Date: Mon, 21 Sep 2020 17:25:26 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 246886] [sendfile] Nginx + NFS or FUSE causes VM stall Message-ID: <bug-246886-227-00xO69xcjQ@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-246886-227@https.bugs.freebsd.org/bugzilla/> References: <bug-246886-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D246886 --- Comment #55 from Alan Somers <asomers@FreeBSD.org> --- (In reply to Gleb Smirnoff from comment #54) It's not likely that aio_read makes a difference, since he is seeing the warning about "use unsafe AIO requests". That warning means that aio_read would've returned EOPNOTSUPP without doing anything. UNLESS there's a bug = in aio(4) very high in the stack, before the safety check, that is leaking a resource. Background: "unsafe" AIO means operations where there is no guarantee that = the operation will ever complete, due to network unreliability (in your case), = or disk unreliability, if you're accessing a disk directly rather than a file system. I've never liked that seat belt, because it blocks so many of AIO's best use cases. You can disable it by setting vfs.aio.enable_unsafe=3D1 in /etc/sysctl.conf. I'm puzzled that disabling aio in NGinx makes a difference. Could you plea= se repeat that experiment? It shouldn't matter, if unsafe AIO is disabled and you're serving from NFS or FUSE. --=20 You are receiving this mail because: You are the assignee for the bug.=
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