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Commit 57666519 authored by Alex Elder's avatar Alex Elder
Browse files

ceph: use a shared zero page rather than one per messenger 



Each messenger allocates a page to be used when writing zeroes
out in the event of error or other abnormal condition.  Instead,
use the kernel ZERO_PAGE() for that purpose.

Signed-off-by: default avatarAlex Elder <elder@dreamhost.com>
Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent 80834312

include/linux/ceph/messenger.h

+0 −1
Original line number Original line Diff line number Diff line
@@ -54,7 +54,6 @@ struct ceph_connection_operations { 
struct ceph_messenger {

struct ceph_messenger {

	struct ceph_entity_inst inst;    /* my name+address */

	struct ceph_entity_inst inst;    /* my name+address */

	struct ceph_entity_addr my_enc_addr;

	struct ceph_entity_addr my_enc_addr;

	struct page *zero_page;          /* used in certain error cases */





	bool nocrc;

	bool nocrc;

net/ceph/messenger.c

+29 −14
Original line number Original line Diff line number Diff line
@@ -52,6 +52,9 @@ static char addr_str[MAX_ADDR_STR][MAX_ADDR_STR_LEN]; 
static DEFINE_SPINLOCK(addr_str_lock);

static DEFINE_SPINLOCK(addr_str_lock);

static int last_addr_str;

static int last_addr_str;





static struct page *zero_page;		/* used in certain error cases */

static void *zero_page_address;		/* kernel virtual addr of zero_page */



const char *ceph_pr_addr(const struct sockaddr_storage *ss)

const char *ceph_pr_addr(const struct sockaddr_storage *ss)

{

{

	int i;

	int i;
@@ -99,18 +102,41 @@ struct workqueue_struct *ceph_msgr_wq; 




int ceph_msgr_init(void)

int ceph_msgr_init(void)

{

{

	BUG_ON(zero_page != NULL);

	zero_page = ZERO_PAGE(0);

	page_cache_get(zero_page);



	BUG_ON(zero_page_address != NULL);

	zero_page_address = kmap(zero_page);



	ceph_msgr_wq = alloc_workqueue("ceph-msgr", WQ_NON_REENTRANT, 0);

	ceph_msgr_wq = alloc_workqueue("ceph-msgr", WQ_NON_REENTRANT, 0);

	if (!ceph_msgr_wq) {

	if (!ceph_msgr_wq) {

		pr_err("msgr_init failed to create workqueue\n");

		pr_err("msgr_init failed to create workqueue\n");



		zero_page_address = NULL;

		kunmap(zero_page);

		page_cache_release(zero_page);

		zero_page = NULL;



		return -ENOMEM;

		return -ENOMEM;

	}

	}



	return 0;

	return 0;

}

}

EXPORT_SYMBOL(ceph_msgr_init);

EXPORT_SYMBOL(ceph_msgr_init);





void ceph_msgr_exit(void)

void ceph_msgr_exit(void)

{

{

	BUG_ON(ceph_msgr_wq == NULL);

	destroy_workqueue(ceph_msgr_wq);

	destroy_workqueue(ceph_msgr_wq);



	BUG_ON(zero_page_address == NULL);

	zero_page_address = NULL;



	BUG_ON(zero_page == NULL);

	kunmap(zero_page);

	page_cache_release(zero_page);

	zero_page = NULL;

}

}

EXPORT_SYMBOL(ceph_msgr_exit);

EXPORT_SYMBOL(ceph_msgr_exit);
@@ -841,9 +867,9 @@ static int write_partial_msg_pages(struct ceph_connection *con) 
			max_write = bv->bv_len;

			max_write = bv->bv_len;

#endif

#endif

		} else {

		} else {

			page = con->msgr->zero_page;

			page = zero_page;

			if (crc)

			if (crc)

				kaddr = page_address(con->msgr->zero_page);

				kaddr = zero_page_address;

		}

		}

		len = min_t(int, max_write - con->out_msg_pos.page_pos,

		len = min_t(int, max_write - con->out_msg_pos.page_pos,

			    total_max_write);

			    total_max_write);
@@ -914,7 +940,7 @@ static int write_partial_skip(struct ceph_connection *con) 




	while (con->out_skip > 0) {

	while (con->out_skip > 0) {

		struct kvec iov = {

		struct kvec iov = {

			.iov_base = page_address(con->msgr->zero_page),

			.iov_base = zero_page_address,

			.iov_len = min(con->out_skip, (int)PAGE_CACHE_SIZE)

			.iov_len = min(con->out_skip, (int)PAGE_CACHE_SIZE)

		};

		};
@@ -2222,15 +2248,6 @@ struct ceph_messenger *ceph_messenger_create(struct ceph_entity_addr *myaddr, 




	spin_lock_init(&msgr->global_seq_lock);

	spin_lock_init(&msgr->global_seq_lock);





	/* the zero page is needed if a request is "canceled" while the message

	 * is being written over the socket */

	msgr->zero_page = __page_cache_alloc(GFP_KERNEL | __GFP_ZERO);

	if (!msgr->zero_page) {

		kfree(msgr);

		return ERR_PTR(-ENOMEM);

	}

	kmap(msgr->zero_page);



	if (myaddr)

	if (myaddr)

		msgr->inst.addr = *myaddr;

		msgr->inst.addr = *myaddr;
@@ -2247,8 +2264,6 @@ EXPORT_SYMBOL(ceph_messenger_create); 
void ceph_messenger_destroy(struct ceph_messenger *msgr)

void ceph_messenger_destroy(struct ceph_messenger *msgr)

{

{

	dout("destroy %p\n", msgr);

	dout("destroy %p\n", msgr);

	kunmap(msgr->zero_page);

	__free_page(msgr->zero_page);

	kfree(msgr);

	kfree(msgr);

	dout("destroyed messenger %p\n", msgr);

	dout("destroyed messenger %p\n", msgr);

}

}