[PATCH] mm: tlb_finish_mmu forget rss
zap_pte_range has been counting the pages it frees in tlb->freed, then
tlb_finish_mmu has used that to update the mm's rss. That got stranger when I
added anon_rss, yet updated it by a different route; and stranger when rss and
anon_rss became mm_counters with special access macros. And it would no
longer be viable if we're relying on page_table_lock to stabilize the
mm_counter, but calling tlb_finish_mmu outside that lock.
Remove the mmu_gather's freed field, let tlb_finish_mmu stick to its own
business, just decrement the rss mm_counter in zap_pte_range (yes, there was
some point to batching the update, and a subsequent patch restores that). And
forget the anal paranoia of first reading the counter to avoid going negative
- if rss does go negative, just fix that bug.
Remove the mmu_gather's flushes and avoided_flushes from arm and arm26: no use
was being made of them. But arm26 alone was actually using the freed, in the
way some others use need_flush: give it a need_flush. arm26 seems to prefer
spaces to tabs here: respect that.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-arm/tlb.h b/include/asm-arm/tlb.h
index a35ab0f..f49bfb7 100644
--- a/include/asm-arm/tlb.h
+++ b/include/asm-arm/tlb.h
@@ -27,11 +27,7 @@
*/
struct mmu_gather {
struct mm_struct *mm;
- unsigned int freed;
unsigned int fullmm;
-
- unsigned int flushes;
- unsigned int avoided_flushes;
};
DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
@@ -42,7 +38,6 @@
struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
tlb->mm = mm;
- tlb->freed = 0;
tlb->fullmm = full_mm_flush;
return tlb;
@@ -51,16 +46,8 @@
static inline void
tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
{
- struct mm_struct *mm = tlb->mm;
- unsigned long freed = tlb->freed;
- int rss = get_mm_counter(mm, rss);
-
- if (rss < freed)
- freed = rss;
- add_mm_counter(mm, rss, -freed);
-
if (tlb->fullmm)
- flush_tlb_mm(mm);
+ flush_tlb_mm(tlb->mm);
/* keep the page table cache within bounds */
check_pgt_cache();