On Sat, 03 Jul 2010 13:56:13 +0200 Jens Axboe <axboe@xxxxxxxxx> wrote: > On 03/07/10 01.05, Andrew Morton wrote: > > On Thu, 1 Jul 2010 11:57:37 GMT > > bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > > > >> https://bugzilla.kernel.org/show_bug.cgi?id=16321 > >> > >> Summary: os unresponsive during buffered I/O > >> Product: IO/Storage > >> Version: 2.5 > >> Kernel Version: 2.6.34 > >> Platform: All > >> OS/Version: Linux > >> Tree: Mainline > >> Status: NEW > >> Severity: normal > >> Priority: P1 > >> Component: Block Layer > >> AssignedTo: axboe@xxxxxxxxx > >> ReportedBy: rrs@xxxxxxxxxxxxxx > >> Regression: No > >> > >> > >> I have been running these tests on my laptop running the 2.6.34 Debian kernel. > >> When doing buffered I/O, the OS completely stalls to any interactivity. I > >> cannot switch console tabs in my Desktop Environment and the mouse pointer does > >> not move. > >> > >> Eventually, I/O completes and every thing resumes to normal. There is no OOM > >> seen during the I/O operation. > >> If doing direct I/O, interactivity does not get penalized. > >> > > > > 1... > > > > 2... > > > > 3... > > > > FUCK!!! > > > > We've been trying to fix this stuff for ten years. Apparently, without > > success. Do we suck, or what? > > We suck. This is assigned to the block layer, but it must be something > a lot more fundemental than this. Either the vm is shitting itself, or > something else is sucking up the juice completely. Or the CPU scheduler > is going to pieces, I dunno. The report says that he cannot even move the > mouse or switch console tabs, clearly we are not (only) dealing with > an issue at the IO side. > > What else is interesting is that only a few people seem to see this. > What is different about their setup or their hardware?! I cannot > reproduce reports like this, and if it happened for everybody for > a simple 4 process random write like this, then everything would > grind to a halt. > > I propose we fly Andrew out to investigate in person :-) Hey, I suck more than anyone! My laptop goes absolutely utterly mouse-wont-move comatose for tens of minutes when it fetchmails 100 emails and 100 spamassassins go berzerk. It could be either a CPU scheduler thing, or an IO thing, or an evil combination of both. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>