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| author | Gerald Schaefer <gerald.schaefer@linux.ibm.com> | 2024-09-02 15:02:19 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-10-17 16:08:30 +0300 |
| commit | dced2c9d661e3eee3d80550730d9f3c5c3e04d1a (patch) | |
| tree | 422d79ccf77e0fdb1de78d479af4f3962a116064 /arch/s390 | |
| parent | 1cd197813eb85905b54a7efd34abb9d110fffe2a (diff) | |
| download | linux-dced2c9d661e3eee3d80550730d9f3c5c3e04d1a.tar.xz | |
s390/mm: Add cond_resched() to cmm_alloc/free_pages()
[ Upstream commit 131b8db78558120f58c5dc745ea9655f6b854162 ]
Adding/removing large amount of pages at once to/from the CMM balloon
can result in rcu_sched stalls or workqueue lockups, because of busy
looping w/o cond_resched().
Prevent this by adding a cond_resched(). cmm_free_pages() holds a
spin_lock while looping, so it cannot be added directly to the existing
loop. Instead, introduce a wrapper function that operates on maximum 256
pages at once, and add it there.
Signed-off-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/mm/cmm.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/arch/s390/mm/cmm.c b/arch/s390/mm/cmm.c index 1141c8d5c0d0..9b4304fa37bf 100644 --- a/arch/s390/mm/cmm.c +++ b/arch/s390/mm/cmm.c @@ -95,11 +95,12 @@ static long cmm_alloc_pages(long nr, long *counter, (*counter)++; spin_unlock(&cmm_lock); nr--; + cond_resched(); } return nr; } -static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list) +static long __cmm_free_pages(long nr, long *counter, struct cmm_page_array **list) { struct cmm_page_array *pa; unsigned long addr; @@ -123,6 +124,21 @@ static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list) return nr; } +static long cmm_free_pages(long nr, long *counter, struct cmm_page_array **list) +{ + long inc = 0; + + while (nr) { + inc = min(256L, nr); + nr -= inc; + inc = __cmm_free_pages(inc, counter, list); + if (inc) + break; + cond_resched(); + } + return nr + inc; +} + static int cmm_oom_notify(struct notifier_block *self, unsigned long dummy, void *parm) { |