Messages in this thread | | | Subject | Re: [PATCH -mm -v2] mm, swap: Sort swap entries before free | From | Rik van Riel <> | Date | Wed, 05 Apr 2017 10:40:31 -0400 |
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On Wed, 2017-04-05 at 15:10 +0800, Huang, Ying wrote: > To solve the issue, the per-CPU buffer is sorted according to the > swap > device before freeing the swap entries. Test shows that the time > spent by swapcache_free_entries() could be reduced after the patch.
That makes a lot of sense.
> @@ -1075,6 +1083,8 @@ void swapcache_free_entries(swp_entry_t > *entries, int n) > > prev = NULL; > p = NULL; > + if (nr_swapfiles > 1) > + sort(entries, n, sizeof(entries[0]), swp_entry_cmp, > NULL);
But it really wants a comment in the code, so people reading the code a few years from now can see why we are sorting things we are about to free.
Maybe something like: /* Sort swap entries by swap device, so each lock is only taken once. */
> for (i = 0; i < n; ++i) { > p = swap_info_get_cont(entries[i], prev); > if (p) -- All rights reversed [unhandled content-type:application/pgp-signature] | |