Messages in this thread Patch in this message |  | | Date | Tue, 18 Sep 2001 05:37:11 +0200 | From | Andrea Arcangeli <> | Subject | Re: Linux 2.4.10-pre11 |
| |
On Mon, Sep 17, 2001 at 10:08:22PM -0300, Marcelo Tosatti wrote: > > > On Mon, 17 Sep 2001, Marcelo Tosatti wrote: > > > > > > > On Mon, 17 Sep 2001, Linus Torvalds wrote: > > > > > > > > Ok, the big thing here is continued merging, this time with Andrea. > > > > > > I still don't like some of the VM changes, but integrating Andrea's VM > > > changes results in (a) better performance and (b) much cleaner inactive > > > page handling in particular. Besides, for the 2.4.x tree, the big priority > > > is stability, we can re-address my other concerns during 2.5.x. > > > > Andrea, > > > > Could you please make a resume of your VM changes ? > > > > Its hard to keep up with VM changes this way. > > Andrea, > > I've just read a bit of your new VM code and I have a few comments. > > You completly removed the "inactive freeable pages" logic: There is no
yes, it wasn't relly useful to keep this list lazily, you either keep it enforced with locking overhead or such information isn't valuable.
> more distiction between "freeable inactive" and "free" pages. All VM work > is based on "freepages.high" watermark. I don't like that: it seems to
hardly on freepages.high:
diff -urN vm-ref/mm/swap.c vm/mm/swap.c --- vm-ref/mm/swap.c Tue Sep 18 00:18:17 2001 +++ vm/mm/swap.c Tue Sep 18 00:18:35 2001 @@ -24,50 +24,13 @@ #include <asm/uaccess.h> /* for copy_to/from_user */ #include <asm/pgtable.h> -/* - * We identify three levels of free memory. We never let free mem - * fall below the freepages.min except for atomic allocations. We - * start background swapping if we fall below freepages.high free - * pages, and we begin intensive swapping below freepages.low. - * - * Actual initialization is done in mm/page_alloc.c - */ -freepages_t freepages = { - 0, /* freepages.min */ - 0, /* freepages.low */ - 0 /* freepages.high */ -}; -
> make page freeing more aggressive over time.
I don't see your point with "page freeing more aggressive over time".
> Also, if we have several try_to_free_pages() callers, for different > classzones, I'm right saying that a caller with a "smaller" classzone can > "hide" pages in its "active_local_lru" and/or "inactive_local_lru" (during > shrink_cache) from other processes trying to free pages from those higher > zones ?
I'm deeply impressed, you seem to have understood the rewrite greatly well, congrats, this "hiding" was infact my main concern I had on the memclass check during shrink_cache, but I don't think this will ever give us troubles. In such there are suprious swapouts with HIGHMEM we'll just need to waste some cpu by lefting those pages visible with a few changes in shrink_cache, but again I'm almost sure there won't be problems, we do multiple scans before failing so those pages will return visible before the other task has a chance to fail the allocation.
Andrea - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
|  |