From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Simmons Date: Mon, 30 Sep 2019 14:55:50 -0400 Subject: [lustre-devel] [PATCH 091/151] lustre: llite: avoid live-lock when concurrent mmap()s In-Reply-To: <1569869810-23848-1-git-send-email-jsimmons@infradead.org> References: <1569869810-23848-1-git-send-email-jsimmons@infradead.org> Message-ID: <1569869810-23848-92-git-send-email-jsimmons@infradead.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org From: Bruno Faccini Patch is an attempt to delay page-fault retry from Client side for inode with extents being mmap()'ed, to prevent live-lock situation to occur with other page's competitors. WC-bug-id: https://jira.whamcloud.com/browse/LU-10149 Lustre-commit: cd793b4067b6 ("LU-10149 llite: avoid live-lock when concurrent mmap()s") Signed-off-by: Bruno Faccini Reviewed-on: https://review.whamcloud.com/30465 Reviewed-by: Andreas Dilger Reviewed-by: Bobi Jam Reviewed-by: Jinshan Xiong Reviewed-by: Oleg Drokin Signed-off-by: James Simmons --- fs/lustre/llite/llite_mmap.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/fs/lustre/llite/llite_mmap.c b/fs/lustre/llite/llite_mmap.c index 59fb400..14080b6 100644 --- a/fs/lustre/llite/llite_mmap.c +++ b/fs/lustre/llite/llite_mmap.c @@ -38,6 +38,7 @@ #include #include #include +#include #include #include @@ -153,7 +154,7 @@ static int __ll_page_mkwrite(struct vm_area_struct *vma, struct page *vmpage, int result; u16 refcheck; sigset_t old, new; - struct inode *inode; + struct inode *inode = NULL; struct ll_inode_info *lli; env = cl_env_get(&refcheck); @@ -229,6 +230,17 @@ static int __ll_page_mkwrite(struct vm_area_struct *vma, struct page *vmpage, CDEBUG(D_MMAP, "%s mkwrite with %d\n", current->comm, result); LASSERT(ergo(result == 0, PageLocked(vmpage))); + /* if page has been unmapped, presumably due to lock reclaim for + * concurrent usage, add some delay before retrying to prevent + * entering live-lock situation with competitors + */ + if (result == -ENODATA && inode) { + CDEBUG(D_MMAP, + "delaying new page-fault for inode %p to prevent live-lock\n", + inode); + msleep(20); + } + return result; } -- 1.8.3.1