Subject: [to-be-updated] mm-use-the-light-version-__mod_zone_page_state-in-mlocked_vma_newpage.patch removed from -mm tree
To: nasa4836@xxxxxxxxx,akpm@xxxxxxxxxxxxxxxxxxxx,cl@xxxxxxxxx,hughd@xxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 14 May 2014 13:28:00 -0700
The patch titled
Subject: mm: use the light version __mod_zone_page_state in mlocked_vma_newpage()
has been removed from the -mm tree. Its filename was
mm-use-the-light-version-__mod_zone_page_state-in-mlocked_vma_newpage.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Jianyu Zhan <nasa4836@xxxxxxxxx>
Subject: mm: use the light version __mod_zone_page_state in mlocked_vma_newpage()
mlocked_vma_newpage() is called with pte lock held(a spinlock), which
implies preemtion disabled, and the vm stat counter is not modified from
interrupt context, so we need not use an irq-safe mod_zone_page_state()
here, using a light-weight version __mod_zone_page_state() would be OK.
This patch also documents __mod_zone_page_state() and some of its
callsites. The comment above __mod_zone_page_state() is from Hugh
Dickins, and acked by Christoph.
Most credits to Hugh and Christoph for the clarification on the usage of
the __mod_zone_page_state().
Suggested-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Reviewed-by: Christoph Lameter <cl@xxxxxxxxx>
Signed-off-by: Jianyu Zhan <nasa4836@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/internal.h | 7 ++++++-
mm/rmap.c | 9 +++++++++
mm/vmstat.c | 4 +++-
3 files changed, 18 insertions(+), 2 deletions(-)
diff -puN mm/internal.h~mm-use-the-light-version-__mod_zone_page_state-in-mlocked_vma_newpage mm/internal.h
--- a/mm/internal.h~mm-use-the-light-version-__mod_zone_page_state-in-mlocked_vma_newpage
+++ a/mm/internal.h
@@ -201,7 +201,12 @@ static inline int mlocked_vma_newpage(st
return 0;
if (!TestSetPageMlocked(page)) {
- mod_zone_page_state(page_zone(page), NR_MLOCK,
+ /*
+ * We use the irq-unsafe __mod_zone_page_stat because
+ * this counter is not modified from interrupt context, and the
+ * pte lock is held(spinlock), which implies preemption disabled.
+ */
+ __mod_zone_page_state(page_zone(page), NR_MLOCK,
hpage_nr_pages(page));
count_vm_event(UNEVICTABLE_PGMLOCKED);
}
diff -puN mm/rmap.c~mm-use-the-light-version-__mod_zone_page_state-in-mlocked_vma_newpage mm/rmap.c
--- a/mm/rmap.c~mm-use-the-light-version-__mod_zone_page_state-in-mlocked_vma_newpage
+++ a/mm/rmap.c
@@ -982,6 +982,11 @@ void do_page_add_anon_rmap(struct page *
{
int first = atomic_inc_and_test(&page->_mapcount);
if (first) {
+ /*
+ * We use the irq-unsafe __{inc|mod}_zone_page_stat because
+ * these counters are not modified from interrupt context, and
+ * pte lock(a spinlock) is held, which implies preemption disabled.
+ */
if (PageTransHuge(page))
__inc_zone_page_state(page,
NR_ANON_TRANSPARENT_HUGEPAGES);
@@ -1073,6 +1078,10 @@ void page_remove_rmap(struct page *page)
/*
* Hugepages are not counted in NR_ANON_PAGES nor NR_FILE_MAPPED
* and not charged by memcg for now.
+ *
+ * We use the irq-unsafe __{inc|mod}_zone_page_stat because
+ * these counters are not modified from interrupt context, and
+ * pte lock(a spinlock) is held, which implies preemption disabled.
*/
if (unlikely(PageHuge(page)))
goto out;
diff -puN mm/vmstat.c~mm-use-the-light-version-__mod_zone_page_state-in-mlocked_vma_newpage mm/vmstat.c
--- a/mm/vmstat.c~mm-use-the-light-version-__mod_zone_page_state-in-mlocked_vma_newpage
+++ a/mm/vmstat.c
@@ -207,7 +207,9 @@ void set_pgdat_percpu_threshold(pg_data_
}
/*
- * For use when we know that interrupts are disabled.
+ * For use when we know that interrupts are disabled,
+ * or when we know that preemption is disabled and that
+ * particular counter cannot be updated from interrupt context.
*/
void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item,
int delta)
_
Patches currently in -mm which might be from nasa4836@xxxxxxxxx are
origin.patch
mm-swapc-clean-up-lru_cache_add-functions.patch
mm-swapc-introduce-put_refcounted_compound_page-helpers-for-spliting-put_compound_page.patch
mm-swapc-split-put_compound_page-function.patch
mm-introdule-compound_head_by_tail.patch
mm-memcontrol-clean-up-memcg-zoneinfo-lookup.patch
mm-memcontrol-remove-unnecessary-memcg-argument-from-soft-limit-functions.patch
mm-use-the-light-version-__mod_zone_page_state-in-mlocked_vma_newpage-checkpatch-fixes.patch
mm-fold-mlocked_vma_newpage-into-its-only-call-site.patch
mm-fold-mlocked_vma_newpage-into-its-only-call-site-checkpatch-fixes.patch
linux-next.patch
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