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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B4EB8C433F5 for ; Tue, 31 May 2022 14:42:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344041AbiEaOmn (ORCPT ); Tue, 31 May 2022 10:42:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39960 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236138AbiEaOmm (ORCPT ); Tue, 31 May 2022 10:42:42 -0400 Received: from m12-12.163.com (m12-12.163.com [220.181.12.12]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id E2A683AA4F; Tue, 31 May 2022 07:42:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id; bh=aHImv8CecLYVsqxKLx 3rBrqZ/D2QPjA2ce0QtxRVS6U=; b=EIltXozl2No9vHKMLM/uX+FcLKlsvVmznW RpEoePT6laOVkJojJXlZqLXi3QS2HswLuHavgogewG6axocynVEjZNMBdXAPyGxg UKBG4NYGScz5X0X48vmWxZzztj3oAacQ/JwFUqvZF+3XEshfF+HP3Sp0Vbswv9zD mR7j5nNK8= Received: from localhost.localdomain (unknown [171.221.150.250]) by smtp8 (Coremail) with SMTP id DMCowAAnhxMcKZZiLhmEFQ--.38243S2; Tue, 31 May 2022 22:41:38 +0800 (CST) From: Chen Lin To: kuba@kernel.org Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, alexander.duyck@gmail.com, netdev@vger.kernel.org, Chen Lin Subject: Re:Re: [PATCH v2] mm: page_frag: Warn_on when frag_alloc size is bigger than PAGE_SIZE Date: Tue, 31 May 2022 22:41:12 +0800 Message-Id: <1654008072-3136-1-git-send-email-chen45464546@163.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <20220530122918.549ef054@kernel.org> References: <20220530122918.549ef054@kernel.org> X-CM-TRANSID: DMCowAAnhxMcKZZiLhmEFQ--.38243S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7KF18AF1xGF43Gr1kKw45KFg_yoW8Ww15pr WUCFy5ZF45X3Z8CrW8Jrs8Aa4Fy3s3JFWUJayfJas8Zw13JrW0gw1DtrnIvryIkwn2kayI vr4jgr45Ca1Yq37anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0pRt5rOUUUUU= X-Originating-IP: [171.221.150.250] X-CM-SenderInfo: hfkh0kqvuwkkiuw6il2tof0z/1tbiGgISnlaEB7ovCgAAse Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org At 2022-05-31 02:29:18, "Jakub Kicinski" wrote: >On Mon, 30 May 2022 12:27:05 -0700 Jakub Kicinski wrote: >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index e008a3df0485..360a545ee5e8 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -5537,6 +5537,7 @@ EXPORT_SYMBOL(free_pages); >> * sk_buff->head, or to be used in the "frags" portion of skb_shared_info. >> */ >> static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, >> + unsigned int fragsz, >> gfp_t gfp_mask) >> { >> struct page *page = NULL; >> @@ -5549,7 +5550,7 @@ static struct page *__page_frag_cache_refill(struct page_frag_cache *nc, >> PAGE_FRAG_CACHE_MAX_ORDER); >> nc->size = page ? PAGE_FRAG_CACHE_MAX_SIZE : PAGE_SIZE; >> #endif >> - if (unlikely(!page)) >> + if (unlikely(!page && fragsz <= PAGE_SIZE)) >> page = alloc_pages_node(NUMA_NO_NODE, gfp, 0); >> >> nc->va = page ? page_address(page) : NULL; >> @@ -5576,7 +5577,7 @@ void *page_frag_alloc_align(struct page_frag_cache *nc, >> >> if (unlikely(!nc->va)) { >> refill: >> - page = __page_frag_cache_refill(nc, gfp_mask); >> + page = __page_frag_cache_refill(nc, fragsz, gfp_mask); >> if (!page) >> return NULL; > >Oh, well, the reuse also needs an update. We can slap a similar >condition next to the pfmemalloc check. The sample code above cannot completely solve the current problem. For example, when fragsz is greater than PAGE_FRAG_CACHE_MAX_SIZE(32768), __page_frag_cache_refill will return a memory of only 32768 bytes, so should we continue to expand the PAGE_FRAG_CACHE_MAX_SIZE? Maybe more work needs to be done