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
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
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@xxxxxxxxxxx: use mem_cgroup_disabled() in all API functions]
Link: http://lkml.kernel.org/r/20200521191746.GB815980@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Debugged-by: Hugh Dickins <hughd@xxxxxxxxxx>
Debugged-by: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Balbir Singh <bsingharora@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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;
-
+out:
return false;
}
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
mm-memcontrol-make-swap-tracking-an-integral-part-of-memory-control-fix.patch
mm-vmstat-add-events-for-pmd-based-thp-migration-without-split-fix.patch
