From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kyle Fortin Subject: [PATCH] libiscsi: use vzalloc for large allocations in iscsi_pool_init Date: Mon, 3 Apr 2017 06:30:21 -0700 Message-ID: <1491226221-24621-1-git-send-email-kyle.fortin@oracle.com> Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:48199 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753004AbdDCNab (ORCPT ); Mon, 3 Apr 2017 09:30:31 -0400 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: lduncan@suse.com, cleech@redhat.com, jejb@linux.vnet.ibm.com, martin.petersen@oracle.com, open-iscsi@googlegroups.com, linux-scsi@vger.kernel.org Cc: Kyle Fortin iscsiadm session login can fail with the following error: iscsiadm: Could not login to [iface: default, target: iqn.1986-03.com... iscsiadm: initiator reported error (9 - internal error) When /etc/iscsi/iscsid.conf sets node.session.cmds_max = 4096, it results in 64K-sized kmallocs per session. A system under fragmented slab pressure may not have any 64K objects available and fail iscsiadm session login. Even though memory objects of a smaller size are available, the large order allocation ends up failing. The kernel will print a warning and dump_stack, like below: iscsid: page allocation failure: order:4, mode:0xc0d0 CPU: 0 PID: 2456 Comm: iscsid Not tainted 4.1.12-61.1.28.el6uek.x86_64 #2 Call Trace: [] dump_stack+0x63/0x83 [] warn_alloc_failed+0xea/0x140 [] __alloc_pages_slowpath+0x409/0x760 [] __alloc_pages_nodemask+0x2b1/0x2d0 [] ? dev_attr_host_ipaddress+0x20/0xffffffffffffc722 [] alloc_pages_current+0xaf/0x170 [] alloc_kmem_pages+0x31/0xd0 [] ? iscsi_transport_group+0x20/0xffffffffffffc7e2 [] kmalloc_order+0x18/0x50 [] kmalloc_order_trace+0x34/0xe0 [] ? transport_remove_classdev+0x70/0x70 [] __kmalloc+0x27d/0x2a0 [] ? complete_all+0x4d/0x60 [] iscsi_pool_init+0x69/0x160 [libiscsi] [] ? device_initialize+0xb0/0xd0 [] iscsi_session_setup+0x180/0x2f4 [libiscsi] [] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp] [] iscsi_sw_tcp_session_create+0xcf/0x150 [iscsi_tcp] [] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp] [] iscsi_if_create_session+0x33/0xd0 [] ? iscsi_max_lun+0x20/0xfffffffffffffa9e [iscsi_tcp] [] iscsi_if_recv_msg+0x508/0x8c0 [scsi_transport_iscsi] [] ? __alloc_pages_nodemask+0x19b/0x2d0 [] ? __kmalloc_node_track_caller+0x209/0x2c0 [] iscsi_if_rx+0x7c/0x200 [scsi_transport_iscsi] [] netlink_unicast+0x126/0x1c0 [] netlink_sendmsg+0x36c/0x400 [] sock_sendmsg+0x4d/0x60 [] ___sys_sendmsg+0x30a/0x330 [] ? handle_pte_fault+0x20c/0x230 [] ? __handle_mm_fault+0x1bc/0x330 [] ? handle_mm_fault+0xb2/0x1a0 [] __sys_sendmsg+0x49/0x90 [] SyS_sendmsg+0x19/0x20 [] system_call_fastpath+0x12/0x71 Use vzalloc for iscsi_pool allocations larger than PAGE_SIZE. This only affects hosts using a non-standard larger /etc/iscsi/iscsid.conf node.session.cmds_max value. Since iscsi_pool_init is also called to allocate very small pools per cmd for r2t handling, it is best to retain using kzalloc for those allocations. Signed-off-by: Kyle Fortin Tested-by: Kyle Fortin Reviewed-by: Joseph Slember Reviewed-by: Lance Hartmann --- drivers/scsi/libiscsi.c | 15 +++++++++++++-- include/scsi/libiscsi.h | 1 + 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c index 3fca34a675af..5a622ba2f10d 100644 --- a/drivers/scsi/libiscsi.c +++ b/drivers/scsi/libiscsi.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include #include @@ -2546,6 +2547,7 @@ int iscsi_eh_recover_target(struct scsi_cmnd *sc) iscsi_pool_init(struct iscsi_pool *q, int max, void ***items, int item_size) { int i, num_arrays = 1; + int alloc_size; memset(q, 0, sizeof(*q)); @@ -2555,7 +2557,13 @@ int iscsi_eh_recover_target(struct scsi_cmnd *sc) * the array. */ if (items) num_arrays++; - q->pool = kzalloc(num_arrays * max * sizeof(void*), GFP_KERNEL); + + alloc_size = num_arrays * max * sizeof(void *); + if (alloc_size > PAGE_SIZE) { + q->pool = vzalloc(alloc_size); + q->is_pool_vmalloc = true; + } else + q->pool = kzalloc(alloc_size, GFP_KERNEL); if (q->pool == NULL) return -ENOMEM; @@ -2589,7 +2597,10 @@ void iscsi_pool_free(struct iscsi_pool *q) for (i = 0; i < q->max; i++) kfree(q->pool[i]); - kfree(q->pool); + if (q->is_pool_vmalloc) + vfree(q->pool); + else + kfree(q->pool); } EXPORT_SYMBOL_GPL(iscsi_pool_free); diff --git a/include/scsi/libiscsi.h b/include/scsi/libiscsi.h index 583875ea136a..e3421e527559 100644 --- a/include/scsi/libiscsi.h +++ b/include/scsi/libiscsi.h @@ -258,6 +258,7 @@ struct iscsi_pool { struct kfifo queue; /* FIFO Queue */ void **pool; /* Pool of elements */ int max; /* Max number of elements */ + bool is_pool_vmalloc; }; /* Session's states */ -- 1.8.3.1