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mm: introduce page_vma_mapped_walk()

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Introduce a new interface to check if a page is mapped into a vma.  It
aims to address shortcomings of page_check_address{,_transhuge}.

Existing interface is not able to handle PTE-mapped THPs: it only finds
the first PTE.  The rest lefted unnoticed.

page_vma_mapped_walk() iterates over all possible mapping of the page in
the vma.

Link: http://lkml.kernel.org/r/20170129173858.45174-3-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov
2017-02-24 14:57:45 -08:00
committed by Linus Torvalds
parent c8394812e5
commit ace71a19ce
4 changed files with 224 additions and 5 deletions
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26
include/linux/rmap.h
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@@ -9,6 +9,7 @@
#include <linux/mm.h>
#include <linux/rwsem.h>
#include <linux/memcontrol.h>
#include <linux/highmem.h>
/*
* The anon_vma heads a list of private "related" vmas, to scan if
@@ -232,6 +233,31 @@ static inline bool page_check_address_transhuge(struct page *page,
}
#endif
/* Avoid racy checks */
#define PVMW_SYNC (1 << 0)
/* Look for migarion entries rather than present PTEs */
#define PVMW_MIGRATION (1 << 1)
struct page_vma_mapped_walk {
struct page *page;
struct vm_area_struct *vma;
unsigned long address;
pmd_t *pmd;
pte_t *pte;
spinlock_t *ptl;
unsigned int flags;
};
static inline void page_vma_mapped_walk_done(struct page_vma_mapped_walk *pvmw)
{
if (pvmw->pte)
pte_unmap(pvmw->pte);
if (pvmw->ptl)
spin_unlock(pvmw->ptl);
}
bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw);
/*
* Used by swapoff to help locate where page is expected in vma.
*/