diff options
author | Steven Price <steven.price@arm.com> | 2020-02-03 17:35:45 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-02-04 03:05:25 +0000 |
commit | 3afc423632a194d7d6afef34e4bb98f804cd071d (patch) | |
tree | d72ce1e5013f4c6588424e1e7ac4f7997bbdeb52 /mm/pagewalk.c | |
parent | 757b2a4ab560b84d1859cfdfb9c7489af4ef5fd6 (diff) | |
download | linux-3afc423632a194d7d6afef34e4bb98f804cd071d.tar.bz2 |
mm: pagewalk: add p4d_entry() and pgd_entry()
pgd_entry() and pud_entry() were removed by commit 0b1fbfe50006c410
("mm/pagewalk: remove pgd_entry() and pud_entry()") because there were no
users. We're about to add users so reintroduce them, along with
p4d_entry() as we now have 5 levels of tables.
Note that commit a00cc7d9dd93d66a ("mm, x86: add support for PUD-sized
transparent hugepages") already re-added pud_entry() but with different
semantics to the other callbacks. This commit reverts the semantics back
to match the other callbacks.
To support hmm.c which now uses the new semantics of pud_entry() a new
member ('action') of struct mm_walk is added which allows the callbacks to
either descend (ACTION_SUBTREE, the default), skip (ACTION_CONTINUE) or
repeat the callback (ACTION_AGAIN). hmm.c is then updated to call
pud_trans_huge_lock() itself and make use of the splitting/retry logic of
the core code.
After this change pud_entry() is called for all entries, not just
transparent huge pages.
[arnd@arndb.de: fix unused variable warning]
Link: http://lkml.kernel.org/r/20200107204607.1533842-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20191218162402.45610-12-steven.price@arm.com
Signed-off-by: Steven Price <steven.price@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: "Liang, Kan" <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Cc: Zong Li <zong.li@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/pagewalk.c')
-rw-r--r-- | mm/pagewalk.c | 50 |
1 files changed, 35 insertions, 15 deletions
diff --git a/mm/pagewalk.c b/mm/pagewalk.c index ea0b9e606ad1..690af44609e2 100644 --- a/mm/pagewalk.c +++ b/mm/pagewalk.c @@ -46,6 +46,9 @@ again: break; continue; } + + walk->action = ACTION_SUBTREE; + /* * This implies that each ->pmd_entry() handler * needs to know about pmd_trans_huge() pmds @@ -55,16 +58,21 @@ again: if (err) break; + if (walk->action == ACTION_AGAIN) + goto again; + /* * Check this here so we only break down trans_huge * pages when we _need_ to */ - if (!ops->pte_entry) + if (walk->action == ACTION_CONTINUE || + !(ops->pte_entry)) continue; split_huge_pmd(walk->vma, pmd, addr); if (pmd_trans_unstable(pmd)) goto again; + err = walk_pte_range(pmd, addr, next, walk); if (err) break; @@ -93,24 +101,25 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, continue; } - if (ops->pud_entry) { - spinlock_t *ptl = pud_trans_huge_lock(pud, walk->vma); + walk->action = ACTION_SUBTREE; - if (ptl) { - err = ops->pud_entry(pud, addr, next, walk); - spin_unlock(ptl); - if (err) - break; - continue; - } - } + if (ops->pud_entry) + err = ops->pud_entry(pud, addr, next, walk); + if (err) + break; + + if (walk->action == ACTION_AGAIN) + goto again; + + if (walk->action == ACTION_CONTINUE || + !(ops->pmd_entry || ops->pte_entry)) + continue; split_huge_pud(walk->vma, pud, addr); if (pud_none(*pud)) goto again; - if (ops->pmd_entry || ops->pte_entry) - err = walk_pmd_range(pud, addr, next, walk); + err = walk_pmd_range(pud, addr, next, walk); if (err) break; } while (pud++, addr = next, addr != end); @@ -136,7 +145,12 @@ static int walk_p4d_range(pgd_t *pgd, unsigned long addr, unsigned long end, break; continue; } - if (ops->pmd_entry || ops->pte_entry) + if (ops->p4d_entry) { + err = ops->p4d_entry(p4d, addr, next, walk); + if (err) + break; + } + if (ops->pud_entry || ops->pmd_entry || ops->pte_entry) err = walk_pud_range(p4d, addr, next, walk); if (err) break; @@ -163,7 +177,13 @@ static int walk_pgd_range(unsigned long addr, unsigned long end, break; continue; } - if (ops->pmd_entry || ops->pte_entry) + if (ops->pgd_entry) { + err = ops->pgd_entry(pgd, addr, next, walk); + if (err) + break; + } + if (ops->p4d_entry || ops->pud_entry || ops->pmd_entry || + ops->pte_entry) err = walk_p4d_range(pgd, addr, next, walk); if (err) break; |