From mboxrd@z Thu Jan 1 00:00:00 1970 From: Leonardo Bras Date: Fri, 27 Sep 2019 23:40:01 +0000 Subject: [PATCH v4 04/11] powerpc/mce_power: Applies counting method to monitor lockless pgtbl walks Message-Id: <20190927234008.11513-5-leonardo@linux.ibm.com> List-Id: References: <20190927234008.11513-1-leonardo@linux.ibm.com> In-Reply-To: <20190927234008.11513-1-leonardo@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org Cc: Leonardo Bras , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Arnd Bergmann , "Aneesh Kumar K.V" , Christophe Leroy , Andrew Morton , Dan Williams , Nicholas Piggin , Mahesh Salgaonkar , Allison Randal , Thomas Gleixner , Ganesh Goudar , Mike Rapoport , YueHaibing , Greg Kroah-Hartman , Ira Weiny , Jason Gunthorpe , John Hubbard , Keith Busch Applies the counting-based method for monitoring lockless pgtable walks on addr_to_pfn(). Signed-off-by: Leonardo Bras --- arch/powerpc/kernel/mce_power.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c index a814d2dfb5b0..0f2f87da4cd1 100644 --- a/arch/powerpc/kernel/mce_power.c +++ b/arch/powerpc/kernel/mce_power.c @@ -27,6 +27,7 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr) { pte_t *ptep; unsigned long flags; + unsigned long pfn; struct mm_struct *mm; if (user_mode(regs)) @@ -34,15 +35,21 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr) else mm = &init_mm; + start_lockless_pgtbl_walk(mm); local_irq_save(flags); if (mm = current->mm) ptep = find_current_mm_pte(mm->pgd, addr, NULL, NULL); else ptep = find_init_mm_pte(addr, NULL); - local_irq_restore(flags); + if (!ptep || pte_special(*ptep)) - return ULONG_MAX; - return pte_pfn(*ptep); + pfn = ULONG_MAX; + else + pfn = pte_pfn(*ptep); + + local_irq_restore(flags); + end_lockless_pgtbl_walk(mm); + return pfn; } /* flush SLBs and reload */ -- 2.20.1