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 86B0D6AB9 for ; Wed, 23 Mar 2022 23:06:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E818C36AE7; Wed, 23 Mar 2022 23:06:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648076778; bh=4hNNHxiVyfteaC8NEM+kjhvExFaE8Bhlb1AV9KeKdeY=; h=Date:To:From:In-Reply-To:Subject:From; b=bWw+flDnUcPt/agnl/uqsZAVR72bp2KE0fa8Rf7u0H9p446bqhRT+pTwVzn90AWbv QomyPHzvgwuiAC80R5lR+fGtitL7c1SwfWRjesqYXCZYd2X8r6Nty2ZBFgNQPMnpbS agoGS5KaIMKYPgnyvI3tJ/aV3JtL3JApfmE+1ZOo= Date: Wed, 23 Mar 2022 16:06:17 -0700 To: viro@zeniv.linux.org.uk,0x7f454c46@gmail.com,avagin@gmail.com,akpm@linux-foundation.org,patches@lists.linux.dev,linux-mm@kvack.org,mm-commits@vger.kernel.org,torvalds@linux-foundation.org,akpm@linux-foundation.org From: Andrew Morton In-Reply-To: <20220323160453.65922ced539cbf445b191555@linux-foundation.org> Subject: [patch 20/41] fs/pipe: use kvcalloc to allocate a pipe_buffer array Message-Id: <20220323230618.4E818C36AE7@smtp.kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: From: Andrei Vagin Subject: fs/pipe: use kvcalloc to allocate a pipe_buffer array Right now, kcalloc is used to allocate a pipe_buffer array. The size of the pipe_buffer struct is 40 bytes. kcalloc allows allocating reliably chunks with sizes less or equal to PAGE_ALLOC_COSTLY_ORDER (3). It means that the maximum pipe size is 3.2MB in this case. In CRIU, we use pipes to dump processes memory. CRIU freezes a target process, injects a parasite code into it and then this code splices memory into pipes. If a maximum pipe size is small, we need to do many iterations or create many pipes. kvcalloc attempt to allocate physically contiguous memory, but upon failure, fall back to non-contiguous (vmalloc) allocation and so it isn't limited by PAGE_ALLOC_COSTLY_ORDER. The maximum pipe size for non-root users is limited by the /proc/sys/fs/pipe-max-size sysctl that is 1MB by default, so only the root user will be able to trigger vmalloc allocations. Link: https://lkml.kernel.org/r/20220104171058.22580-1-avagin@gmail.com Signed-off-by: Andrei Vagin Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Alexander Viro Signed-off-by: Andrew Morton --- fs/pipe.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/fs/pipe.c~fs-pipe-use-kvcalloc-to-allocate-a-pipe_buffer-array +++ a/fs/pipe.c @@ -804,7 +804,7 @@ struct pipe_inode_info *alloc_pipe_info( if (too_many_pipe_buffers_hard(user_bufs) && pipe_is_unprivileged_user()) goto out_revert_acct; - pipe->bufs = kcalloc(pipe_bufs, sizeof(struct pipe_buffer), + pipe->bufs = kvcalloc(pipe_bufs, sizeof(struct pipe_buffer), GFP_KERNEL_ACCOUNT); if (pipe->bufs) { @@ -849,7 +849,7 @@ void free_pipe_info(struct pipe_inode_in #endif if (pipe->tmp_page) __free_page(pipe->tmp_page); - kfree(pipe->bufs); + kvfree(pipe->bufs); kfree(pipe); } @@ -1264,8 +1264,7 @@ int pipe_resize_ring(struct pipe_inode_i if (nr_slots < n) return -EBUSY; - bufs = kcalloc(nr_slots, sizeof(*bufs), - GFP_KERNEL_ACCOUNT | __GFP_NOWARN); + bufs = kvcalloc(nr_slots, sizeof(*bufs), GFP_KERNEL_ACCOUNT); if (unlikely(!bufs)) return -ENOMEM; @@ -1292,7 +1291,7 @@ int pipe_resize_ring(struct pipe_inode_i head = n; tail = 0; - kfree(pipe->bufs); + kvfree(pipe->bufs); pipe->bufs = bufs; pipe->ring_size = nr_slots; if (pipe->max_usage > nr_slots) _ 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 A00ADC433EF for ; Wed, 23 Mar 2022 23:06:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345416AbiCWXIL (ORCPT ); Wed, 23 Mar 2022 