[PATCH 0/2] Various fixes for contigmem

[PATCH 0/2] Various fixes for contigmem

[Tiwei Bie]

Tiwei Bie (2):
  contigmem: free the allocated memory when error occurs
  contigmem: don't zero the pages during each mmap

 lib/librte_eal/bsdapp/contigmem/contigmem.c | 186 ++++++++++++++++++++++++----
 1 file changed, 161 insertions(+), 25 deletions(-)

-- 
2.12.1

[PATCH 1/2] contigmem: free the allocated memory when error occurs

[Tiwei Bie]

Fixes: 764bf26873b9 ("add FreeBSD support")
Cc: stable@dpdk.org

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
---
 lib/librte_eal/bsdapp/contigmem/contigmem.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eal/bsdapp/contigmem/contigmem.c b/lib/librte_eal/bsdapp/contigmem/contigmem.c
index da971debe..03e3e8def 100644
--- a/lib/librte_eal/bsdapp/contigmem/contigmem.c
+++ b/lib/librte_eal/bsdapp/contigmem/contigmem.c
@@ -123,19 +123,21 @@ static int
 contigmem_load()
 {
 	char index_string[8], description[32];
-	int  i;
+	int  i, error = 0;
 
 	if (contigmem_num_buffers > RTE_CONTIGMEM_MAX_NUM_BUFS) {
 		printf("%d buffers requested is greater than %d allowed\n",
 				contigmem_num_buffers, RTE_CONTIGMEM_MAX_NUM_BUFS);
-		return EINVAL;
+		error = EINVAL;
+		goto error;
 	}
 
 	if (contigmem_buffer_size < PAGE_SIZE ||
 			(contigmem_buffer_size & (contigmem_buffer_size - 1)) != 0) {
 		printf("buffer size 0x%lx is not greater than PAGE_SIZE and "
 				"power of two\n", contigmem_buffer_size);
-		return EINVAL;
+		error = EINVAL;
+		goto error;
 	}
 
 	for (i = 0; i < contigmem_num_buffers; i++) {
@@ -145,7 +147,8 @@ contigmem_load()
 
 		if (contigmem_buffers[i] == NULL) {
 			printf("contigmalloc failed for buffer %d\n", i);
-			return ENOMEM;
+			error = ENOMEM;
+			goto error;
 		}
 
 		printf("%2u: virt=%p phys=%p\n", i, contigmem_buffers[i],
@@ -165,6 +168,14 @@ contigmem_load()
 			GID_WHEEL, 0600, "contigmem");
 
 	return 0;
+
+error:
+	for (i = 0; i < contigmem_num_buffers; i++)
+		if (contigmem_buffers[i] != NULL)
+			contigfree(contigmem_buffers[i], contigmem_buffer_size,
+					M_CONTIGMEM);
+
+	return error;
 }
 
 static int
-- 
2.12.1

[PATCH 2/2] contigmem: don't zero the pages during each mmap

[Tiwei Bie]

Don't zero the pages during each mmap. Instead, only zero the pages
when they are not already mmapped. Otherwise, the multi-process
support will be broken, as the pages will be zeroed when secondary
processes map the memory. Besides, track the open and mmap operations
on the cdev, and prevent the module from being unloaded when it is
still in use.

Fixes: 82f931805506 ("contigmem: zero all pages during mmap")
Cc: stable@dpdk.org

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
---
 lib/librte_eal/bsdapp/contigmem/contigmem.c | 173 ++++++++++++++++++++++++----
 1 file changed, 149 insertions(+), 24 deletions(-)

diff --git a/lib/librte_eal/bsdapp/contigmem/contigmem.c b/lib/librte_eal/bsdapp/contigmem/contigmem.c
index 03e3e8def..4779a4fa0 100644
--- a/lib/librte_eal/bsdapp/contigmem/contigmem.c
+++ b/lib/librte_eal/bsdapp/contigmem/contigmem.c
@@ -50,24 +50,37 @@ __FBSDID("$FreeBSD$");
 
 #include <vm/vm.h>
 #include <vm/pmap.h>
+#include <vm/vm_param.h>
 #include <vm/vm_object.h>
 #include <vm/vm_page.h>
 #include <vm/vm_pager.h>
+#include <vm/vm_phys.h>
+
+struct contigmem_buffer {
+	void           *addr;
+	int             refcnt;
+	struct mtx      mtx;
+};
+
+struct contigmem_vm_handle {
+	int             buffer_index;
+};
 
 static int              contigmem_load(void);
 static int              contigmem_unload(void);
 static int              contigmem_physaddr(SYSCTL_HANDLER_ARGS);
 
-static d_mmap_t         contigmem_mmap;
 static d_mmap_single_t  contigmem_mmap_single;
 static d_open_t         contigmem_open;
+static d_close_t        contigmem_close;
 
 static int              contigmem_num_buffers = RTE_CONTIGMEM_DEFAULT_NUM_BUFS;
 static int64_t          contigmem_buffer_size = RTE_CONTIGMEM_DEFAULT_BUF_SIZE;
 
 static eventhandler_tag contigmem_eh_tag;
-static void            *contigmem_buffers[RTE_CONTIGMEM_MAX_NUM_BUFS];
+static struct contigmem_buffer contigmem_buffers[RTE_CONTIGMEM_MAX_NUM_BUFS];
 static struct cdev     *contigmem_cdev = NULL;
+static int              contigmem_refcnt;
 
 TUNABLE_INT("hw.contigmem.num_buffers", &contigmem_num_buffers);
 TUNABLE_QUAD("hw.contigmem.buffer_size", &contigmem_buffer_size);
@@ -78,6 +91,8 @@ SYSCTL_INT(_hw_contigmem, OID_AUTO, num_buffers, CTLFLAG_RD,
 	&contigmem_num_buffers, 0, "Number of contigmem buffers allocated");
 SYSCTL_QUAD(_hw_contigmem, OID_AUTO, buffer_size, CTLFLAG_RD,
 	&contigmem_buffer_size, 0, "Size of each contiguous buffer");
+SYSCTL_INT(_hw_contigmem, OID_AUTO, num_references, CTLFLAG_RD,
+	&contigmem_refcnt, 0, "Number of references to contigmem");
 
 static SYSCTL_NODE(_hw_contigmem, OID_AUTO, physaddr, CTLFLAG_RD, 0,
 	"physaddr");
@@ -114,9 +129,10 @@ MODULE_VERSION(contigmem, 1);
 static struct cdevsw contigmem_ops = {
 	.d_name         = "contigmem",
 	.d_version      = D_VERSION,
-	.d_mmap         = contigmem_mmap,
+	.d_flags        = D_TRACKCLOSE,
 	.d_mmap_single  = contigmem_mmap_single,
 	.d_open         = contigmem_open,
+	.d_close        = contigmem_close,
 };
 
 static int
@@ -124,6 +140,7 @@ contigmem_load()
 {
 	char index_string[8], description[32];
 	int  i, error = 0;
+	void *addr;
 
 	if (contigmem_num_buffers > RTE_CONTIGMEM_MAX_NUM_BUFS) {
 		printf("%d buffers requested is greater than %d allowed\n",
@@ -141,18 +158,20 @@ contigmem_load()
 	}
 
 	for (i = 0; i < contigmem_num_buffers; i++) {
-		contigmem_buffers[i] =
-				contigmalloc(contigmem_buffer_size, M_CONTIGMEM, M_ZERO, 0,
-			BUS_SPACE_MAXADDR, contigmem_buffer_size, 0);
-
-		if (contigmem_buffers[i] == NULL) {
+		addr = contigmalloc(contigmem_buffer_size, M_CONTIGMEM, M_ZERO,
+			0, BUS_SPACE_MAXADDR, contigmem_buffer_size, 0);
+		if (addr == NULL) {
 			printf("contigmalloc failed for buffer %d\n", i);
 			error = ENOMEM;
 			goto error;
 		}
 
