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authorSteven Price <steven.price@arm.com>2020-02-04 04:35:45 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-02-04 06:05:25 +0300
commit3afc423632a194d7d6afef34e4bb98f804cd071d (patch)
treed72ce1e5013f4c6588424e1e7ac4f7997bbdeb52 /mm/pagewalk.c
parent757b2a4ab560b84d1859cfdfb9c7489af4ef5fd6 (diff)
downloadlinux-3afc423632a194d7d6afef34e4bb98f804cd071d.tar.xz
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.c50
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;