Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932440AbbBYV7Q (ORCPT ); Wed, 25 Feb 2015 16:59:16 -0500 Received: from smtp2.provo.novell.com ([137.65.250.81]:55389 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752868AbbBYV65 (ORCPT ); Wed, 25 Feb 2015 16:58:57 -0500 From: Davidlohr Bueso To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, dave@stgolabs.net, arnd@arndb.de, rric@kernel.org, linuxppc-dev@lists.ozlabs.org, cbe-oss-dev@lists.ozlabs.org, oprofile-list@lists.sourceforge.net, Davidlohr Bueso Subject: [PATCH 3/3] powerpc/oprofile: reduce mmap_sem hold for exe_file Date: Wed, 25 Feb 2015 13:58:37 -0800 Message-Id: <1424901517-25069-4-git-send-email-dave@stgolabs.net> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1424901517-25069-1-git-send-email-dave@stgolabs.net> References: <1424901517-25069-1-git-send-email-dave@stgolabs.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2197 Lines: 67 In the future mm->exe_file will be done without mmap_sem serialization, thus isolate and reorganize the related code to make the transition easier. Good users will, make use of the more standard get_mm_exe_file(), requiring only holding the mmap_sem to read the value, and relying on reference counting to make sure that the exe file won't dissappear underneath us while getting the dcookie. Cc: Arnd Bergmann Cc: Robert Richter Cc: linuxppc-dev@lists.ozlabs.org Cc: cbe-oss-dev@lists.ozlabs.org Cc: oprofile-list@lists.sourceforge.net Signed-off-by: Davidlohr Bueso --- Completely untested. arch/powerpc/oprofile/cell/spu_task_sync.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/oprofile/cell/spu_task_sync.c b/arch/powerpc/oprofile/cell/spu_task_sync.c index 1c27831..ed7b097 100644 --- a/arch/powerpc/oprofile/cell/spu_task_sync.c +++ b/arch/powerpc/oprofile/cell/spu_task_sync.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -322,18 +323,20 @@ get_exec_dcookie_and_offset(struct spu *spu, unsigned int *offsetp, unsigned long app_cookie = 0; unsigned int my_offset = 0; struct vm_area_struct *vma; + struct file *exe_file; struct mm_struct *mm = spu->mm; if (!mm) goto out; - down_read(&mm->mmap_sem); - - if (mm->exe_file) { - app_cookie = fast_get_dcookie(&mm->exe_file->f_path); - pr_debug("got dcookie for %pD\n", mm->exe_file); + exe_file = get_mm_exe_file(mm); + if (exe_file) { + app_cookie = fast_get_dcookie(&exe_file->f_path); + pr_debug("got dcookie for %pD\n", exe_file); + fput(exe_file); } + down_read(&mm->mmap_sem); for (vma = mm->mmap; vma; vma = vma->vm_next) { if (vma->vm_start > spu_ref || vma->vm_end <= spu_ref) continue; -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/