From 5766651971e81298732466c9aa462ff47898ba37 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Mon, 23 Jan 2012 15:49:27 -0600 Subject: [PATCH] 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: Alex Elder Signed-off-by: Sage Weil --- include/linux/ceph/messenger.h | 1 - net/ceph/messenger.c | 43 +++++++++++++++++++++++----------- 2 files changed, 29 insertions(+), 15 deletions(-) diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h index ffbeb2c217b4..6b5af5f976d1 100644 --- a/include/linux/ceph/messenger.h +++ b/include/linux/ceph/messenger.h @@ -54,7 +54,6 @@ struct ceph_connection_operations { struct ceph_messenger { struct ceph_entity_inst inst; /* my name+address */ struct ceph_entity_addr my_enc_addr; - struct page *zero_page; /* used in certain error cases */ bool nocrc; diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index d11f91b05452..738356255e0b 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -52,6 +52,9 @@ static char addr_str[MAX_ADDR_STR][MAX_ADDR_STR_LEN]; static DEFINE_SPINLOCK(addr_str_lock); 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) { int i; @@ -99,18 +102,41 @@ struct workqueue_struct *ceph_msgr_wq; 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); if (!ceph_msgr_wq) { 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 0; } EXPORT_SYMBOL(ceph_msgr_init); void ceph_msgr_exit(void) { + BUG_ON(ceph_msgr_wq == NULL); 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); @@ -841,9 +867,9 @@ static int write_partial_msg_pages(struct ceph_connection *con) max_write = bv->bv_len; #endif } else { - page = con->msgr->zero_page; + page = zero_page; 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, total_max_write); @@ -914,7 +940,7 @@ static int write_partial_skip(struct ceph_connection *con) while (con->out_skip > 0) { 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) }; @@ -2222,15 +2248,6 @@ struct ceph_messenger *ceph_messenger_create(struct ceph_entity_addr *myaddr, 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) msgr->inst.addr = *myaddr; @@ -2247,8 +2264,6 @@ EXPORT_SYMBOL(ceph_messenger_create); void ceph_messenger_destroy(struct ceph_messenger *msgr) { dout("destroy %p\n", msgr); - kunmap(msgr->zero_page); - __free_page(msgr->zero_page); kfree(msgr); dout("destroyed messenger %p\n", msgr); }