On 1/27/20 1:41 PM, Peter Zijlstra wrote:
On Sun, Jan 26, 2020 at 07:52:05AM -0800, Guenter Roeck wrote:
On Thu, Dec 12, 2019 at 10:32:05AM +0100, Peter Zijlstra wrote:
As described in the comment, the correct order for freeing pages is:
1) unhook page
2) TLB invalidate page
3) free page
This order equally applies to page directories.
Currently there are two correct options:
- use tlb_remove_page(), when all page directores are full pages and
there are no futher contraints placed by things like software
walkers (HAVE_FAST_GUP).
- use MMU_GATHER_RCU_TABLE_FREE and tlb_remove_table() when the
architecture does not do IPI based TLB invalidate and has
HAVE_FAST_GUP (or software TLB fill).
This however leaves architectures that don't have page based
directories but don't need RCU in a bind. For those, provide
MMU_GATHER_TABLE_FREE, which provides the independent batching for
directories without the additional RCU freeing.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
Various sparc64 builds (allnoconfig, tinyconfig, as well as builds
with SMP disabled):
mm/mmu_gather.c: In function '__tlb_remove_table_free':
mm/mmu_gather.c:101:3: error: implicit declaration of function '__tlb_remove_table'; did you mean 'tlb_remove_table'?
Thanks; I'll respin these patches against Aneesh' pile and make sure to
look into this when I do so.
I did send a change to fix that. it is to drop !SMP change in the patch
https://lore.kernel.org/linux-mm/87v9p9mhnr.fsf@xxxxxxxxxxxxx
-aneesh
