Linux v5.4.109-rt56-rc1

From: Tom Zanussi <[email protected]>

Dear RT Folks,

This is the RT stable review cycle of patch 5.4.109-rt56-rc1.

Please scream at me if I messed something up. Please test the patches too.

The -rc release will be uploaded to kernel.org and will be deleted when the final release is out. This is just a review release (or release candidate).

The pre-releases will not be pushed to the git repository, only the final release is.

If all goes well, this patch will be converted to the next main release on 2021-04-12.

To build 5.4.109-rt56-rc1 directly, the following patches should be applied:

https://www.kernel.org/pub/linux/kernel/v5.x/linux-5.4.tar.xz

https://www.kernel.org/pub/linux/kernel/v5.x/patch-5.4.109.xz

https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/patch-5.4.109-rt56-rc1.patch.xz

You can also build from 5.4.109-rt55 by applying the incremental patch:

https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/incr/patch-5.4.109-rt55-rt56-rc1.patch.xz

Enjoy,

-- Tom

Sebastian Andrzej Siewior (1):
mm: slub: Don't resize the location tracking cache on PREEMPT_RT

Tom Zanussi (1):
Linux 5.4.109-rt56-rc1

 localversion-rt | 2 +-
 mm/slub.c       | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

2.17.1

From: Sebastian Andrzej Siewior <[email protected]>

v5.4.109-rt56-rc1 stable review patch.
If anyone has any objections, please let me know.

-----------

[ Upstream commit 87bd0bf324f4c5468ea3d1de0482589f491f3145 ]

The location tracking cache has a size of a page and is resized if its current size is too small.
This allocation happens with disabled interrupts and can't happen on PREEMPT_RT.
Should one page be too small, then we have to allocate more at the beginning. The only downside is that less callers will be visible.

---
 mm/slub.c | 3 +++
 1 file changed, 3 insertions(+)

index 1815e28852fe..0d78368d149a 100644
@@ -4647,6 +4647,9 @@ static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
 	struct location *l;
 	int order;
 
+	if (IS_ENABLED(CONFIG_PREEMPT_RT) && flags == GFP_ATOMIC)
+		return 0;
+
 	order = get_order(sizeof(struct location) * max);
 
 	l = (void *)__get_free_pages(flags, order);

2.17.1

From: Tom Zanussi <[email protected]>

v5.4.109-rt56-rc1 stable review patch.
If anyone has any objections, please let me know.

-----------

---
 localversion-rt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 51b05e9abe6f..a6adf38a57d4 100644
@@ -1 +1 @@
--rt55
+-rt56-rc1

2.17.1