-		printf("%2u: virt=%p phys=%p\n", i, contigmem_buffers[i],
-				(void *)pmap_kextract((vm_offset_t)contigmem_buffers[i]));
+		printf("%2u: virt=%p phys=%p\n", i, addr,
+			(void *)pmap_kextract((vm_offset_t)addr));
+
+		mtx_init(&contigmem_buffers[i].mtx, "contigmem", NULL, MTX_DEF);
+		contigmem_buffers[i].addr = addr;
+		contigmem_buffers[i].refcnt = 0;
 
 		snprintf(index_string, sizeof(index_string), "%d", i);
 		snprintf(description, sizeof(description),
@@ -171,9 +190,9 @@ contigmem_load()
 
 error:
 	for (i = 0; i < contigmem_num_buffers; i++)
-		if (contigmem_buffers[i] != NULL)
-			contigfree(contigmem_buffers[i], contigmem_buffer_size,
-					M_CONTIGMEM);
+		if (contigmem_buffers[i].addr != NULL)
+			contigfree(contigmem_buffers[i].addr,
+				contigmem_buffer_size, M_CONTIGMEM);
 
 	return error;
 }
@@ -183,6 +202,9 @@ contigmem_unload()
 {
 	int i;
 
+	if (contigmem_refcnt > 0)
+		return EBUSY;
+
 	if (contigmem_cdev != NULL)
 		destroy_dev(contigmem_cdev);
 
@@ -190,9 +212,9 @@ contigmem_unload()
 		EVENTHANDLER_DEREGISTER(process_exit, contigmem_eh_tag);
 
 	for (i = 0; i < RTE_CONTIGMEM_MAX_NUM_BUFS; i++)
-		if (contigmem_buffers[i] != NULL)
-			contigfree(contigmem_buffers[i], contigmem_buffer_size,
-					M_CONTIGMEM);
+		if (contigmem_buffers[i].addr != NULL)
+			contigfree(contigmem_buffers[i].addr,
+				contigmem_buffer_size, M_CONTIGMEM);
 
 	return 0;
 }
@@ -203,7 +225,7 @@ contigmem_physaddr(SYSCTL_HANDLER_ARGS)
 	uint64_t	physaddr;
 	int		index = (int)(uintptr_t)arg1;
 
-	physaddr = (uint64_t)vtophys(contigmem_buffers[index]);
+	physaddr = (uint64_t)vtophys(contigmem_buffers[index].addr);
 	return sysctl_handle_64(oidp, &physaddr, 0, req);
 }
 
@@ -211,22 +233,118 @@ static int
 contigmem_open(struct cdev *cdev, int fflags, int devtype,
 		struct thread *td)
 {
+
+	atomic_add_int(&contigmem_refcnt, 1);
+
+	return 0;
+}
+
+static int
+contigmem_close(struct cdev *cdev, int fflags, int devtype,
+		struct thread *td)
+{
+
+	atomic_subtract_int(&contigmem_refcnt, 1);
+
 	return 0;
 }
 
 static int
-contigmem_mmap(struct cdev *cdev, vm_ooffset_t offset, vm_paddr_t *paddr,
-		int prot, vm_memattr_t *memattr)
+contigmem_cdev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
+		vm_ooffset_t foff, struct ucred *cred, u_short *color)
 {
+	struct contigmem_vm_handle *vmh = handle;
+	struct contigmem_buffer *buf;
+
+	buf = &contigmem_buffers[vmh->buffer_index];
+
+	atomic_add_int(&contigmem_refcnt, 1);
+
+	mtx_lock(&buf->mtx);
+	if (buf->refcnt == 0)
+		memset(buf->addr, 0, contigmem_buffer_size);
+	buf->refcnt++;
+	mtx_unlock(&buf->mtx);
 
-	*paddr = offset;
 	return 0;
 }
 
+static void
+contigmem_cdev_pager_dtor(void *handle)
+{
+	struct contigmem_vm_handle *vmh = handle;
+	struct contigmem_buffer *buf;
+
+	buf = &contigmem_buffers[vmh->buffer_index];
+
+	mtx_lock(&buf->mtx);
+	buf->refcnt--;
+	mtx_unlock(&buf->mtx);
+
+	free(vmh, M_CONTIGMEM);
+
+	atomic_subtract_int(&contigmem_refcnt, 1);
+}
+
+static int
+contigmem_cdev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
+		vm_page_t *mres)
+{
+	vm_paddr_t paddr;
+	vm_page_t m_paddr, page;
+	vm_memattr_t memattr, memattr1;
+
+	memattr = object->memattr;
+
+	VM_OBJECT_WUNLOCK(object);
+
+	paddr = offset;
+
+	m_paddr = vm_phys_paddr_to_vm_page(paddr);
+	if (m_paddr != NULL) {
+		memattr1 = pmap_page_get_memattr(m_paddr);
+		if (memattr1 != memattr)
+			memattr = memattr1;
+	}
+
+	if (((*mres)->flags & PG_FICTITIOUS) != 0) {
+		/*
+		 * If the passed in result page is a fake page, update it with
+		 * the new physical address.
+		 */
+		page = *mres;
+		VM_OBJECT_WLOCK(object);
+		vm_page_updatefake(page, paddr, memattr);
+	} else {
+		/*
+		 * Replace the passed in reqpage page with our own fake page and
+		 * free up the all of the original pages.
+		 */
+		page = vm_page_getfake(paddr, memattr);
+		VM_OBJECT_WLOCK(object);
+		vm_page_replace_checked(page, object, (*mres)->pindex, *mres);
+		vm_page_lock(*mres);
+		vm_page_free(*mres);
+		vm_page_unlock(*mres);
+		*mres = page;
+	}
+
+	page->valid = VM_PAGE_BITS_ALL;
+
+	return VM_PAGER_OK;
+}
+
+static struct cdev_pager_ops contigmem_cdev_pager_ops = {
+	.cdev_pg_ctor = contigmem_cdev_pager_ctor,
+	.cdev_pg_dtor = contigmem_cdev_pager_dtor,
+	.cdev_pg_fault = contigmem_cdev_pager_fault,
+};
+
 static int
 contigmem_mmap_single(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size,
 		struct vm_object **obj, int nprot)
 {
+	struct contigmem_vm_handle *vmh;
 	uint64_t buffer_index;
 
 	/*
@@ -238,10 +356,17 @@ contigmem_mmap_single(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size,
 	if (buffer_index >= contigmem_num_buffers)
 		return EINVAL;
 
-	memset(contigmem_buffers[buffer_index], 0, contigmem_buffer_size);
-	*offset = (vm_ooffset_t)vtophys(contigmem_buffers[buffer_index]);
-	*obj = vm_pager_allocate(OBJT_DEVICE, cdev, size, nprot, *offset,
-			curthread->td_ucred);
+	if (size > contigmem_buffer_size)
+		return EINVAL;
+
+	vmh = malloc(sizeof(*vmh), M_CONTIGMEM, M_NOWAIT | M_ZERO);
+	if (vmh == NULL)
+		return ENOMEM;
+	vmh->buffer_index = buffer_index;
+
+	*offset = (vm_ooffset_t)vtophys(contigmem_buffers[buffer_index].addr);
+	*obj = cdev_pager_allocate(vmh, OBJT_DEVICE, &contigmem_cdev_pager_ops,
+			size, nprot, *offset, curthread->td_ucred);
 
 	return 0;
 }
-- 
2.12.1

Re: [PATCH 0/2] Various fixes for contigmem

[Richardson, Bruce]

> -----Original Message-----
> From: Bie, Tiwei
> Sent: Tuesday, May 9, 2017 9:47 AM
> To: dev@dpdk.org
> Cc: Richardson, Bruce <bruce.richardson@intel.com>
> Subject: [PATCH 0/2] Various fixes for contigmem
> 
> Tiwei Bie (2):
>   contigmem: free the allocated memory when error occurs
>   contigmem: don't zero the pages during each mmap
> 
>  lib/librte_eal/bsdapp/contigmem/contigmem.c | 186
> ++++++++++++++++++++++++----
>  1 file changed, 161 insertions(+), 25 deletions(-)
> 
These look better solutions than the previous ones for multi-process.

