The patch titled
memcg-remove-direct-page_cgroup-to-page-pointer-fix-fix
has been added to the -mm tree. Its filename is
memcg-remove-direct-page_cgroup-to-page-pointer-fix-fix.patch
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See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memcg-remove-direct-page_cgroup-to-page-pointer-fix-fix
From: Johannes Weiner <hannes@xxxxxxxxxxx>
include/linux/page_cgroup.h:144: warning: left shift count >= width of type
include/linux/page_cgroup.h:145: warning: left shift count >= width of type
include/linux/page_cgroup.h:150: warning: right shift count >= width of type
Since the non-flags field for pc array ids in pc->flags is offset from the
end of the word, we end up with a shift count of BITS_PER_LONG in case the
field width is zero.
This results in a compiler warning as we shift in both directions a long
int by BITS_PER_LONG.
There is no real harm -- the mask is zero -- but fix up the compiler
warning by also making the shift count zero for a non-existant field.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reported-by: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/page_cgroup.h | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
diff -puN include/linux/page_cgroup.h~memcg-remove-direct-page_cgroup-to-page-pointer-fix-fix include/linux/page_cgroup.h
--- a/include/linux/page_cgroup.h~memcg-remove-direct-page_cgroup-to-page-pointer-fix-fix
+++ a/include/linux/page_cgroup.h
@@ -123,31 +123,36 @@ static inline void move_unlock_page_cgro
}
#ifdef CONFIG_SPARSEMEM
-#define PCG_ARRAYID_SHIFT SECTIONS_SHIFT
+#define PCG_ARRAYID_WIDTH SECTIONS_SHIFT
#else
-#define PCG_ARRAYID_SHIFT NODES_SHIFT
+#define PCG_ARRAYID_WIDTH NODES_SHIFT
#endif
-#if (PCG_ARRAYID_SHIFT > BITS_PER_LONG - NR_PCG_FLAGS)
+#if (PCG_ARRAYID_WIDTH > BITS_PER_LONG - NR_PCG_FLAGS)
#error Not enough space left in pc->flags to store page_cgroup array IDs
#endif
/* pc->flags: ARRAY-ID | FLAGS */
-#define PCG_ARRAYID_MASK ((1UL << PCG_ARRAYID_SHIFT) - 1)
+#define PCG_ARRAYID_MASK ((1UL << PCG_ARRAYID_WIDTH) - 1)
-#define PCG_ARRAYID_OFFSET (sizeof(unsigned long) * 8 - PCG_ARRAYID_SHIFT)
+#define PCG_ARRAYID_OFFSET (BITS_PER_LONG - PCG_ARRAYID_WIDTH)
+/*
+ * Zero the shift count for non-existant fields, to prevent compiler
+ * warnings and ensure references are optimized away.
+ */
+#define PCG_ARRAYID_SHIFT (PCG_ARRAYID_OFFSET * (PCG_ARRAYID_WIDTH != 0))
static inline void set_page_cgroup_array_id(struct page_cgroup *pc,
unsigned long id)
{
- pc->flags &= ~(PCG_ARRAYID_MASK << PCG_ARRAYID_OFFSET);
- pc->flags |= (id & PCG_ARRAYID_MASK) << PCG_ARRAYID_OFFSET;
+ pc->flags &= ~(PCG_ARRAYID_MASK << PCG_ARRAYID_SHIFT);
+ pc->flags |= (id & PCG_ARRAYID_MASK) << PCG_ARRAYID_SHIFT;
}
static inline unsigned long page_cgroup_array_id(struct page_cgroup *pc)
{
- return (pc->flags >> PCG_ARRAYID_OFFSET) & PCG_ARRAYID_MASK;
+ return (pc->flags >> PCG_ARRAYID_SHIFT) & PCG_ARRAYID_MASK;
}
#else /* CONFIG_CGROUP_MEM_RES_CTLR */
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
origin.patch
mm-introduce-delete_from_page_cache.patch
mm-hugetlbfs-change-remove_from_page_cache.patch
mm-shmem-change-remove_from_page_cache.patch
mm-truncate-change-remove_from_page_cache.patch
mm-good-bye-remove_from_page_cache.patch
mm-change-__remove_from_page_cache.patch
epoll-fix-compiler-warning-and-optimize-the-non-blocking-path-fix.patch
memcg-res_counter_read_u64-fix-potential-races-on-32-bit-machines.patch
memcg-fix-ugly-initialization-of-return-value-is-in-caller.patch
memcg-soft-limit-reclaim-should-end-at-limit-not-below.patch
memcg-simplify-the-way-memory-limits-are-checked.patch
memcg-remove-unused-page-flag-bitfield-defines.patch
memcg-remove-impossible-conditional-when-committing.patch
memcg-remove-null-check-from-lookup_page_cgroup-result.patch
memcg-add-memcg-sanity-checks-at-allocating-and-freeing-pages.patch
memcg-add-memcg-sanity-checks-at-allocating-and-freeing-pages-update.patch
memcg-no-uncharged-pages-reach-page_cgroup_zoneinfo.patch
memcg-change-page_cgroup_zoneinfo-signature.patch
memcg-fold-__mem_cgroup_move_account-into-caller.patch
memcg-condense-page_cgroup-to-page-lookup-points.patch
memcg-remove-direct-page_cgroup-to-page-pointer.patch
memcg-remove-direct-page_cgroup-to-page-pointer-fix.patch
memcg-remove-direct-page_cgroup-to-page-pointer-fix-fix.patch
crash_dump-export-is_kdump_kernel-to-modules-consolidate-elfcorehdr_addr-setup_elfcorehdr-and-saved_max_pfn.patch
crash_dump-export-is_kdump_kernel-to-modules-consolidate-elfcorehdr_addr-setup_elfcorehdr-and-saved_max_pfn-fix.patch
crash_dump-export-is_kdump_kernel-to-modules-consolidate-elfcorehdr_addr-setup_elfcorehdr-and-saved_max_pfn-fix-fix.patch
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