAQiSHHxb7KIzJxa0= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=sRguR3+D; spf=pass (imf30.hostedemail.com: domain of akpm@linux-foundation.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789764224; b=7Or8DSmL+Kv/fweugSAu3oR3swLqzLa3/ZddqP/dVDYPf/2g0J6VKLo25gX3e7mQMVBmfP AzxUQn150iZawVIdOPQiQX4QFfAgm7GVSwtz5jYpq+OrgzygXN3yG7RQsEKUveqxmh+Amh /Wc2sVhiqYTUxO27Yo4LpL2Luqt4/+w= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 572826053D; Fri, 18 Sep 2026 20:43:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3BF11F000FF; Fri, 18 Sep 2026 20:43:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789764223; bh=s5ambLtJv/AuCg2Coh5juy9jqmqcd8mcPlwipY+ptBk=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=sRguR3+DzyOGGRDDZzh1ApJrkGYDqyORnnvJ88iY2Aw8UWAGYl3NM+ahgzTDYCNI1 43gfg1whBdkDPOtx1iSARXCM0t1z/GQ1LGXdyUdJ149p0YR5KdlJxPDwIk/RlwNx1t uzb4TdoOIM3UqeyRUCvsdl8NzSYJmN8raMNiQCWs= Date: Fri, 18 Sep 2026 13:43:42 -0700 From: Andrew Morton To: paulmck@kernel.org Cc: Breno Leitao , Hugh Dickins , Baolin Wang , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, stable@vger.kernel.org Subject: Re: [PATCH] mm/shmem: report RCU-tasks quiescent states while undoing a range Message-Id: <20260918134342.c50423cfe3b2910e899226f2@linux-foundation.org> In-Reply-To: References: <20260918-shmem-tasks-rcu-v1-1-79acf91a2569@debian.org> <20260918123239.8f25b984ca280fcc11ef6e6a@linux-foundation.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Stat-Signature: 5x536tfbzgwf7b1dynw3gzc4puasxo7f X-Rspamd-Queue-Id: D4C1B80008 X-Rspamd-Server: rspam07 X-HE-Tag: 1789764223-342907 X-HE-Meta: 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 ihT6keLY BmesjkG8NqJ9PRRmtlBi7g8TEIEzXyl6dSAn7fAdzBqduTyCosM0OkQ/UcDS6MdgjMiMtDJ6qbRoHH0t0vRx+hmZBTZVCvurDT8R/1vRRg+TyGdWcItkpy3ue27K8H2qUwznwPAQ9M5Nlx2uXaKu7Mzs0/4E3S8GKBzrShvpbIKPGcXxzPqBc7cnLE6KXSOMFTbzLk6h5BXxmGDgQALx+uBVAgIvctn7cw43L15kSdFbfdqmbqFa0zue3rDYc1CM4aKb5WSQRgBt6j1g= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 18 Sep 2026 13:24:53 -0700 "Paul E. McKenney" wrote: > > > > > --- a/mm/shmem.c > > > +++ b/mm/shmem.c > > > @@ -1367,7 +1367,7 @@ static void shmem_undo_range(struct inode *inode, loff_t lstart, uoff_t lend, > > > } > > > folio_batch_remove_exceptionals(&fbatch); > > > folio_batch_release(&fbatch); > > > - cond_resched(); > > > + cond_resched_tasks_rcu_qs(); > > > > Won't this change remove the cond_resched() function from old kernels > > which really want it? > > The cond_resched_tasks_rcu_qs() macro implies cond_resched(): > > #define cond_resched_tasks_rcu_qs() \ > do { \ > rcu_tasks_qs(current, false); \ > cond_resched(); \ > } while (0) > Oh, should've looked. And it appears to have been this way forever, so s/cond_resched/cond_resched_tasks_rcu_qs/ won't break old kernels.