Acked-by: Bruce Richardson <bruce.richardson@intel.com>

Given that this is not a new bug in this release, I don't think we should take the risk of applying the patches this late in the 17.05 release cycle. I therefore suggest that they be merged for 17.08 and once tested in that release, backported to 17.05 stable.

/Bruce

Re: [PATCH 0/2] Various fixes for contigmem

[Tiwei Bie]

On Wed, May 10, 2017 at 10:05:19PM +0800, Richardson, Bruce wrote:
> 
> > -----Original Message-----
> > From: Bie, Tiwei
> > Sent: Tuesday, May 9, 2017 9:47 AM
> > To: dev@dpdk.org
> > Cc: Richardson, Bruce <bruce.richardson@intel.com>
> > Subject: [PATCH 0/2] Various fixes for contigmem
> > 
> > Tiwei Bie (2):
> >   contigmem: free the allocated memory when error occurs
> >   contigmem: don't zero the pages during each mmap
> > 
> >  lib/librte_eal/bsdapp/contigmem/contigmem.c | 186
> > ++++++++++++++++++++++++----
> >  1 file changed, 161 insertions(+), 25 deletions(-)
> > 
> These look better solutions than the previous ones for multi-process.
> 
> Acked-by: Bruce Richardson <bruce.richardson@intel.com>
> 
> Given that this is not a new bug in this release, I don't think we should take the risk of applying the patches this late in the 17.05 release cycle. I therefore suggest that they be merged for 17.08 and once tested in that release, backported to 17.05 stable.
> 

Yeah, I agree. It's not a minor change.

Best regards,
Tiwei Bie

[PATCH v2 0/2] Various fixes for contigmem

[Tiwei Bie]

Sorry, I just noticed that I forgot to destroy the initialized mtx
before failing or unloading. V2 is to fix this issue.

---

v2: destroy the initialized mtx before failing or unloading

Tiwei Bie (2):
  contigmem: free the allocated memory when error occurs
  contigmem: don't zero the pages during each mmap

 lib/librte_eal/bsdapp/contigmem/contigmem.c | 194 ++++++++++++++++++++++++----
 1 file changed, 168 insertions(+), 26 deletions(-)

-- 
2.12.1

[PATCH v2 1/2] contigmem: free the allocated memory when error occurs

[Tiwei Bie]

Fixes: 764bf26873b9 ("add FreeBSD support")
Cc: stable@dpdk.org

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
---
 lib/librte_eal/bsdapp/contigmem/contigmem.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eal/bsdapp/contigmem/contigmem.c b/lib/librte_eal/bsdapp/contigmem/contigmem.c
index da971debe..03e3e8def 100644
--- a/lib/librte_eal/bsdapp/contigmem/contigmem.c
+++ b/lib/librte_eal/bsdapp/contigmem/contigmem.c
@@ -123,19 +123,21 @@ static int
 contigmem_load()
 {
 	char index_string[8], description[32];
-	int  i;
+	int  i, error = 0;
 
 	if (contigmem_num_buffers > RTE_CONTIGMEM_MAX_NUM_BUFS) {
 		printf("%d buffers requested is greater than %d allowed\n",
 				contigmem_num_buffers, RTE_CONTIGMEM_MAX_NUM_BUFS);
-		return EINVAL;
+		error = EINVAL;
+		goto error;
 	}
 
 	if (contigmem_buffer_size < PAGE_SIZE ||
 			(contigmem_buffer_size & (contigmem_buffer_size - 1)) != 0) {
 		printf("buffer size 0x%lx is not greater than PAGE_SIZE and "
 				"power of two\n", contigmem_buffer_size);
-		return EINVAL;
+		error = EINVAL;
+		goto error;
 	}
 
 	for (i = 0; i < contigmem_num_buffers; i++) {
@@ -145,7 +147,8 @@ contigmem_load()
 
 		if (contigmem_buffers[i] == NULL) {
 			printf("contigmalloc failed for buffer %d\n", i);
-			return ENOMEM;
+			error = ENOMEM;
+			goto error;
 		}
 
 		printf("%2u: virt=%p phys=%p\n", i, contigmem_buffers[i],
@@ -165,6 +168,14 @@ contigmem_load()
 			GID_WHEEL, 0600, "contigmem");
 
 	return 0;
+
+error:
+	for (i = 0; i < contigmem_num_buffers; i++)
+		if (contigmem_buffers[i] != NULL)
+			contigfree(contigmem_buffers[i], contigmem_buffer_size,
+					M_CONTIGMEM);
+
+	return error;
 }
 
 static int
-- 
2.12.1

[PATCH v2 2/2] contigmem: don't zero the pages during each mmap

[Tiwei Bie]

Don't zero the pages during each mmap. Instead, only zero the pages
when they are not already mmapped. Otherwise, the multi-process
support will be broken, as the pages will be zeroed when secondary
processes map the memory. Besides, track the open and mmap operations
on the cdev, and prevent the module from being unloaded when it is
still in use.

Fixes: 82f931805506 ("contigmem: zero all pages during mmap")
Cc: stable@dpdk.org

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
---
 lib/librte_eal/bsdapp/contigmem/contigmem.c | 183 ++++++++++++++++++++++++----
 1 file changed, 157 insertions(+), 26 deletions(-)

diff --git a/lib/librte_eal/bsdapp/contigmem/contigmem.c b/lib/librte_eal/bsdapp/contigmem/contigmem.c
index 03e3e8def..b201d7bf4 100644
--- a/lib/librte_eal/bsdapp/contigmem/contigmem.c
+++ b/lib/librte_eal/bsdapp/contigmem/contigmem.c
@@ -50,24 +50,37 @@ __FBSDID("$FreeBSD$");
 
 #include <vm/vm.h>
 #include <vm/pmap.h>
+#include <vm/vm_param.h>
 #include <vm/vm_object.h>
 #include <vm/vm_page.h>
 #include <vm/vm_pager.h>
+#include <vm/vm_phys.h>
+
+struct contigmem_buffer {
+	void           *addr;
+	int             refcnt;
+	struct mtx      mtx;
+};
+
+struct contigmem_vm_handle {
+	int             buffer_index;
+};
 
 static int              contigmem_load(void);
 static int              contigmem_unload(void);
 static int              contigmem_physaddr(SYSCTL_HANDLER_ARGS);
 
-static d_mmap_t         contigmem_mmap;
 static d_mmap_single_t  contigmem_mmap_single;
 static d_open_t         contigmem_open;
+static d_close_t        contigmem_close;
 
 static int              contigmem_num_buffers = RTE_CONTIGMEM_DEFAULT_NUM_BUFS;
 static int64_t          contigmem_buffer_size = RTE_CONTIGMEM_DEFAULT_BUF_SIZE;
 
 static eventhandler_tag contigmem_eh_tag;
-static void            *contigmem_buffers[RTE_CONTIGMEM_MAX_NUM_BUFS];
+static struct contigmem_buffer contigmem_buffers[RTE_CONTIGMEM_MAX_NUM_BUFS];
 static struct cdev     *contigmem_cdev = NULL;
+static int              contigmem_refcnt;
 
