Messages in this thread Patch in this message | | | From | Johannes Weiner <> | Subject | [rfc patch 1/3] mm: always pass mapping in zap_details | Date | Wed, 30 Sep 2009 23:09:22 +0200 |
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Currently, unmap_mapping_range() only fills in the address space information in zap details when it wants to filter private COW pages and the zapping loops need to compare page->mapping against it.
For unmapping private COW pages on truncation, we will need this information also in the opposite case to filter shared pages.
Demux this one check_mapping member by adding an explicit mode flag and always pass along the address space.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> --- include/linux/mm.h | 3 ++- mm/memory.c | 11 ++++++----- 2 files changed, 8 insertions(+), 6 deletions(-)
--- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -732,7 +732,8 @@ extern void user_shm_unlock(size_t, stru */ struct zap_details { struct vm_area_struct *nonlinear_vma; /* Check page->index if set */ - struct address_space *check_mapping; /* Check page->mapping if set */ + struct address_space *mapping; /* Backing address space */ + bool keep_private; /* Do not touch private pages */ pgoff_t first_index; /* Lowest page->index to unmap */ pgoff_t last_index; /* Highest page->index to unmap */ spinlock_t *i_mmap_lock; /* For unmap_mapping_range: */ --- a/mm/memory.c +++ b/mm/memory.c @@ -824,8 +824,8 @@ static unsigned long zap_pte_range(struc * invalidate cache without truncating: * unmap shared but keep private pages. */ - if (details->check_mapping && - details->check_mapping != page->mapping) + if (details->keep_private && + details->mapping != page->mapping) continue; /* * Each page->index must be checked when @@ -863,7 +863,7 @@ static unsigned long zap_pte_range(struc continue; } /* - * If details->check_mapping, we leave swap entries; + * If details->keep_private, we leave swap entries; * if details->nonlinear_vma, we leave file entries. */ if (unlikely(details)) @@ -936,7 +936,7 @@ static unsigned long unmap_page_range(st pgd_t *pgd; unsigned long next; - if (details && !details->check_mapping && !details->nonlinear_vma) + if (details && !details->keep_private && !details->nonlinear_vma) details = NULL; BUG_ON(addr >= end); @@ -2433,7 +2433,8 @@ void unmap_mapping_range(struct address_ hlen = ULONG_MAX - hba + 1; } - details.check_mapping = even_cows? NULL: mapping; + details.mapping = mapping; + details.keep_private = !even_cows; details.nonlinear_vma = NULL; details.first_index = hba; details.last_index = hba + hlen - 1;
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