From nobody Fri Dec 19 07:48:39 2025 Received: from dggsgout11.his.huawei.com (dggsgout11.his.huawei.com [45.249.212.51]) (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 C810B20C016; Thu, 5 Jun 2025 13:17:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.51 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749129423; cv=none; b=WtIMQG9VKOVEiUfTf5hsFji0EYwM1O3ju/+nlTqIu8hbuFm5Y1DMmW/azglH7lOTgjAgL0zgN72c9tt16xpf8GFH9EUCooKo5SMXeh+gAD8uuLbQuMxGScSki5g5aq2Wv6EpHjtANuJB9Cl2uE7nDdnfeEshR5/umRDwZ5/wMS4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749129423; c=relaxed/simple; bh=k2P5OpcOAeXgHAFYS+maLDSEn8kZiMRnQx6FsDhYg4k=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=nA1CaMkk6kNw7OVqz1pL621R3lAo9s+btkAoFqIctbR3jUmOc1ukdi2NizgX1HNxXA9zn4Q27zaL+1DciLGyigldHcbc0kyOUje0PhR0hAhaZr16tgnXiG8vlK0zgqD3qpXtg/K4POR4Hb6QMjMHR8kbo1yYRuOIiWY+y9qp5NA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com; spf=pass smtp.mailfrom=huaweicloud.com; arc=none smtp.client-ip=45.249.212.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=huaweicloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huaweicloud.com Received: from mail.maildlp.com (unknown [172.19.163.235]) by dggsgout11.his.huawei.com (SkyGuard) with ESMTPS id 4bClNC58GKzYQtws; Thu, 5 Jun 2025 21:16:59 +0800 (CST) Received: from mail02.huawei.com (unknown [10.116.40.112]) by mail.maildlp.com (Postfix) with ESMTP id BD0811A11C4; Thu, 5 Jun 2025 21:16:58 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.101.6]) by APP1 (Coremail) with SMTP id cCh0CgDnTH3HmEFobD9lOQ--.29489S6; Thu, 05 Jun 2025 21:16:58 +0800 (CST) From: Kemeng Shi To: hughd@google.com, baolin.wang@linux.alibaba.com, willy@infradead.org, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 4/7] mm: shmem: handle special case of shmem_recalc_inode() in it's caller Date: Fri, 6 Jun 2025 06:10:34 +0800 Message-Id: <20250605221037.7872-5-shikemeng@huaweicloud.com> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20250605221037.7872-1-shikemeng@huaweicloud.com> References: <20250605221037.7872-1-shikemeng@huaweicloud.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: cCh0CgDnTH3HmEFobD9lOQ--.29489S6 X-Coremail-Antispam: 1UD129KBjvJXoW7Aw48CFyDtrW3Zw4DKr1rJFb_yoW8Zw1xpr ZrK3yDJrWrAFyI9r9aya1kZrWag3y8GrWUt343u3s5u3WDJr17Kr4IyFy8Za4UCr9rJ3yS vr4xCr18ZF4Dt3DanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUPab4IE77IF4wAFF20E14v26rWj6s0DM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6rWj6s0DM7CIcVAFz4kK6r1j6r18M280x2IEY4vEnII2IxkI6r1a6r45M2 8IrcIa0xkI8VA2jI8067AKxVWUAVCq3wA2048vs2IY020Ec7CjxVAFwI0_Xr0E3s1l8cAv FVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2IY67AKxVW7JVWDJw A2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2z280aVAFwI0_GcCE 3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcVAq07x20xvEncxIr2 1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j6r18McIj6I8E87Iv 67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64vIr41lc7CjxVAaw2 AFwI0_JF0_Jw1l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAq x4xG67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r 1DMIIYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF 7I0E14v26r4j6F4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxV WUJVW8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxU s3kuDUUUU X-CM-SenderInfo: 5vklyvpphqwq5kxd4v5lfo033gof0z/ Content-Type: text/plain; charset="utf-8" The sepcial case in shmem_recalc_inode() is tailored for shmem_writepage(). By raising swapped before nrpages is lowered directly within shmem_writepage(), we can simplify code of shmem_recalc_inode() and eliminate the need of executing the special case code for all callers of shmem_recalc_inode(). Signed-off-by: Kemeng Shi --- mm/shmem.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/mm/shmem.c b/mm/shmem.c index 2349673b239b..9f5e1eccaacb 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -443,15 +443,6 @@ static void shmem_recalc_inode(struct inode *inode, lo= ng alloced, long swapped) info->swapped +=3D swapped; freed =3D info->alloced - info->swapped - READ_ONCE(inode->i_mapping->nrpages); - /* - * Special case: whereas normally shmem_recalc_inode() is called - * after i_mapping->nrpages has already been adjusted (up or down), - * shmem_writepage() has to raise swapped before nrpages is lowered - - * to stop a racing shmem_recalc_inode() from thinking that a page has - * been freed. Compensate here, to avoid the need for a followup call. - */ - if (swapped > 0) - freed +=3D swapped; if (freed > 0) info->alloced -=3D freed; spin_unlock(&info->lock); @@ -1694,9 +1685,16 @@ static int shmem_writepage(struct page *page, struct= writeback_control *wbc) list_add(&info->swaplist, &shmem_swaplist); =20 if (!folio_alloc_swap(folio, __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN= )) { - shmem_recalc_inode(inode, 0, nr_pages); + /* + * Raise swapped before nrpages is lowered to stop racing + * shmem_recalc_inode() from thinking that a page has been freed. + */ + spin_lock(&info->lock); + info->swapped +=3D nr_pages; + spin_unlock(&info->lock); swap_shmem_alloc(folio->swap, nr_pages); shmem_delete_from_page_cache(folio, swp_to_radix_entry(folio->swap)); + shmem_recalc_inode(inode, 0, 0); =20 mutex_unlock(&shmem_swaplist_mutex); BUG_ON(folio_mapped(folio)); --=20 2.30.0