 TUNABLE_INT("hw.contigmem.num_buffers", &contigmem_num_buffers);
 TUNABLE_QUAD("hw.contigmem.buffer_size", &contigmem_buffer_size);
@@ -78,6 +91,8 @@ SYSCTL_INT(_hw_contigmem, OID_AUTO, num_buffers, CTLFLAG_RD,
 	&contigmem_num_buffers, 0, "Number of contigmem buffers allocated");
 SYSCTL_QUAD(_hw_contigmem, OID_AUTO, buffer_size, CTLFLAG_RD,
 	&contigmem_buffer_size, 0, "Size of each contiguous buffer");
+SYSCTL_INT(_hw_contigmem, OID_AUTO, num_references, CTLFLAG_RD,
+	&contigmem_refcnt, 0, "Number of references to contigmem");
 
 static SYSCTL_NODE(_hw_contigmem, OID_AUTO, physaddr, CTLFLAG_RD, 0,
 	"physaddr");
@@ -114,9 +129,10 @@ MODULE_VERSION(contigmem, 1);
 static struct cdevsw contigmem_ops = {
 	.d_name         = "contigmem",
 	.d_version      = D_VERSION,
-	.d_mmap         = contigmem_mmap,
+	.d_flags        = D_TRACKCLOSE,
 	.d_mmap_single  = contigmem_mmap_single,
 	.d_open         = contigmem_open,
+	.d_close        = contigmem_close,
 };
 
 static int
@@ -124,6 +140,7 @@ contigmem_load()
 {
 	char index_string[8], description[32];
 	int  i, error = 0;
+	void *addr;
 
 	if (contigmem_num_buffers > RTE_CONTIGMEM_MAX_NUM_BUFS) {
 		printf("%d buffers requested is greater than %d allowed\n",
@@ -141,18 +158,20 @@ contigmem_load()
 	}
 
 	for (i = 0; i < contigmem_num_buffers; i++) {
-		contigmem_buffers[i] =
-				contigmalloc(contigmem_buffer_size, M_CONTIGMEM, M_ZERO, 0,
-			BUS_SPACE_MAXADDR, contigmem_buffer_size, 0);
-
-		if (contigmem_buffers[i] == NULL) {
+		addr = contigmalloc(contigmem_buffer_size, M_CONTIGMEM, M_ZERO,
+			0, BUS_SPACE_MAXADDR, contigmem_buffer_size, 0);
+		if (addr == NULL) {
 			printf("contigmalloc failed for buffer %d\n", i);
 			error = ENOMEM;
 			goto error;
 		}
 
-		printf("%2u: virt=%p phys=%p\n", i, contigmem_buffers[i],
-				(void *)pmap_kextract((vm_offset_t)contigmem_buffers[i]));
+		printf("%2u: virt=%p phys=%p\n", i, addr,
+			(void *)pmap_kextract((vm_offset_t)addr));
+
+		mtx_init(&contigmem_buffers[i].mtx, "contigmem", NULL, MTX_DEF);
+		contigmem_buffers[i].addr = addr;
+		contigmem_buffers[i].refcnt = 0;
 
 		snprintf(index_string, sizeof(index_string), "%d", i);
 		snprintf(description, sizeof(description),
@@ -170,10 +189,13 @@ contigmem_load()
 	return 0;
 
 error:
-	for (i = 0; i < contigmem_num_buffers; i++)
-		if (contigmem_buffers[i] != NULL)
-			contigfree(contigmem_buffers[i], contigmem_buffer_size,
-					M_CONTIGMEM);
+	for (i = 0; i < contigmem_num_buffers; i++) {
+		if (contigmem_buffers[i].addr != NULL)
+			contigfree(contigmem_buffers[i].addr,
+				contigmem_buffer_size, M_CONTIGMEM);
+		if (mtx_initialized(&contigmem_buffers[i].mtx))
+			mtx_destroy(&contigmem_buffers[i].mtx);
+	}
 
 	return error;
 }
@@ -183,16 +205,22 @@ contigmem_unload()
 {
 	int i;
 
+	if (contigmem_refcnt > 0)
+		return EBUSY;
+
 	if (contigmem_cdev != NULL)
 		destroy_dev(contigmem_cdev);
 
 	if (contigmem_eh_tag != NULL)
 		EVENTHANDLER_DEREGISTER(process_exit, contigmem_eh_tag);
 
-	for (i = 0; i < RTE_CONTIGMEM_MAX_NUM_BUFS; i++)
-		if (contigmem_buffers[i] != NULL)
-			contigfree(contigmem_buffers[i], contigmem_buffer_size,
-					M_CONTIGMEM);
+	for (i = 0; i < RTE_CONTIGMEM_MAX_NUM_BUFS; i++) {
+		if (contigmem_buffers[i].addr != NULL)
+			contigfree(contigmem_buffers[i].addr,
+				contigmem_buffer_size, M_CONTIGMEM);
+		if (mtx_initialized(&contigmem_buffers[i].mtx))
+			mtx_destroy(&contigmem_buffers[i].mtx);
+	}
 
 	return 0;
 }
@@ -203,7 +231,7 @@ contigmem_physaddr(SYSCTL_HANDLER_ARGS)
 	uint64_t	physaddr;
 	int		index = (int)(uintptr_t)arg1;
 
-	physaddr = (uint64_t)vtophys(contigmem_buffers[index]);
+	physaddr = (uint64_t)vtophys(contigmem_buffers[index].addr);
 	return sysctl_handle_64(oidp, &physaddr, 0, req);
 }
 
@@ -211,22 +239,118 @@ static int
 contigmem_open(struct cdev *cdev, int fflags, int devtype,
 		struct thread *td)
 {
+
+	atomic_add_int(&contigmem_refcnt, 1);
+
+	return 0;
+}
+
+static int
+contigmem_close(struct cdev *cdev, int fflags, int devtype,
+		struct thread *td)
+{
+
+	atomic_subtract_int(&contigmem_refcnt, 1);
+
 	return 0;
 }
 
 static int
-contigmem_mmap(struct cdev *cdev, vm_ooffset_t offset, vm_paddr_t *paddr,
-		int prot, vm_memattr_t *memattr)
+contigmem_cdev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
+		vm_ooffset_t foff, struct ucred *cred, u_short *color)
 {
+	struct contigmem_vm_handle *vmh = handle;
+	struct contigmem_buffer *buf;
+
+	buf = &contigmem_buffers[vmh->buffer_index];
+
+	atomic_add_int(&contigmem_refcnt, 1);
+
+	mtx_lock(&buf->mtx);
+	if (buf->refcnt == 0)
+		memset(buf->addr, 0, contigmem_buffer_size);
+	buf->refcnt++;
+	mtx_unlock(&buf->mtx);
 
-	*paddr = offset;
 	return 0;
 }
 
+static void
+contigmem_cdev_pager_dtor(void *handle)
+{
+	struct contigmem_vm_handle *vmh = handle;
+	struct contigmem_buffer *buf;
+
+	buf = &contigmem_buffers[vmh->buffer_index];
+
+	mtx_lock(&buf->mtx);
+	buf->refcnt--;
+	mtx_unlock(&buf->mtx);
+
+	free(vmh, M_CONTIGMEM);
+
+	atomic_subtract_int(&contigmem_refcnt, 1);
+}
+
+static int
+contigmem_cdev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
+		vm_page_t *mres)
+{
+	vm_paddr_t paddr;
+	vm_page_t m_paddr, page;
+	vm_memattr_t memattr, memattr1;
+
+	memattr = object->memattr;
+
+	VM_OBJECT_WUNLOCK(object);
+
+	paddr = offset;
+
+	m_paddr = vm_phys_paddr_to_vm_page(paddr);
+	if (m_paddr != NULL) {
+		memattr1 = pmap_page_get_memattr(m_paddr);
+		if (memattr1 != memattr)
+			memattr = memattr1;
+	}
+
+	if (((*mres)->flags & PG_FICTITIOUS) != 0) {
+		/*
+		 * If the passed in result page is a fake page, update it with
+		 * the new physical address.
+		 */
+		page = *mres;
+		VM_OBJECT_WLOCK(object);
+		vm_page_updatefake(page, paddr, memattr);
+	} else {
+		/*
+		 * Replace the passed in reqpage page with our own fake page and
+		 * free up the all of the original pages.
+		 */
+		page = vm_page_getfake(paddr, memattr);
+		VM_OBJECT_WLOCK(object);
+		vm_page_replace_checked(page, object, (*mres)->pindex, *mres);
+		vm_page_lock(*mres);
+		vm_page_free(*mres);
+		vm_page_unlock(*mres);
+		*mres = page;
+	}
+
+	page->valid = VM_PAGE_BITS_ALL;
+
+	return VM_PAGER_OK;
+}
+
+static struct cdev_pager_ops contigmem_cdev_pager_ops = {
+	.cdev_pg_ctor = contigmem_cdev_pager_ctor,
+	.cdev_pg_dtor = contigmem_cdev_pager_dtor,
+	.cdev_pg_fault = contigmem_cdev_pager_fault,
+};
+
 static int
 contigmem_mmap_single(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size,
 		struct vm_object **obj, int nprot)
 {
+	struct contigmem_vm_handle *vmh;
 	uint64_t buffer_index;
 
