On 08/09/2015 14:29, Jay Rolette wrote: > Most of the code in sort_by_physaddr() should be replaced by a call to > qsort() instead. Less code and gets rid of an O(n^2) sort. It's only > init code, but given how long EAL init takes, every bit helps. > Fair enough. Actually, we already use qsort in lib/librte_eal/linuxapp/eal/eal_hugeapge_info.c
> I submitted a patch for this close to a year ago: > http://dpdk.org/dev/patchwork/patch/2061/ > I just had a quick look at it and seems to be archived with 'Changes Requested' status. I will comment on it. Sergio > Jay > > On Tue, Sep 8, 2015 at 7:45 AM, Gonzalez Monroy, Sergio > <sergio.gonzalez.monroy at intel.com > <mailto:sergio.gonzalez.monroy at intel.com>> wrote: > > Hi Ralf, > > Just a few comments/suggestions: > > Add 'eal/linux:' to the commit title, ie: > "eal/linux: change hugepage sorting to avoid overlapping memcpy" > > On 04/09/2015 11:14, Ralf Hoffmann wrote: > > with only one hugepage or already sorted hugepage addresses, > the sort > function called memcpy with same src and dst pointer. > Debugging with > valgrind will issue a warning about overlapping area. This > patch changes > the bubble sort to avoid this behavior. Also, the function > cannot fail > any longer. > > Signed-off-by: Ralf Hoffmann > <ralf.hoffmann at allegro-packets.com > <mailto:ralf.hoffmann at allegro-packets.com>> > --- > lib/librte_eal/linuxapp/eal/eal_memory.c | 27 > +++++++++++++-------------- > 1 file changed, 13 insertions(+), 14 deletions(-) > > diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c > b/lib/librte_eal/linuxapp/eal/eal_memory.c > index ac2745e..6d01f61 100644 > --- a/lib/librte_eal/linuxapp/eal/eal_memory.c > +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c > @@ -699,25 +699,25 @@ error: > * higher address first on powerpc). We use a slow > algorithm, but we won't > * have millions of pages, and this is only done at init time. > */ > -static int > +static void > sort_by_physaddr(struct hugepage_file *hugepg_tbl, struct > hugepage_info *hpi) > { > unsigned i, j; > - int compare_idx; > + unsigned compare_idx; > uint64_t compare_addr; > struct hugepage_file tmp; > for (i = 0; i < hpi->num_pages[0]; i++) { > - compare_addr = 0; > - compare_idx = -1; > + compare_addr = hugepg_tbl[i].physaddr; > + compare_idx = i; > /* > - * browse all entries starting at 'i', and > find the > + * browse all entries starting at 'i+1', and > find the > * entry with the smallest addr > */ > - for (j=i; j< hpi->num_pages[0]; j++) { > + for (j=i + 1; j < hpi->num_pages[0]; j++) { > > Although there are many style/checkpatch issues in current code, > we try to fix them > in new patches. > In that regard, checkpatch complains about above line with: > ERROR:SPACING: spaces required around that '=' > > - if (compare_addr == 0 || > + if ( > #ifdef RTE_ARCH_PPC_64 > hugepg_tbl[j].physaddr > > compare_addr) { > #else > @@ -728,10 +728,9 @@ sort_by_physaddr(struct hugepage_file > *hugepg_tbl, struct hugepage_info *hpi) > } > } > - /* should not happen */ > - if (compare_idx == -1) { > - RTE_LOG(ERR, EAL, "%s(): error in > physaddr sorting\n", __func__); > - return -1; > + if (compare_idx == i) { > + /* no smaller page found */ > + continue; > } > /* swap the 2 entries in the table */ > @@ -741,7 +740,8 @@ sort_by_physaddr(struct hugepage_file > *hugepg_tbl, struct hugepage_info *hpi) > sizeof(struct hugepage_file)); > memcpy(&hugepg_tbl[i], &tmp, sizeof(struct > hugepage_file)); > } > - return 0; > + > + return; > } > > I reckon checkpatch is not picking this one because the > end-of-function is not part of the patch, > but it is a warning: > WARNING:RETURN_VOID: void function return statements are not > generally useful > > /* > @@ -1164,8 +1164,7 @@ rte_eal_hugepage_init(void) > goto fail; > } > - if (sort_by_physaddr(&tmp_hp[hp_offset], hpi) < 0) > - goto fail; > + sort_by_physaddr(&tmp_hp[hp_offset], hpi); > #ifdef RTE_EAL_SINGLE_FILE_SEGMENTS > /* remap all hugepages into single file > segments */ > > > > Thanks, > Sergio > >