On Thu, 22 Mar 2012 10:24:22 -0600 Jason Mattax <jmattax@xxxxxxxxxxxxxxx> wrote: > Swapon very slow with swapfiles. > > After upgrading the kernel my swap file loads very slowly, while a swap > partition is unaffected. With the newer kernel (2.6.33.1) I get > > # time swapon -v /var/swapfile > swapon on /var/swapfile > swapon: /var/swapfile: found swap signature: version 1, page-size 4, > same byte order > swapon: /var/swapfile: pagesize=4096, swapsize=6442450944, > devsize=6442450944 > > real 4m35.355s > user 0m0.001s > sys 0m1.786s > > while with the older kernel (2.6.32.27) I get > # time swapon -v /var/swapfile > swapon on /var/swapfile > swapon: /var/swapfile: found swap signature: version 1, page-size 4, > same byte order > swapon: /var/swapfile: pagesize=4096, swapsize=6442450944, > devsize=6442450944 > > real 0m1.158s > user 0m0.000s > sys 0m0.876s > > this stays true even for new swapfiles I create with dd. > > the file is on an OCZ Vertex2 SSD. Probably the vertex2 discard problem. We just merged a patch which will hopefully fix it: --- a/mm/swapfile.c~swap-dont-do-discard-if-no-discard-option-added +++ a/mm/swapfile.c @@ -2103,7 +2103,7 @@ SYSCALL_DEFINE2(swapon, const char __use p->flags |= SWP_SOLIDSTATE; p->cluster_next = 1 + (random32() % p->highest_bit); } - if (discard_swap(p) == 0 && (swap_flags & SWAP_FLAG_DISCARD)) + if ((swap_flags & SWAP_FLAG_DISCARD) && discard_swap(p) == 0) p->flags |= SWP_DISCARDABLE; } But Hugh doesn't like it and won't tell us why :) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>