Messages in this thread | | | Date | Mon, 27 Apr 2015 11:50:47 +0200 | From | Daniel Wagner <> | Subject | Re: [PATCH] lib/sort: Add 64 bit swap function |
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Hi Rasmus,
On 04/27/2015 09:45 AM, Rasmus Villemoes wrote: > On Mon, Apr 27 2015, Daniel Wagner <daniel.wagner@bmw-carit.de> wrote: > >> static int cmp_32(const void *a, const void *b) >> { >> return (int) (*(u32 *)a - *(u32 *)b); >> } >> >> static int cmp_64(const void *a, const void *b) >> { >> return (int) (*(u64 *)a - *(u64 *)b); >> } >> > > Please [1] don't [2] do [3] this [4]. > > [1] acbbe6fbb240a927ee1f5994f04d31267d422215 kcmp: fix standard comparison bug > > [2] ef17af2a817db97d42dd2ec0a425231748e23dbc fs: nfsd: Fix signedness bug in compare_blob > > [3] ddbc22e27e672b6b180757ea1d7f8481dbb88128 fs/hfs/catalog.c: fix comparison bug in hfs_cat_keycmp > > [4] 72392ed0eb6fde96826cb9d66bd4f50a7ba61450 kernfs: Fix kernfs_name_compare > > (sorry for not actually looking at the patch - this just triggered one > of my pet peeves).
Thanks for the pointers. I see, even the simplest stuff is not that simple. I'll keep an eye open for this one :)
In this case though it is not so bad. You are looking at test code. I used that one to test the performance of the patch not the correctness since there is the boot-time regression test for the sorting.
The main part of this path is a new u64 swap function:
+static void u64_swap(void *a, void *b, int size) +{ + u64 t = *(u64 *)a; + *(u64 *)a = *(u64 *)b; + *(u64 *)b = t; +} +
cheers, daniel
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