 	/*
@@ -238,10 +362,17 @@ contigmem_mmap_single(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size,
 	if (buffer_index >= contigmem_num_buffers)
 		return EINVAL;
 
-	memset(contigmem_buffers[buffer_index], 0, contigmem_buffer_size);
-	*offset = (vm_ooffset_t)vtophys(contigmem_buffers[buffer_index]);
-	*obj = vm_pager_allocate(OBJT_DEVICE, cdev, size, nprot, *offset,
-			curthread->td_ucred);
+	if (size > contigmem_buffer_size)
+		return EINVAL;
+
+	vmh = malloc(sizeof(*vmh), M_CONTIGMEM, M_NOWAIT | M_ZERO);
+	if (vmh == NULL)
+		return ENOMEM;
+	vmh->buffer_index = buffer_index;
+
+	*offset = (vm_ooffset_t)vtophys(contigmem_buffers[buffer_index].addr);
+	*obj = cdev_pager_allocate(vmh, OBJT_DEVICE, &contigmem_cdev_pager_ops,
+			size, nprot, *offset, curthread->td_ucred);
 
 	return 0;
 }
-- 
2.12.1

Re: [dpdk-stable] [PATCH v2 2/2] contigmem: don't zero the pages during each mmap

[Shahaf Shuler]

Nélio, related to the issue you saw with secondary process support?