19:08:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53614 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345399AbiCWXHt (ORCPT ); Wed, 23 Mar 2022 19:07:49 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59BD590CD2 for ; Wed, 23 Mar 2022 16:06:19 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E968B617F1 for ; Wed, 23 Mar 2022 23:06:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E818C36AE7; Wed, 23 Mar 2022 23:06:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1648076778; bh=4hNNHxiVyfteaC8NEM+kjhvExFaE8Bhlb1AV9KeKdeY=; h=Date:To:From:In-Reply-To:Subject:From; b=bWw+flDnUcPt/agnl/uqsZAVR72bp2KE0fa8Rf7u0H9p446bqhRT+pTwVzn90AWbv QomyPHzvgwuiAC80R5lR+fGtitL7c1SwfWRjesqYXCZYd2X8r6Nty2ZBFgNQPMnpbS agoGS5KaIMKYPgnyvI3tJ/aV3JtL3JApfmE+1ZOo= Date: Wed, 23 Mar 2022 16:06:17 -0700 To: viro@zeniv.linux.org.uk, 0x7f454c46@gmail.com, avagin@gmail.com, akpm@linux-foundation.org, patches@lists.linux.dev, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org From: Andrew Morton In-Reply-To: <20220323160453.65922ced539cbf445b191555@linux-foundation.org> Subject: [patch 20/41] fs/pipe: use kvcalloc to allocate a pipe_buffer array Message-Id: <20220323230618.4E818C36AE7@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Andrei Vagin Subject: fs/pipe: use kvcalloc to allocate a pipe_buffer array Right now, kcalloc is used to allocate a pipe_buffer array. The size of the pipe_buffer struct is 40 bytes. kcalloc allows allocating reliably chunks with sizes less or equal to PAGE_ALLOC_COSTLY_ORDER (3). It means that the maximum pipe size is 3.2MB in this case. In CRIU, we use pipes to dump processes memory. CRIU freezes a target process, injects a parasite code into it and then this code splices memory into pipes. If a maximum pipe size is small, we need to do many iterations or create many pipes. kvcalloc attempt to allocate physically contiguous memory, but upon failure, fall back to non-contiguous (vmalloc) allocation and so it isn't limited by PAGE_ALLOC_COSTLY_ORDER. The maximum pipe size for non-root users is limited by the /proc/sys/fs/pipe-max-size sysctl that is 1MB by default, so only the root user will be able to trigger vmalloc allocations. Link: https://lkml.kernel.org/r/20220104171058.22580-1-avagin@gmail.com Signed-off-by: Andrei Vagin Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Alexander Viro Signed-off-by: Andrew Morton --- fs/pipe.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/fs/pipe.c~fs-pipe-use-kvcalloc-to-allocate-a-pipe_buffer-array +++ a/fs/pipe.c @@ -804,7 +804,7 @@ struct pipe_inode_info *alloc_pipe_info( if (too_many_pipe_buffers_hard(user_bufs) && pipe_is_unprivileged_user()) goto out_revert_acct; - pipe->bufs = kcalloc(pipe_bufs, sizeof(struct pipe_buffer), + pipe->bufs = kvcalloc(pipe_bufs, sizeof(struct pipe_buffer), GFP_KERNEL_ACCOUNT); if (pipe->bufs) { @@ -849,7 +849,7 @@ void free_pipe_info(struct pipe_inode_in #endif if (pipe->tmp_page) __free_page(pipe->tmp_page); - kfree(pipe->bufs); + kvfree(pipe->bufs); kfree(pipe); } @@ -1264,8 +1264,7 @@ int pipe_resize_ring(struct pipe_inode_i if (nr_slots < n) return -EBUSY; - bufs = kcalloc(nr_slots, sizeof(*bufs), - GFP_KERNEL_ACCOUNT | __GFP_NOWARN); + bufs = kvcalloc(nr_slots, sizeof(*bufs), GFP_KERNEL_ACCOUNT); if (unlikely(!bufs)) return -ENOMEM; @@ -1292,7 +1291,7 @@ int pipe_resize_ring(struct pipe_inode_i head = n; tail = 0; - kfree(pipe->bufs); + kvfree(pipe->bufs); pipe->bufs = bufs; pipe->ring_size = nr_slots; if (pipe->max_usage > nr_slots) _