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From: Leonardo Bras <leonardo@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Cc: Leonardo Bras <leonardo@linux.ibm.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Arnd Bergmann <arnd@arndb.de>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	Andrew Morton <akpm@linux-foundation.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Richard Fontana <rfontana@redhat.com>,
	Ganesh Goudar <ganeshgr@linux.ibm.com>,
	Allison Randal <allison@lohutok.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Mike Rapoport <rppt@linux.ibm.com>,
	YueHaibing <yuehaibing@huawei.com>,
	Ira Weiny <ira.weiny@intel.com>, Jason Gunthorpe <jgg@ziepe.ca>,
	John Hubbard <jhubbard@nvidia.com>,
	Keith Busch <keith.busch@intel.com>
Subject: [PATCH v2 03/11] mm/gup: Applies counting method to monitor gup_pgd_range
Date: Fri, 20 Sep 2019 16:50:39 -0300	[thread overview]
Message-ID: <20190920195047.7703-4-leonardo@linux.ibm.com> (raw)
In-Reply-To: <20190920195047.7703-1-leonardo@linux.ibm.com>

As decribed, gup_pgd_range is a lockless pagetable walk. So, in order to
monitor against THP split/collapse with the couting method, it's necessary
to bound it with {start,end}_lockless_pgtbl_walk.

There are dummy functions, so it is not going to add any overhead on archs
that don't use this method.

Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
---
 mm/gup.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index 98f13ab37bac..675e4be27082 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2404,6 +2404,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages,
 			unsigned int gup_flags, struct page **pages)
 {
 	unsigned long addr, len, end;
+	struct mm_struct *mm;
 	int nr = 0, ret = 0;
 
 	if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM)))
@@ -2421,9 +2422,12 @@ int get_user_pages_fast(unsigned long start, int nr_pages,
 
 	if (IS_ENABLED(CONFIG_HAVE_FAST_GUP) &&
 	    gup_fast_permitted(start, end)) {
+		mm = current->mm;
+		start_lockless_pgtbl_walk(mm);
 		local_irq_disable();
 		gup_pgd_range(addr, end, gup_flags, pages, &nr);
 		local_irq_enable();
+		end_lockless_pgtbl_walk(mm);
 		ret = nr;
 	}
 
-- 
2.20.1


WARNING: multiple messages have this Message-ID (diff)
From: Leonardo Bras <leonardo@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Cc: Keith Busch <keith.busch@intel.com>,
	Richard Fontana <rfontana@redhat.com>,
	Paul Mackerras <paulus@samba.org>,
	Ira Weiny <ira.weiny@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	YueHaibing <yuehaibing@huawei.com>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Ganesh Goudar <ganeshgr@linux.ibm.com>,
	Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>,
	Leonardo Bras <leonardo@linux.ibm.com>,
	Arnd Bergmann <arnd@arndb.de>, John Hubbard <jhubbard@nvidia.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Allison Randal <allison@lohutok.net>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH v2 03/11] mm/gup: Applies counting method to monitor gup_pgd_range
Date: Fri, 20 Sep 2019 16:50:39 -0300	[thread overview]
Message-ID: <20190920195047.7703-4-leonardo@linux.ibm.com> (raw)
In-Reply-To: <20190920195047.7703-1-leonardo@linux.ibm.com>

As decribed, gup_pgd_range is a lockless pagetable walk. So, in order to
monitor against THP split/collapse with the couting method, it's necessary
to bound it with {start,end}_lockless_pgtbl_walk.

There are dummy functions, so it is not going to add any overhead on archs
that don't use this method.

Signed-off-by: Leonardo Bras <leonardo@linux.ibm.com>
---
 mm/gup.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index 98f13ab37bac..675e4be27082 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2404,6 +2404,7 @@ int get_user_pages_fast(unsigned long start, int nr_pages,
 			unsigned int gup_flags, struct page **pages)
 {
 	unsigned long addr, len, end;
+	struct mm_struct *mm;
 	int nr = 0, ret = 0;
 
 	if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM)))
@@ -2421,9 +2422,12 @@ int get_user_pages_fast(unsigned long start, int nr_pages,
 
 	if (IS_ENABLED(CONFIG_HAVE_FAST_GUP) &&
 	    gup_fast_permitted(start, end)) {
+		mm = current->mm;
+		start_lockless_pgtbl_walk(mm);
 		local_irq_disable();
 		gup_pgd_range(addr, end, gup_flags, pages, &nr);
 		local_irq_enable();
+		end_lockless_pgtbl_walk(mm);
 		ret = nr;
 	}
 