--Shahaf
Monday, May 22, 2017 12:04 PM, Tiwei Bie:
> Don't zero the pages during each mmap. Instead, only zero the pages when
> they are not already mmapped. Otherwise, the multi-process support will be
> broken, as the pages will be zeroed when secondary processes map the
> memory. Besides, track the open and mmap operations on the cdev, and
> prevent the module from being unloaded when it is still in use.
> 
> Fixes: 82f931805506 ("contigmem: zero all pages during mmap")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> Acked-by: Bruce Richardson <bruce.richardson@intel.com>
> ---
>  lib/librte_eal/bsdapp/contigmem/contigmem.c | 183
> ++++++++++++++++++++++++----
>  1 file changed, 157 insertions(+), 26 deletions(-)
> 
> diff --git a/lib/librte_eal/bsdapp/contigmem/contigmem.c
> b/lib/librte_eal/bsdapp/contigmem/contigmem.c
> index 03e3e8def..b201d7bf4 100644
> --- a/lib/librte_eal/bsdapp/contigmem/contigmem.c
> +++ b/lib/librte_eal/bsdapp/contigmem/contigmem.c
> @@ -50,24 +50,37 @@ __FBSDID("$FreeBSD$");
> 
>  #include <vm/vm.h>
>  #include <vm/pmap.h>
> +#include <vm/vm_param.h>
>  #include <vm/vm_object.h>
>  #include <vm/vm_page.h>
>  #include <vm/vm_pager.h>
> +#include <vm/vm_phys.h>
> +
> +struct contigmem_buffer {
> +	void           *addr;
> +	int             refcnt;
> +	struct mtx      mtx;
> +};
> +
> +struct contigmem_vm_handle {
> +	int             buffer_index;
> +};
> 
>  static int              contigmem_load(void);
>  static int              contigmem_unload(void);
>  static int              contigmem_physaddr(SYSCTL_HANDLER_ARGS);
> 
> -static d_mmap_t         contigmem_mmap;
>  static d_mmap_single_t  contigmem_mmap_single;
>  static d_open_t         contigmem_open;
> +static d_close_t        contigmem_close;
> 
>  static int              contigmem_num_buffers =
> RTE_CONTIGMEM_DEFAULT_NUM_BUFS;
>  static int64_t          contigmem_buffer_size =
> RTE_CONTIGMEM_DEFAULT_BUF_SIZE;
> 
>  static eventhandler_tag contigmem_eh_tag;
> -static void
> *contigmem_buffers[RTE_CONTIGMEM_MAX_NUM_BUFS];
> +static struct contigmem_buffer
> +contigmem_buffers[RTE_CONTIGMEM_MAX_NUM_BUFS];
>  static struct cdev     *contigmem_cdev = NULL;
> +static int              contigmem_refcnt;
> 
>  TUNABLE_INT("hw.contigmem.num_buffers", &contigmem_num_buffers);
> TUNABLE_QUAD("hw.contigmem.buffer_size", &contigmem_buffer_size);
> @@ -78,6 +91,8 @@ SYSCTL_INT(_hw_contigmem, OID_AUTO,
> num_buffers, CTLFLAG_RD,
>  	&contigmem_num_buffers, 0, "Number of contigmem buffers
> allocated");  SYSCTL_QUAD(_hw_contigmem, OID_AUTO, buffer_size,
> CTLFLAG_RD,
>  	&contigmem_buffer_size, 0, "Size of each contiguous buffer");
> +SYSCTL_INT(_hw_contigmem, OID_AUTO, num_references, CTLFLAG_RD,
> +	&contigmem_refcnt, 0, "Number of references to contigmem");
> 
>  static SYSCTL_NODE(_hw_contigmem, OID_AUTO, physaddr, CTLFLAG_RD,
> 0,
>  	"physaddr");
> @@ -114,9 +129,10 @@ MODULE_VERSION(contigmem, 1);  static struct
> cdevsw contigmem_ops = {
>  	.d_name         = "contigmem",
>  	.d_version      = D_VERSION,
> -	.d_mmap         = contigmem_mmap,
> +	.d_flags        = D_TRACKCLOSE,
>  	.d_mmap_single  = contigmem_mmap_single,
>  	.d_open         = contigmem_open,
> +	.d_close        = contigmem_close,
>  };
> 
>  static int
> @@ -124,6 +140,7 @@ contigmem_load()
>  {
>  	char index_string[8], description[32];
>  	int  i, error = 0;
> +	void *addr;
> 
>  	if (contigmem_num_buffers >
> RTE_CONTIGMEM_MAX_NUM_BUFS) {
>  		printf("%d buffers requested is greater than %d allowed\n",
> @@ -141,18 +158,20 @@ contigmem_load()
>  	}
> 
>  	for (i = 0; i < contigmem_num_buffers; i++) {
> -		contigmem_buffers[i] =
> -				contigmalloc(contigmem_buffer_size,
> M_CONTIGMEM, M_ZERO, 0,
> -			BUS_SPACE_MAXADDR, contigmem_buffer_size, 0);
> -
> -		if (contigmem_buffers[i] == NULL) {
> +		addr = contigmalloc(contigmem_buffer_size,
> M_CONTIGMEM, M_ZERO,
> +			0, BUS_SPACE_MAXADDR, contigmem_buffer_size,
> 0);
> +		if (addr == NULL) {
>  			printf("contigmalloc failed for buffer %d\n", i);
>  			error = ENOMEM;
>  			goto error;
>  		}
> 
> -		printf("%2u: virt=%p phys=%p\n", i, contigmem_buffers[i],
> -				(void
> *)pmap_kextract((vm_offset_t)contigmem_buffers[i]));
> +		printf("%2u: virt=%p phys=%p\n", i, addr,
> +			(void *)pmap_kextract((vm_offset_t)addr));
> +
> +		mtx_init(&contigmem_buffers[i].mtx, "contigmem", NULL,
> MTX_DEF);
> +		contigmem_buffers[i].addr = addr;
> +		contigmem_buffers[i].refcnt = 0;
> 
>  		snprintf(index_string, sizeof(index_string), "%d", i);
>  		snprintf(description, sizeof(description), @@ -170,10 +189,13
> @@ contigmem_load()
>  	return 0;
> 
>  error:
> -	for (i = 0; i < contigmem_num_buffers; i++)
> -		if (contigmem_buffers[i] != NULL)
> -			contigfree(contigmem_buffers[i],
> contigmem_buffer_size,
> -					M_CONTIGMEM);
> +	for (i = 0; i < contigmem_num_buffers; i++) {
> +		if (contigmem_buffers[i].addr != NULL)
> +			contigfree(contigmem_buffers[i].addr,
> +				contigmem_buffer_size, M_CONTIGMEM);
> +		if (mtx_initialized(&contigmem_buffers[i].mtx))
> +			mtx_destroy(&contigmem_buffers[i].mtx);
> +	}
> 
>  	return error;
>  }
> @@ -183,16 +205,22 @@ contigmem_unload()  {
>  	int i;
> 
> +	if (contigmem_refcnt > 0)
> +		return EBUSY;
> +
>  	if (contigmem_cdev != NULL)
>  		destroy_dev(contigmem_cdev);
> 
>  	if (contigmem_eh_tag != NULL)
>  		EVENTHANDLER_DEREGISTER(process_exit,
> contigmem_eh_tag);
> 
> -	for (i = 0; i < RTE_CONTIGMEM_MAX_NUM_BUFS; i++)
> -		if (contigmem_buffers[i] != NULL)
> -			contigfree(contigmem_buffers[i],
> contigmem_buffer_size,
> -					M_CONTIGMEM);
> +	for (i = 0; i < RTE_CONTIGMEM_MAX_NUM_BUFS; i++) {
> +		if (contigmem_buffers[i].addr != NULL)
> +			contigfree(contigmem_buffers[i].addr,
> +				contigmem_buffer_size, M_CONTIGMEM);
> +		if (mtx_initialized(&contigmem_buffers[i].mtx))
> +			mtx_destroy(&contigmem_buffers[i].mtx);
> +	}
> 
>  	return 0;
>  }
> @@ -203,7 +231,7 @@ contigmem_physaddr(SYSCTL_HANDLER_ARGS)
>  	uint64_t	physaddr;
>  	int		index = (int)(uintptr_t)arg1;
> 
> -	physaddr = (uint64_t)vtophys(contigmem_buffers[index]);
> +	physaddr = (uint64_t)vtophys(contigmem_buffers[index].addr);
>  	return sysctl_handle_64(oidp, &physaddr, 0, req);  }
> 
> @@ -211,22 +239,118 @@ static int
>  contigmem_open(struct cdev *cdev, int fflags, int devtype,
>  		struct thread *td)
>  {
> +
> +	atomic_add_int(&contigmem_refcnt, 1);
> +
> +	return 0;
> +}
> +
> +static int
> +contigmem_close(struct cdev *cdev, int fflags, int devtype,
> +		struct thread *td)
> +{
> +
> +	atomic_subtract_int(&contigmem_refcnt, 1);
> +
>  	return 0;
>  }
> 
>  static int
> -contigmem_mmap(struct cdev *cdev, vm_ooffset_t offset, vm_paddr_t
> *paddr,
> -		int prot, vm_memattr_t *memattr)
> +contigmem_cdev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t
> prot,
> +		vm_ooffset_t foff, struct ucred *cred, u_short *color)
>  {
> +	struct contigmem_vm_handle *vmh = handle;
> +	struct contigmem_buffer *buf;
> +
> +	buf = &contigmem_buffers[vmh->buffer_index];
> +
> +	atomic_add_int(&contigmem_refcnt, 1);
> +
> +	mtx_lock(&buf->mtx);
> +	if (buf->refcnt == 0)
> +		memset(buf->addr, 0, contigmem_buffer_size);
> +	buf->refcnt++;
> +	mtx_unlock(&buf->mtx);
> 
> -	*paddr = offset;
>  	return 0;
>  }
> 
> +static void
> +contigmem_cdev_pager_dtor(void *handle) {
> +	struct contigmem_vm_handle *vmh = handle;
> +	struct contigmem_buffer *buf;
> +
> +	buf = &contigmem_buffers[vmh->buffer_index];
> +
> +	mtx_lock(&buf->mtx);
> +	buf->refcnt--;
> +	mtx_unlock(&buf->mtx);
> +
> +	free(vmh, M_CONTIGMEM);
> +
> +	atomic_subtract_int(&contigmem_refcnt, 1); }
> +
> +static int
> +contigmem_cdev_pager_fault(vm_object_t object, vm_ooffset_t offset,
> int prot,
> +		vm_page_t *mres)
> +{
> +	vm_paddr_t paddr;
> +	vm_page_t m_paddr, page;
> +	vm_memattr_t memattr, memattr1;
> +
> +	memattr = object->memattr;
> +
> +	VM_OBJECT_WUNLOCK(object);
> +
> +	paddr = offset;
> +
> +	m_paddr = vm_phys_paddr_to_vm_page(paddr);
> +	if (m_paddr != NULL) {
> +		memattr1 = pmap_page_get_memattr(m_paddr);
> +		if (memattr1 != memattr)
> +			memattr = memattr1;
> +	}
> +
> +	if (((*mres)->flags & PG_FICTITIOUS) != 0) {
> +		/*
> +		 * If the passed in result page is a fake page, update it with
> +		 * the new physical address.
> +		 */
> +		page = *mres;
> +		VM_OBJECT_WLOCK(object);
> +		vm_page_updatefake(page, paddr, memattr);
> +	} else {
> +		/*
> +		 * Replace the passed in reqpage page with our own fake
> page and
> +		 * free up the all of the original pages.
> +		 */
> +		page = vm_page_getfake(paddr, memattr);
> +		VM_OBJECT_WLOCK(object);
> +		vm_page_replace_checked(page, object, (*mres)->pindex,
> *mres);
> +		vm_page_lock(*mres);
> +		vm_page_free(*mres);
> +		vm_page_unlock(*mres);
> +		*mres = page;
> +	}
> +
> +	page->valid = VM_PAGE_BITS_ALL;
> +
> +	return VM_PAGER_OK;
> +}
> +
> +static struct cdev_pager_ops contigmem_cdev_pager_ops = {
> +	.cdev_pg_ctor = contigmem_cdev_pager_ctor,
> +	.cdev_pg_dtor = contigmem_cdev_pager_dtor,
> +	.cdev_pg_fault = contigmem_cdev_pager_fault, };
> +
>  static int
>  contigmem_mmap_single(struct cdev *cdev, vm_ooffset_t *offset,
> vm_size_t size,
>  		struct vm_object **obj, int nprot)
>  {
> +	struct contigmem_vm_handle *vmh;
>  	uint64_t buffer_index;
> 
>  	/*
> @@ -238,10 +362,17 @@ contigmem_mmap_single(struct cdev *cdev,
> vm_ooffset_t *offset, vm_size_t size,
>  	if (buffer_index >= contigmem_num_buffers)
>  		return EINVAL;
> 
> -	memset(contigmem_buffers[buffer_index], 0,
> contigmem_buffer_size);
> -	*offset =
> (vm_ooffset_t)vtophys(contigmem_buffers[buffer_index]);
> -	*obj = vm_pager_allocate(OBJT_DEVICE, cdev, size, nprot, *offset,
> -			curthread->td_ucred);
> +	if (size > contigmem_buffer_size)
> +		return EINVAL;
> +
> +	vmh = malloc(sizeof(*vmh), M_CONTIGMEM, M_NOWAIT |
> M_ZERO);
> +	if (vmh == NULL)
> +		return ENOMEM;
> +	vmh->buffer_index = buffer_index;
> +
> +	*offset =
> (vm_ooffset_t)vtophys(contigmem_buffers[buffer_index].addr);
> +	*obj = cdev_pager_allocate(vmh, OBJT_DEVICE,
> &contigmem_cdev_pager_ops,
> +			size, nprot, *offset, curthread->td_ucred);
> 
>  	return 0;
>  }
> --
> 2.12.1

[PATCH v3 0/2] Various fixes for contigmem

[Tiwei Bie]

The vm_page_replace_checked() was introduced in FreeBSD 11, so the
build is broken on FreeBSD 10. The fix is to use vm_page_replace()
directly and do the check in caller.

