> > The other deadlock, in throttle_vm_writeout() is still to be solved. > > Let's go back to the original changelog: > > Author: marcelo.tosatti <marcelo.tosatti> > Date: Tue Mar 8 17:25:19 2005 +0000 > > [PATCH] vm: pageout throttling > > With silly pageout testcases it is possible to place huge amounts of > memory > under I/O. With a large request queue (CFQ uses 8192 requests) it is > possible to place _all_ memory under I/O at the same time. > > This means that all memory is pinned and unreclaimable and the VM gets > upset and goes oom. > > The patch limits the amount of memory which is under pageout writeout to > be > a little more than the amount of memory at which balance_dirty_pages() > callers will synchronously throttle. > > This means that heavy pageout activity can starve heavy writeback activity > completely, but heavy writeback activity will not cause starvation of > pageout. Because we don't want a simple `dd' to be causing excessive > latencies in page reclaim. > > Signed-off-by: Andrew Morton <[EMAIL PROTECTED]> > Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]> > > (A good one! I wrote it ;)) > > > I believe that the combination of dirty-page-tracking and its calls to > balance_dirty_pages() mean that we can now never get more than dirty_ratio > of memory into the dirty-or-writeback condition. > > The vm scanner can convert dirty pages into clean, under-writeback pages, > but it cannot increase the total of dirty+writeback.
What about swapout? That can increase the number of writeback pages, without decreasing the number of dirty pages, no? Miklos - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
