Messages in this thread | | | Date | Fri, 24 May 2002 00:51:59 -0700 | From | William Lee Irwin III <> | Subject | Re: inode highmem imbalance fix [Re: Bug with shared memory.] |
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On Fri, May 24, 2002 at 09:33:41AM +0200, Andrea Arcangeli wrote: > Here it is, you should apply it together with vm-35 that you need too > for the bh/highmem balance (or on top of 2.4.19pre8aa3). I tested it > slightly on uml and it didn't broke so far, so be careful because it's not > very well tested yet. On the lines of what Alexey suggested originally, > if goal isn't reached, in a second pass we shrink the cache too, but > only if the cache is the only reason for the "pinning" beahiour of the > inode. If for example there are dirty blocks of metadata or of data > belonging to the inode we wakeup_bdflush instead and we never shrink the > cache in such case. If the inode itself is dirty as well we let the two > passes fail so we will schedule the work for keventd. This logic should > ensure we never fall into shrinking the cache for no good reason and > that we free the cache only for the inodes that we actually go ahead and > free. (basically only dirty pages set with SetPageDirty aren't trapped > by the logic before calling the invalidate, like ramfs, but that's > expected of course, those pages cannot be damaged by the non destructive > invalidate anyways) > Comments?
I haven't had the chance to give this a test run yet, but it looks very promising. I have a slight concern about the hold time of the inode_lock because prune_icache() already generates some amount of contention, but what you've presented appears to be necessary to prevent lethal cache bloat, and so that concern is secondary at most. I'll give it a test run tomorrow if no one else on-site gets to it first, though with the proviso that I've not been involved in workloads triggering this specific KVA exhaustion issue, so what testing I can do is limited.
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