---

v2: destroy the initialized mtx before failing or unloading
v3: fix build on FreeBSD 10, refine comments

Tiwei Bie (2):
  contigmem: free the allocated memory when error occurs
  contigmem: don't zero the pages during each mmap

 lib/librte_eal/bsdapp/contigmem/contigmem.c | 197 ++++++++++++++++++++++++----
 1 file changed, 171 insertions(+), 26 deletions(-)

-- 
2.12.1

[PATCH v3 1/2] contigmem: free the allocated memory when error occurs

[Tiwei Bie]

Fixes: 764bf26873b9 ("add FreeBSD support")
Cc: stable@dpdk.org

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
---
 lib/librte_eal/bsdapp/contigmem/contigmem.c | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eal/bsdapp/contigmem/contigmem.c b/lib/librte_eal/bsdapp/contigmem/contigmem.c
index da971debe..03e3e8def 100644
--- a/lib/librte_eal/bsdapp/contigmem/contigmem.c
+++ b/lib/librte_eal/bsdapp/contigmem/contigmem.c
@@ -123,19 +123,21 @@ static int
 contigmem_load()
 {
 	char index_string[8], description[32];
-	int  i;
+	int  i, error = 0;
 
 	if (contigmem_num_buffers > RTE_CONTIGMEM_MAX_NUM_BUFS) {
 		printf("%d buffers requested is greater than %d allowed\n",
 				contigmem_num_buffers, RTE_CONTIGMEM_MAX_NUM_BUFS);
-		return EINVAL;
+		error = EINVAL;
+		goto error;
 	}
 
 	if (contigmem_buffer_size < PAGE_SIZE ||
 			(contigmem_buffer_size & (contigmem_buffer_size - 1)) != 0) {
 		printf("buffer size 0x%lx is not greater than PAGE_SIZE and "
 				"power of two\n", contigmem_buffer_size);
-		return EINVAL;
+		error = EINVAL;
+		goto error;
 	}
 
 	for (i = 0; i < contigmem_num_buffers; i++) {
@@ -145,7 +147,8 @@ contigmem_load()
 
 		if (contigmem_buffers[i] == NULL) {
 			printf("contigmalloc failed for buffer %d\n", i);
-			return ENOMEM;
+			error = ENOMEM;
+			goto error;
 		}
 
 		printf("%2u: virt=%p phys=%p\n", i, contigmem_buffers[i],
@@ -165,6 +168,14 @@ contigmem_load()
 			GID_WHEEL, 0600, "contigmem");
 
 	return 0;
+
+error:
+	for (i = 0; i < contigmem_num_buffers; i++)
+		if (contigmem_buffers[i] != NULL)
+			contigfree(contigmem_buffers[i], contigmem_buffer_size,
+					M_CONTIGMEM);
+
+	return error;
 }
 
 static int
-- 
2.13.0

[PATCH v3 2/2] contigmem: don't zero the pages during each mmap

[Tiwei Bie]

Don't zero the pages during each mmap. Instead, only zero the pages
when they are not already mmapped. Otherwise, the multi-process
support will be broken, as the pages will be zeroed when secondary
processes map the memory. Besides, track the open and mmap operations
on the cdev, and prevent the module from being unloaded when it is
still in use.

Fixes: 82f931805506 ("contigmem: zero all pages during mmap")
Cc: stable@dpdk.org

Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
---
 lib/librte_eal/bsdapp/contigmem/contigmem.c | 186 ++++++++++++++++++++++++----
 1 file changed, 160 insertions(+), 26 deletions(-)

diff --git a/lib/librte_eal/bsdapp/contigmem/contigmem.c b/lib/librte_eal/bsdapp/contigmem/contigmem.c
index 03e3e8def..e8fb9087d 100644
--- a/lib/librte_eal/bsdapp/contigmem/contigmem.c
+++ b/lib/librte_eal/bsdapp/contigmem/contigmem.c
@@ -50,24 +50,37 @@ __FBSDID("$FreeBSD$");
 
 #include <vm/vm.h>
 #include <vm/pmap.h>
+#include <vm/vm_param.h>
 #include <vm/vm_object.h>
 #include <vm/vm_page.h>
 #include <vm/vm_pager.h>
+#include <vm/vm_phys.h>
+
+struct contigmem_buffer {
+	void           *addr;
+	int             refcnt;
+	struct mtx      mtx;
+};
+
+struct contigmem_vm_handle {
+	int             buffer_index;
+};
 
 static int              contigmem_load(void);
 static int              contigmem_unload(void);
 static int              contigmem_physaddr(SYSCTL_HANDLER_ARGS);
 
-static d_mmap_t         contigmem_mmap;
 static d_mmap_single_t  contigmem_mmap_single;
 static d_open_t         contigmem_open;
+static d_close_t        contigmem_close;
 
 static int              contigmem_num_buffers = RTE_CONTIGMEM_DEFAULT_NUM_BUFS;
 static int64_t          contigmem_buffer_size = RTE_CONTIGMEM_DEFAULT_BUF_SIZE;
 
 static eventhandler_tag contigmem_eh_tag;
-static void            *contigmem_buffers[RTE_CONTIGMEM_MAX_NUM_BUFS];
+static struct contigmem_buffer contigmem_buffers[RTE_CONTIGMEM_MAX_NUM_BUFS];
 static struct cdev     *contigmem_cdev = NULL;
+static int              contigmem_refcnt;
 
 TUNABLE_INT("hw.contigmem.num_buffers", &contigmem_num_buffers);
 TUNABLE_QUAD("hw.contigmem.buffer_size", &contigmem_buffer_size);
@@ -78,6 +91,8 @@ SYSCTL_INT(_hw_contigmem, OID_AUTO, num_buffers, CTLFLAG_RD,
 	&contigmem_num_buffers, 0, "Number of contigmem buffers allocated");
 SYSCTL_QUAD(_hw_contigmem, OID_AUTO, buffer_size, CTLFLAG_RD,
 	&contigmem_buffer_size, 0, "Size of each contiguous buffer");
+SYSCTL_INT(_hw_contigmem, OID_AUTO, num_references, CTLFLAG_RD,
+	&contigmem_refcnt, 0, "Number of references to contigmem");
 
 static SYSCTL_NODE(_hw_contigmem, OID_AUTO, physaddr, CTLFLAG_RD, 0,
 	"physaddr");
@@ -114,9 +129,10 @@ MODULE_VERSION(contigmem, 1);
 static struct cdevsw contigmem_ops = {
 	.d_name         = "contigmem",
 	.d_version      = D_VERSION,
-	.d_mmap         = contigmem_mmap,
+	.d_flags        = D_TRACKCLOSE,
 	.d_mmap_single  = contigmem_mmap_single,
 	.d_open         = contigmem_open,
+	.d_close        = contigmem_close,
 };
 
 static int
@@ -124,6 +140,7 @@ contigmem_load()
 {
 	char index_string[8], description[32];
 	int  i, error = 0;
+	void *addr;
 
 	if (contigmem_num_buffers > RTE_CONTIGMEM_MAX_NUM_BUFS) {
 		printf("%d buffers requested is greater than %d allowed\n",
@@ -141,18 +158,20 @@ contigmem_load()
 	}
 
 	for (i = 0; i < contigmem_num_buffers; i++) {
-		contigmem_buffers[i] =
-				contigmalloc(contigmem_buffer_size, M_CONTIGMEM, M_ZERO, 0,
-			BUS_SPACE_MAXADDR, contigmem_buffer_size, 0);
-
-		if (contigmem_buffers[i] == NULL) {
+		addr = contigmalloc(contigmem_buffer_size, M_CONTIGMEM, M_ZERO,
+			0, BUS_SPACE_MAXADDR, contigmem_buffer_size, 0);
+		if (addr == NULL) {
 			printf("contigmalloc failed for buffer %d\n", i);
 			error = ENOMEM;
 			goto error;
 		}
 
