-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 On 08/14/14 15:47, Alan Cox wrote: > On 08/14/2014 01:24, Xin Li wrote: >> On 8/13/14 10:35 PM, John-Mark Gurney wrote: >>> Xin LI wrote this message on Thu, Aug 14, 2014 at 05:13 +0000: >>>> Author: delphij Date: Thu Aug 14 05:13:24 2014 New Revision: >>>> 269963 URL: http://svnweb.freebsd.org/changeset/base/269963 >>>> >>>> Log: Re-instate UMA cached backend for 4K - 64K allocations. >>>> New consumers like geli(4) uses malloc(9) to allocate >>>> temporary buffers that gets free'ed shortly, causing frequent >>>> TLB shootdown as observed in hwpmc supported flame graph. >> >>> Can we do even larger, like 128k for phys io sized blocks? >> >> Sure (Actually I'm running with 128k and 256k buckets enabled on >> my own storage box; with r269964 we can easily add new buckets >> without actually activating them by default). >> >> However, I'm relented to add them right now because the current >> malloc(9) implementation would use the next bucket size, which is >> 2x of the previous one, when the requested size is only a little >> bit larger than the smaller chunk's size. In real world the >> larger bucket could eat more memory than all smaller but greater >> than page-sized bucket combined (the actual consumption is still >> small, though). >> > > The current code already supports sizes that are not powers of 2. > For example, with > > Index: kern/kern_malloc.c > =================================================================== > > - --- kern/kern_malloc.c (revision 269997) > +++ kern/kern_malloc.c (working copy) @@ -152,8 +152,11 @@ struct > { {2048, "2048", }, {4096, "4096", }, {8192, "8192", }, + > {12228, "12228", }, {16384, "16384", }, + {24576, "24576", > }, {32768, "32768", }, + {49152, "49152", }, {65536, "65536", > }, {0, NULL}, };
Unrelated to the functionality, but this would break 'vmstat -m' which assumes power of two allocations... Cheers, - -- Xin LI <delp...@delphij.net> https://www.delphij.net/ FreeBSD - The Power to Serve! Live free or die -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0 iQIcBAEBCgAGBQJT7jcwAAoJEJW2GBstM+nsGH8P/3ghcaRXNjy+w0bkkya0ixsX KpYvah9S2v7mfk8GtN+xSQaTRtVRqmcWCrRnDLgcmAtRQr0q73T2H5w7a8fVG3sN c3X3c4dyn5XDzrNGmrIe4hAfDNK1F0WPF5nkMpAHhh/EXV5cPynLP2hlZHT6wWa9 MO0ZVAqVjfe1ZIi71AmU69GLGqgTTykMWUo2BKfRZg1LoMektW5Ugj4KlUsvD+SF +FpU7wCSc19br3i27MTsUWU7RKyTyycSOrl/FpZtWMMtyB4RELxUa3QYQQsk2FuM YNWRcBtGaMisNqALMghmJT6l2dtmcPGS47AcyyQnR6w+VziWuYe6Lq/D3iz2EgCM QqFGxp/oDauSjBUfgB83CDfdjrp2x277szBIc9OmvgsyhVgAfDoZzdWuyW2azKi5 c7RN10sqwGhFCLYScgtM0Y2TS8wBGc/uJ7nQMdFUjZ7yNsW3xEU0vAHB0QKar5Tt nIXOiigpO3Ql71l0safPIBvkzWNDHviwuBgGnEgrel86T9tGStRmDCE5YtIaamJV R9Wlhaj7e++4+IC5AEUQvSE1yrg5v5GZVVZEsEBcy1MUlDo5+jqzoxU9lp1sDLAN z7S1PkjWmurFykKl8Vvgi5UHXv5e8u6wFEjf1VDoKw/cqvRWLS/9ifS3ou0EwrJl yBW1Vm9lx6QJohCfq+/q =NvIK -----END PGP SIGNATURE----- _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