-- 
2.20.1


  parent reply	other threads:[~2019-09-20 19:52 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-20 19:50 [PATCH v2 00/11] Introduces new count-based method for monitoring lockless pagetable wakls Leonardo Bras
2019-09-20 19:50 ` Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 01/11] powerpc/mm: Adds counting method to monitor lockless pgtable walks Leonardo Bras
2019-09-20 19:50   ` Leonardo Bras
2019-09-23 20:42   ` John Hubbard
2019-09-23 20:42     ` John Hubbard
2019-09-23 20:50     ` Leonardo Bras
2019-09-23 20:50       ` Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 02/11] asm-generic/pgtable: Adds dummy functions " Leonardo Bras
2019-09-20 19:50   ` Leonardo Bras
2019-09-23 20:39   ` John Hubbard
2019-09-23 20:39     ` John Hubbard
2019-09-23 20:48     ` Leonardo Bras
2019-09-23 20:48       ` Leonardo Bras
2019-09-23 20:53       ` John Hubbard
2019-09-23 20:53         ` John Hubbard
2019-09-20 19:50 ` Leonardo Bras [this message]
2019-09-20 19:50   ` [PATCH v2 03/11] mm/gup: Applies counting method to monitor gup_pgd_range Leonardo Bras
2019-09-23 20:27   ` John Hubbard
2019-09-23 20:27     ` John Hubbard
2019-09-23 21:01     ` Leonardo Bras
2019-09-23 21:01       ` Leonardo Bras
2019-09-23 21:09       ` John Hubbard
2019-09-23 21:09         ` John Hubbard
2019-09-20 19:50 ` [PATCH v2 04/11] powerpc/mce_power: Applies counting method to monitor lockless pgtbl walks Leonardo Bras
2019-09-20 19:50   ` Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 05/11] powerpc/perf: " Leonardo Bras
2019-09-20 19:50   ` Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 06/11] powerpc/mm/book3s64/hash: " Leonardo Bras
2019-09-20 19:50   ` Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 07/11] powerpc/kvm/e500: " Leonardo Bras
2019-09-20 19:50   ` Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 08/11] powerpc/kvm/book3s_hv: " Leonardo Bras
2019-09-20 19:50   ` Leonardo Bras
2019-09-23 20:47   ` John Hubbard
2019-09-23 20:47     ` John Hubbard
2019-09-20 19:50 ` [PATCH v2 09/11] powerpc/kvm/book3s_64: " Leonardo Bras
2019-09-20 19:50   ` Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 10/11] powerpc/book3s_64: Enables counting method to monitor lockless pgtbl walk Leonardo Bras
2019-09-20 19:50   ` Leonardo Bras
2019-09-20 19:50 ` [PATCH v2 11/11] powerpc/mm/book3s64/pgtable: Uses counting method to skip serializing Leonardo Bras
2019-09-20 19:50   ` Leonardo Bras
2019-09-20 20:11   ` John Hubbard
2019-09-20 20:28     ` Leonardo Bras
2019-09-20 20:28       ` Leonardo Bras
2019-09-20 21:15       ` John Hubbard
2019-09-21  0:48       ` John Hubbard
2019-09-21  0:48         ` John Hubbard
2019-09-23 17:25         ` Leonardo Bras
2019-09-23 17:25           ` Leonardo Bras
2019-09-23 18:14           ` John Hubbard
2019-09-23 18:14             ` John Hubbard
2019-09-23 19:40             ` Leonardo Bras
2019-09-23 19:40               ` Leonardo Bras
2019-09-23 19:58               ` John Hubbard
2019-09-23 19:58                 ` John Hubbard
2019-09-23 20:23                 ` Leonardo Bras
2019-09-23 20:23                   ` Leonardo Bras
2019-09-23 20:26                   ` John Hubbard
2019-09-23 20:26                     ` John Hubbard
2019-09-20 19:56 ` [PATCH v2 00/11] Introduces new count-based method for monitoring lockless pagetable wakls Leonardo Bras
2019-09-20 19:56   ` Leonardo Bras
2019-09-20 20:12 ` Leonardo Bras
2019-09-20 20:12   ` Leonardo Bras
2019-09-20 21:24   ` John Hubbard
2019-09-20 21:24     ` John Hubbard
2019-09-23 20:51   ` John Hubbard
2019-09-23 20:51     ` John Hubbard
2019-09-23 20:58     ` Leonardo Bras
2019-09-23 20:58       ` Leonardo Bras

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