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 7E57E8489 for ; Fri, 16 Aug 2024 05:02:25 +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=1723784546; cv=none; b=Mt+/f8wexyk8wKQK+iHPi5gp/1CXNeppGui7me2VTSL+y1K5vnsUIjGEGSvY9J5XHt125nKdU81aNn1krI9KA2UwcVkY+G3WK5yBGL0AzDyIOedPaG5Vogr4BgJ7VCirfN2zmCpXwaK5bk57hDV4YUbtbqr8x9r4phE1PQ8dKTE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723784546; c=relaxed/simple; bh=AEkbPxdpS1Ba7oCEoeKShqIutg2Z5i+vZsjUzLWOK8I=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=P843UgDYRHGsBNl+/dnc4UEqtVTECCwXQVG83MQj9iBG9rXoJLNoEF9Y0oXEuNOwyhSvy2n/z4hTZ8/L3oDAxWgQYuN5lNSsO07M2SC5e33SvGrgEoB8XLglpbUbTGko2EHCmr9nJCa1N+1x27cxSQ4D2x4epugbsWJ24BpwK+I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=zH6d/rhu; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="zH6d/rhu" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B7F31C32782; Fri, 16 Aug 2024 05:02:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1723784544; bh=AEkbPxdpS1Ba7oCEoeKShqIutg2Z5i+vZsjUzLWOK8I=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=zH6d/rhuRdJ6fGA+XdSY3a7F+ley1JXLdbDje+0mEyphAhSz0ZKAPYA+T4NM7fjA2 TFwc4OPNfVoyuM02a5WCuufM0ToxXVrvF9DXEmEYT/GpUkRYQDlguxR5b1JTHEuHn6 tRzJnJwzwF6advmIHtfGGnsQy4SEdBxxHxYMWisg= Date: Thu, 15 Aug 2024 22:02:24 -0700 From: Andrew Morton To: Gao Xiang Cc: "Huang, Ying" , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/migrate: fix deadlock in migrate_pages_batch() on large folios Message-Id: <20240815220224.d7970835d5c12b4833bd04dc@linux-foundation.org> In-Reply-To: References: <20240728154913.4023977-1-hsiangkao@linux.alibaba.com> <87plqx0yh2.fsf@yhuang6-desk2.ccr.corp.intel.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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-Transfer-Encoding: 7bit On Mon, 29 Jul 2024 09:58:02 +0800 Gao Xiang wrote: > > For the fix, I think that we should still respect migrate_mode because > > users may prefer migration success over blocking. > > > > @@ -1492,11 +1492,17 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio, > > return rc; > > } > > > > -static inline int try_split_folio(struct folio *folio, struct list_head *split_folios) > > +static inline int try_split_folio(struct folio *folio, struct list_head *split_folios, > > + enum migrate_mode mode) > > { > > int rc; > > > > - folio_lock(folio); > > + if (mode == MIGRATE_ASYNC) { > > + if (!folio_trylock(folio)) > > + return -EAGAIN; > > + } else { > > + folio_lock(folio); > > + } > > rc = split_folio_to_list(folio, split_folios); > > folio_unlock(folio); > > if (!rc) > > Okay, yeah it looks better since it seems I missed the fallback > part in migrate_pages_sync(). > > Let me send the next version to follow your advice, thanks. The author seems to have disappeared. Should we merge this as-is or does someone want to take a look at developing a v2? Thanks.