From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from cloud.peff.net (cloud.peff.net [217.216.95.84]) (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 A917C38AC79 for ; Thu, 9 Apr 2026 22:21:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.216.95.84 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775773300; cv=none; b=WcndNzog75P4R2gnosNJiNZAub6P/qVUv/NNw3cD+z6XbfvOfd8I2e72Of1GjxZVj0Y+WXrzOKqGJp4QwZg+YH7hT403E82xjKP/8/8ahw3EPlfgQwX7MwmqrRWfrju1mM5HcEgijh7B8Ltq+fome5TS3WdbkW0CHhbMe+wmn2o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775773300; c=relaxed/simple; bh=5gLqtzIrx3/Uir1PZJmLD7ERREGA2riMagE/OF8YdgQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ovCYtdmXW+04niQkHW4gJy3xcvHIDMILKOFfcTX7fCoD/wj4GPExlbbjAe5ErHdFDxlYZLy5skFTsAKciVuWlu9/DVTJkpmbiPRM2ph4WhdHNEwnHx1rxPpGOvzQQKMEyapHnn6jLnN+SNmGOdnwxrU9ZevvhoUMsqD3MznHLMc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=peff.net; spf=pass smtp.mailfrom=peff.net; dkim=pass (2048-bit key) header.d=peff.net header.i=@peff.net header.b=OksBWkX3; arc=none smtp.client-ip=217.216.95.84 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=peff.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=peff.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=peff.net header.i=@peff.net header.b="OksBWkX3" Received: (qmail 295486 invoked by uid 106); 9 Apr 2026 22:21:32 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=peff.net; h=date:from:to:cc:subject:message-id:references:mime-version:content-type:in-reply-to; s=20240930; bh=5gLqtzIrx3/Uir1PZJmLD7ERREGA2riMagE/OF8YdgQ=; b=OksBWkX3H0hw23PDSTG0uhzdDWkzXUwwDIf0ahJZMkjNPLuJFY/uaFS6ulW3wPHTYy2QjuRs4s1rtqwBY8849x+LmUJAKUADH2EcA3J51/4iT0SuW84hkg5y71QiGjBd7i/lX+mxL+F+7fpx9feRURiCgzv/SPgat8mg7mJ4Vjtv9wsQKx6QKjkz5kCXrTLxg+zz1hIfFk329ASTyOxkpRPwksM5ut7ZzjuRfN1CT5bAD2fSZ8Ox/V1OdWWnnvHLvWu3GCHJr7VaRqV4TgQYmSOS2m42xSpAMiL+f0alQo9R9WDkyCQLLLlVukgEKsgyPEYmXahHm57WuQigNIweWA== Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with ESMTP; Thu, 09 Apr 2026 22:21:32 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 489207 invoked by uid 111); 9 Apr 2026 22:21:31 -0000 Received: from coredump.intra.peff.net (HELO coredump.intra.peff.net) (10.0.0.2) by peff.net (qpsmtpd/0.94) with (TLS_AES_256_GCM_SHA384 encrypted) ESMTPS; Thu, 09 Apr 2026 18:21:31 -0400 Authentication-Results: peff.net; auth=none Date: Thu, 9 Apr 2026 18:21:31 -0400 From: Jeff King To: Junio C Hamano Cc: rsbecker@nexbridge.com, Patrick Steinhardt , git@vger.kernel.org Subject: Re: Re* 2.54.0-rc1 NO_WRITEV=Nope does not work Message-ID: <20260409222131.GA3130242@coredump.intra.peff.net> References: <028901dcc859$d2419470$76c4bd50$@nexbridge.com> <20260409211049.GA3119065@coredump.intra.peff.net> Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Thu, Apr 09, 2026 at 02:53:28PM -0700, Junio C Hamano wrote: > > Yuck. I think for 2.54 we either have to truly implement MAX_IO_SIZE > > support, or we have to revert the use of writev() in send_sideband() > > until we do. > > Sigh again. Yeah, I feel the same way. :( I would be happy if somebody could prove me wrong, though. > $ git log -Swritev --oneline 8023abc632^.. > 89152af176 cmake: use writev(3p) wrapper as needed > 26986f4cba sideband: use writev(3p) to send pktlines > 1970fcef93 wrapper: introduce writev(3p) wrappers > 3b9b2c2a29 compat/posix: introduce writev(3p) wrapper > > Reverting them gave us the following patch relative to the tip of > 'master'. If we are planning to improve the topic post-release (and I think that is a good idea), then we can do a much smaller revert. If we just revert 26986f4cba (sideband: use writev(3p) to send pktlines, 2026-03-13), then nobody calls writev (neither the real one nor our fallback). The wrappers are dead code until we bring it back, but it may make things easier for fixing post-2.54. -Peff