Re: [PATCH v6 5/7] mm: make tlb_flush_pending global

Minchan Kim
2017-08-02T23:23:20Z

On Wed, Aug 02, 2017 at 10:28:47PM +0800, kbuild test robot wrote:
> Hi Minchan,
>
> [auto build test WARNING on linus/master]
> [also build test WARNING on v4.13-rc3]
> [cannot apply to next-20170802]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url: https://github.com/0day-ci/linux/commits/Nadav-Amit/mm-migrate-prevent-racy-access-to-tlb_flush_pending/20170802-205715
> config: sh-allyesconfig (attached as .config)
> compiler: sh4-linux-gnu-gcc (Debian 6.1.1-9) 6.1.1 20160705
> reproduce:
> wget https://raw.githubusercontent.com/01org/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # save the attached .config to linux build tree
> make.cross ARCH=sh
>
> All warnings (new ones prefixed by >>):
>
> In file included from include/linux/printk.h:6:0,
> from include/linux/kernel.h:13,
> from mm/debug.c:8:
> mm/debug.c: In function 'dump_mm':
> >> include/linux/kern_levels.h:4:18: warning: format '%lx' expects argument of type 'long unsigned int', but argument 40 has type 'int' [-Wformat=]

Thanks. lkp.

This patch should fix it.

>From 5be44c3cbe0e4149cc8b438f2e3fcad046091a29 Mon Sep 17 00:00:00 2001
From: Minchan Kim <minchan@kernel.org>
Date: Tue, 1 Aug 2017 14:04:58 +0900
Subject: [PATCH v6 5/7] mm: make tlb_flush_pending global

Currently, tlb_flush_pending is used only for CONFIG_[NUMA_BALANCING|
COMPACTION] but upcoming patches to solve subtle TLB flush bacting
problem will use it regardless of compaction/numa so this patch
doesn't remove the dependency.

Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
include/linux/mm_types.h | 21 ---------------------
mm/debug.c | 4 ----
2 files changed, 25 deletions(-)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index c605f2a3a68e..892a7b0196fd 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -487,14 +487,12 @@ struct mm_struct {
/* numa_scan_seq prevents two threads setting pte_numa */
int numa_scan_seq;
#endif
-#if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
/*
* An operation with batched TLB flushing is going on. Anything that
* can move process memory needs to flush the TLB when moving a
* PROT_NONE or PROT_NUMA mapped page.
*/
atomic_t tlb_flush_pending;
-#endif
#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH
/* See flush_tlb_batched_pending() */
bool tlb_flush_batched;
@@ -528,7 +526,6 @@ extern void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
extern void tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end);

-#if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
/*
* Memory barriers to keep this state in sync are graciously provided by
* the page table locks, outside of which no page table modifications happen.
@@ -569,24 +566,6 @@ static inline void dec_tlb_flush_pending(struct mm_struct *mm)
smp_mb__before_atomic();
atomic_dec(&mm->tlb_flush_pending);
}
-#else
-static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
-{
- return false;
-}
-
-static inline void init_tlb_flush_pending(struct mm_struct *mm)
-{
-}
-
-static inline void inc_tlb_flush_pending(struct mm_struct *mm)
-{
-}
-
-static inline void dec_tlb_flush_pending(struct mm_struct *mm)
-{
-}
-#endif

struct vm_fault;

diff --git a/mm/debug.c b/mm/debug.c
index d70103bb4731..5715448ab0b5 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -124,9 +124,7 @@ void dump_mm(const struct mm_struct *mm)
#ifdef CONFIG_NUMA_BALANCING
"numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
#endif
-#if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
"tlb_flush_pending %d\n"
-#endif
"def_flags: %#lx(%pGv)\n",

mm, mm->mmap, mm->vmacache_seqnum, mm->task_size,
@@ -158,9 +156,7 @@ void dump_mm(const struct mm_struct *mm)
#ifdef CONFIG_NUMA_BALANCING
mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
#endif
-#if defined(CONFIG_NUMA_BALANCING) || defined(CONFIG_COMPACTION)
atomic_read(&mm->tlb_flush_pending),
-#endif
mm->def_flags, &mm->def_flags
);
}
--
2.7.4