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[PATCH] mm: tlb_finish_mmu forget rss

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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>
This commit is contained in:
Hugh Dickins
2005-10-29 18:16:03 -07:00
committed by Linus Torvalds
parent 4d6ddfa924
commit fc2acab31b
7 changed files with 18 additions and 69 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
include/asm-ia64/tlb.h
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@@ -60,7 +60,6 @@ struct mmu_gather {
unsigned int nr; /* == ~0U => fast mode */
unsigned char fullmm; /* non-zero means full mm flush */
unsigned char need_flush; /* really unmapped some PTEs? */
unsigned long freed; /* number of pages freed */
unsigned long start_addr;
unsigned long end_addr;
struct page *pages[FREE_PTE_NR];
@@ -147,7 +146,6 @@ tlb_gather_mmu (struct mm_struct *mm, unsigned int full_mm_flush)
*/
tlb->nr = (num_online_cpus() == 1) ? ~0U : 0;
tlb->fullmm = full_mm_flush;
tlb->freed = 0;
tlb->start_addr = ~0UL;
return tlb;
}
@@ -159,13 +157,6 @@ tlb_gather_mmu (struct mm_struct *mm, unsigned int full_mm_flush)
static inline void
tlb_finish_mmu (struct mmu_gather *tlb, unsigned long start, unsigned long end)
{
unsigned long freed = tlb->freed;
struct mm_struct *mm = tlb->mm;
unsigned long rss = get_mm_counter(mm, rss);
if (rss < freed)
freed = rss;
add_mm_counter(mm, rss, -freed);
/*
* Note: tlb->nr may be 0 at this point, so we can't rely on tlb->start_addr and
* tlb->end_addr.