From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: + =?US-ASCII?Q?mm-memcontrol-make-swap-tracking-an-integral-part-of-memo?= =?US-ASCII?Q?ry-control-fix.patch?= added to -mm tree Date: Thu, 21 May 2020 12:55:08 -0700 Message-ID: <20200521195508.7i5_qF8UC%akpm@linux-foundation.org> References: <20200513175005.1f4839360c18c0238df292d1@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Return-path: Received: from mail.kernel.org ([198.145.29.99]:42648 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728635AbgEUTzL (ORCPT ); Thu, 21 May 2020 15:55:11 -0400 In-Reply-To: <20200513175005.1f4839360c18c0238df292d1@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: alex.shi@linux.alibaba.com, bsingharora@gmail.com, guro@fb.com, hannes@cmpxchg.org, hughd@google.com, iamjoonsoo.kim@lge.com, kirill@shutemov.name, mhocko@kernel.org, mm-commits@vger.kernel.org, naresh.kamboju@linaro.org, shakeelb@google.com The patch titled Subject: mm-memcontrol-make-swap-tracking-an-integral-part-of-memory-control-fix has been added to the -mm tree. Its filename is mm-memcontrol-make-swap-tracking-an-integral-part-of-memory-control-fix.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-make-swap-tracking-an-integral-part-of-memory-control-fix.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-make-swap-tracking-an-integral-part-of-memory-control-fix.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Hugh Dickins Subject: mm-memcontrol-make-swap-tracking-an-integral-part-of-memory-control-fix Fix crash with cgroup_disable=memory: > > > > + mkfs -t ext4 /dev/disk/by-id/ata-TOSHIBA_MG04ACA100N_Y8NRK0BPF6XF > > > > mke2fs 1.43.8 (1-Jan-2018) > > > > Creating filesystem with 244190646 4k blocks and 61054976 inodes > > > > Filesystem UUID: 3bb1a285-2cb4-44b4-b6e8-62548f3ac620 > > > > Superblock backups stored on blocks: > > > > 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, > > > > 4096000, 7962624, 11239424, 20480000, 23887872, 71663616, 78675968, > > > > 102400000, 214990848 > > > > Allocating group tables: 0/7453 done > > > > Writing inode tables: 0/7453 done > > > > Creating journal (262144 blocks): [ 35.502102] BUG: kernel NULL > > > > pointer dereference, address: 000000c8 > > > > [ 35.508372] #PF: supervisor read access in kernel mode > > > > [ 35.513506] #PF: error_code(0x0000) - not-present page > > > > [ 35.518638] *pde = 00000000 > > > > [ 35.521514] Oops: 0000 [#1] SMP > > > > [ 35.524652] CPU: 0 PID: 145 Comm: kswapd0 Not tainted > > > > 5.7.0-rc6-next-20200519+ #1 > > > > [ 35.532121] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS > > > > 2.2 05/23/2018 > > > > [ 35.539507] EIP: mem_cgroup_get_nr_swap_pages+0x28/0x60 do_memsw_account() used to be automatically false when the cgroup controller was disabled. Now that it's replaced by cgroup_memory_noswap, for which this isn't true, make the mem_cgroup_disabled() checks explicit in the swap control API. [hannes@cmpxchg.org: use mem_cgroup_disabled() in all API functions] Link: http://lkml.kernel.org/r/20200521191746.GB815980@cmpxchg.org Signed-off-by: Johannes Weiner Reported-by: Naresh Kamboju Debugged-by: Hugh Dickins Debugged-by: Michal Hocko Cc: Joonsoo Kim Cc: Alex Shi Cc: "Kirill A. Shutemov" Cc: Roman Gushchin Cc: Shakeel Butt Cc: Balbir Singh Signed-off-by: Andrew Morton --- mm/memcontrol.c | 47 ++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 41 insertions(+), 6 deletions(-) --- a/mm/memcontrol.c~mm-memcontrol-make-swap-tracking-an-integral-part-of-memory-control-fix +++ a/mm/memcontrol.c @@ -6882,6 +6882,9 @@ void mem_cgroup_swapout(struct page *pag VM_BUG_ON_PAGE(PageLRU(page), page); VM_BUG_ON_PAGE(page_count(page), page); + if (mem_cgroup_disabled()) + return; + if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) return; @@ -6947,6 +6950,10 @@ int mem_cgroup_try_charge_swap(struct pa struct mem_cgroup *memcg; unsigned short oldid; + if (mem_cgroup_disabled()) + return 0; + + /* Only cgroup2 has swap.max */ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) return 0; @@ -6991,6 +6998,9 @@ void mem_cgroup_uncharge_swap(swp_entry_ struct mem_cgroup *memcg; unsigned short id; + if (mem_cgroup_disabled()) + return; + id = swap_cgroup_record(entry, 0, nr_pages); rcu_read_lock(); memcg = mem_cgroup_from_id(id); @@ -7011,12 +7021,25 @@ long mem_cgroup_get_nr_swap_pages(struct { long nr_swap_pages = get_nr_swap_pages(); - if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) - return nr_swap_pages; + if (mem_cgroup_disabled()) + goto out; + + /* Swap control disabled */ + if (cgroup_memory_noswap) + goto out; + + /* + * Only cgroup2 has swap.max, cgroup1 does mem+sw accounting, + * which does not place restrictions specifically on swap. + */ + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + goto out; + for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) nr_swap_pages = min_t(long, nr_swap_pages, READ_ONCE(memcg->swap.max) - page_counter_read(&memcg->swap)); +out: return nr_swap_pages; } @@ -7028,18 +7051,30 @@ bool mem_cgroup_swap_full(struct page *p if (vm_swap_full()) return true; - if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) - return false; + + if (mem_cgroup_disabled()) + goto out; + + /* Swap control disabled */ + if (cgroup_memory_noswap) + goto out; + + /* + * Only cgroup2 has swap.max, cgroup1 does mem+sw accounting, + * which does not place restrictions specifically on swap. + */ + if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) + goto out; memcg = page->mem_cgroup; if (!memcg) - return false; + goto out; for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) if (page_counter_read(&memcg->swap) * 2 >= READ_ONCE(memcg->swap.max)) return true;