On Tue, 30 May 2006, Vivek Dharmadhikari wrote: > Hello Alan > > > When you mount the USB drive, do you use the "-o sync" option? That could > > cause the delays and the errors that you see. They are not caused by > > problems in the 2.6.12 USB drivers. (Well, some of the delays are caused > > by the driver -- but they wouldn't be there if no errors occurred. > > No, i do not use any options when i mount the usb drive. I assume that > the mount command do not use sync option by default.
Check /proc/mounts and make sure. That's the only reason I can think of why your writes are transferring only one sector at a time. It would help if you upgraded to a more recent kernel version. The device reset code in usb-storage has changed a lot since 2.6.12. > I am still facing USB hang issue and i did some debuggging and my > obeservations are given below. > > 1.A file copy to USB hard disk results in drop in free memory. The free > memory is consumed by kernel page cache and is not released. Note that > my reference board has ONLY 32MB of SDRAM and free memory drops below > 1Mb when USB file copy is in progress. This wouldn't happen, or wouldn't be as bad, if your transfer sizes were larger. > 2.During the copy operation, the pdflush daemon gets triggerd(as seen by > top) indicating the system is low on memory. Any attempts to do anothter > copy to USB fails as kernel kills cp process due to OOM. These aren't USB questions, but I'll do my best to answer them. > Is there any way to instruct the kernel NOT to use page cache ? No. > Any idea about why the page cache memory is not released ? No. > what commands > can be used to flush the page cache ? sync. Alan Stern ------------------------------------------------------- All the advantages of Linux Managed Hosting--Without the Cost and Risk! Fully trained technicians. The highest number of Red Hat certifications in the hosting industry. Fanatical Support. Click to learn more http://sel.as-us.falkag.net/sel?cmd=lnk&kid=107521&bid=248729&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