-		printf("%2u: virt=%p phys=%p\n", i, contigmem_buffers[i],
-				(void *)pmap_kextract((vm_offset_t)contigmem_buffers[i]));
+		printf("%2u: virt=%p phys=%p\n", i, addr,
+			(void *)pmap_kextract((vm_offset_t)addr));
+
+		mtx_init(&contigmem_buffers[i].mtx, "contigmem", NULL, MTX_DEF);
+		contigmem_buffers[i].addr = addr;
+		contigmem_buffers[i].refcnt = 0;
 
 		snprintf(index_string, sizeof(index_string), "%d", i);
 		snprintf(description, sizeof(description),
@@ -170,10 +189,13 @@ contigmem_load()
 	return 0;
 
 error:
-	for (i = 0; i < contigmem_num_buffers; i++)
-		if (contigmem_buffers[i] != NULL)
-			contigfree(contigmem_buffers[i], contigmem_buffer_size,
-					M_CONTIGMEM);
+	for (i = 0; i < contigmem_num_buffers; i++) {
+		if (contigmem_buffers[i].addr != NULL)
+			contigfree(contigmem_buffers[i].addr,
+				contigmem_buffer_size, M_CONTIGMEM);
+		if (mtx_initialized(&contigmem_buffers[i].mtx))
+			mtx_destroy(&contigmem_buffers[i].mtx);
+	}
 
 	return error;
 }
@@ -183,16 +205,22 @@ contigmem_unload()
 {
 	int i;
 
+	if (contigmem_refcnt > 0)
+		return EBUSY;
+
 	if (contigmem_cdev != NULL)
 		destroy_dev(contigmem_cdev);
 
 	if (contigmem_eh_tag != NULL)
 		EVENTHANDLER_DEREGISTER(process_exit, contigmem_eh_tag);
 
-	for (i = 0; i < RTE_CONTIGMEM_MAX_NUM_BUFS; i++)
-		if (contigmem_buffers[i] != NULL)
-			contigfree(contigmem_buffers[i], contigmem_buffer_size,
-					M_CONTIGMEM);
+	for (i = 0; i < RTE_CONTIGMEM_MAX_NUM_BUFS; i++) {
+		if (contigmem_buffers[i].addr != NULL)
+			contigfree(contigmem_buffers[i].addr,
+				contigmem_buffer_size, M_CONTIGMEM);
+		if (mtx_initialized(&contigmem_buffers[i].mtx))
+			mtx_destroy(&contigmem_buffers[i].mtx);
+	}
 
 	return 0;
 }
@@ -203,7 +231,7 @@ contigmem_physaddr(SYSCTL_HANDLER_ARGS)
 	uint64_t	physaddr;
 	int		index = (int)(uintptr_t)arg1;
 
-	physaddr = (uint64_t)vtophys(contigmem_buffers[index]);
+	physaddr = (uint64_t)vtophys(contigmem_buffers[index].addr);
 	return sysctl_handle_64(oidp, &physaddr, 0, req);
 }
 
@@ -211,22 +239,121 @@ static int
 contigmem_open(struct cdev *cdev, int fflags, int devtype,
 		struct thread *td)
 {
+
+	atomic_add_int(&contigmem_refcnt, 1);
+
+	return 0;
+}
+
+static int
+contigmem_close(struct cdev *cdev, int fflags, int devtype,
+		struct thread *td)
+{
+
+	atomic_subtract_int(&contigmem_refcnt, 1);
+
 	return 0;
 }
 
 static int
-contigmem_mmap(struct cdev *cdev, vm_ooffset_t offset, vm_paddr_t *paddr,
-		int prot, vm_memattr_t *memattr)
+contigmem_cdev_pager_ctor(void *handle, vm_ooffset_t size, vm_prot_t prot,
+		vm_ooffset_t foff, struct ucred *cred, u_short *color)
 {
+	struct contigmem_vm_handle *vmh = handle;
+	struct contigmem_buffer *buf;
+
+	buf = &contigmem_buffers[vmh->buffer_index];
+
+	atomic_add_int(&contigmem_refcnt, 1);
+
+	mtx_lock(&buf->mtx);
+	if (buf->refcnt == 0)
+		memset(buf->addr, 0, contigmem_buffer_size);
+	buf->refcnt++;
+	mtx_unlock(&buf->mtx);
 
-	*paddr = offset;
 	return 0;
 }
 
+static void
+contigmem_cdev_pager_dtor(void *handle)
+{
+	struct contigmem_vm_handle *vmh = handle;
+	struct contigmem_buffer *buf;
+
+	buf = &contigmem_buffers[vmh->buffer_index];
+
+	mtx_lock(&buf->mtx);
+	buf->refcnt--;
+	mtx_unlock(&buf->mtx);
+
+	free(vmh, M_CONTIGMEM);
+
+	atomic_subtract_int(&contigmem_refcnt, 1);
+}
+
+static int
+contigmem_cdev_pager_fault(vm_object_t object, vm_ooffset_t offset, int prot,
+		vm_page_t *mres)
+{
+	vm_paddr_t paddr;
+	vm_page_t m_paddr, page;
+	vm_memattr_t memattr, memattr1;
+
+	memattr = object->memattr;
+
+	VM_OBJECT_WUNLOCK(object);
+
+	paddr = offset;
+
+	m_paddr = vm_phys_paddr_to_vm_page(paddr);
+	if (m_paddr != NULL) {
+		memattr1 = pmap_page_get_memattr(m_paddr);
+		if (memattr1 != memattr)
+			memattr = memattr1;
+	}
+
+	if (((*mres)->flags & PG_FICTITIOUS) != 0) {
+		/*
+		 * If the passed in result page is a fake page, update it with
+		 * the new physical address.
+		 */
+		page = *mres;
+		VM_OBJECT_WLOCK(object);
+		vm_page_updatefake(page, paddr, memattr);
+	} else {
+		vm_page_t mret;
+		/*
+		 * Replace the passed in reqpage page with our own fake page and
+		 * free up the original page.
+		 */
+		page = vm_page_getfake(paddr, memattr);
+		VM_OBJECT_WLOCK(object);
+		mret = vm_page_replace(page, object, (*mres)->pindex);
+		KASSERT(mret == *mres,
+		    ("invalid page replacement, old=%p, ret=%p", *mres, mret));
+		vm_page_lock(mret);
+		vm_page_free(mret);
+		vm_page_unlock(mret);
+		*mres = page;
+	}
+
+	page->valid = VM_PAGE_BITS_ALL;
+
+	return VM_PAGER_OK;
+}
+
+static struct cdev_pager_ops contigmem_cdev_pager_ops = {
+	.cdev_pg_ctor = contigmem_cdev_pager_ctor,
+	.cdev_pg_dtor = contigmem_cdev_pager_dtor,
+	.cdev_pg_fault = contigmem_cdev_pager_fault,
+};
+
 static int
 contigmem_mmap_single(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size,
 		struct vm_object **obj, int nprot)
 {
+	struct contigmem_vm_handle *vmh;
 	uint64_t buffer_index;
 
 	/*
@@ -238,10 +365,17 @@ contigmem_mmap_single(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size,
 	if (buffer_index >= contigmem_num_buffers)
 		return EINVAL;
 
-	memset(contigmem_buffers[buffer_index], 0, contigmem_buffer_size);
-	*offset = (vm_ooffset_t)vtophys(contigmem_buffers[buffer_index]);
-	*obj = vm_pager_allocate(OBJT_DEVICE, cdev, size, nprot, *offset,
-			curthread->td_ucred);
+	if (size > contigmem_buffer_size)
+		return EINVAL;
+
+	vmh = malloc(sizeof(*vmh), M_CONTIGMEM, M_NOWAIT | M_ZERO);
+	if (vmh == NULL)
+		return ENOMEM;
+	vmh->buffer_index = buffer_index;
+
+	*offset = (vm_ooffset_t)vtophys(contigmem_buffers[buffer_index].addr);
+	*obj = cdev_pager_allocate(vmh, OBJT_DEVICE, &contigmem_cdev_pager_ops,
+			size, nprot, *offset, curthread->td_ucred);
 
 	return 0;
 }
-- 
2.13.0

Re: [PATCH v3 0/2] Various fixes for contigmem

[Thomas Monjalon]

04/06/2017 07:53, Tiwei Bie:
> The vm_page_replace_checked() was introduced in FreeBSD 11, so the
> build is broken on FreeBSD 10. The fix is to use vm_page_replace()
> directly and do the check in caller.
> 
> ---
> 
> v2: destroy the initialized mtx before failing or unloading
> v3: fix build on FreeBSD 10, refine comments
> 
> Tiwei Bie (2):
>   contigmem: free the allocated memory when error occurs
>   contigmem: don't zero the pages during each mmap

Applied, thanks