On Thu, Oct 22, 2015 at 09:51:28AM +0100, Sergio Gonzalez Monroy wrote:
> On 21/10/2015 17:34, Bruce Richardson wrote:
> >On Wed, Oct 21, 2015 at 04:22:45PM +0000, shesha Sreenivasamurthy (shesha)
> >wrote:
> >>When an application using huge-pages crash or exists, the hugetlbfs
> >>backing files are not cleaned up. This is a patch to clean those files.
> >>There are multi-process DPDK applications that may be benefited by those
> >>backing files. Therefore, I have made that configurable so that the
> >>application that does not need those backing files can remove them, thus
> >>not changing the current default behavior. The application itself can
> >>clean it up, however the rationale behind DPDK cleaning it up is, DPDK
> >>created it and therefore, it is better it unlinks it.
> >>
> >>Signed-off-by: Shesha Sreenivasamurthy <shesha at cisco.com>
> >>---
> >> lib/librte_eal/common/eal_common_options.c | 12 ++++++++++++
> >> lib/librte_eal/common/eal_internal_cfg.h | 1 +
> >> lib/librte_eal/common/eal_options.h | 2 ++
> >> lib/librte_eal/linuxapp/eal/eal_memory.c | 30
> >>++++++++++++++++++++++++++++++
> >> 4 files changed, 45 insertions(+)
> >>
> ><snip>
> >>+static int
> >>+unlink_hugepage_files(struct hugepage_file *hugepg_tbl,
> >>+ unsigned num_hp_info)
> >>+{
> >>+ unsigned socket, size;
> >>+ int page, nrpages = 0;
> >>+
> >>+ /* get total number of hugepages */
> >>+ for (size = 0; size < num_hp_info; size++)
> >>+ for (socket = 0; socket < RTE_MAX_NUMA_NODES; socket++)
> >>+ nrpages +=
> >>internal_config.hugepage_info[size].num_pages[socket];
> >>+
> >>+ for (page = 0; page < nrpages; page++) {
> >>+ struct hugepage_file *hp = &hugepg_tbl[page];
> >>+ if (hp->final_va != NULL && unlink(hp->filepath)) {
> >>+ RTE_LOG(WARNING, EAL, "%s(): Removing %s failed: %s\n",
> >>+ __func__, hp->filepath, strerror(errno));
> >>+ }
> >>+ }
> >>+ return 0;
> >>+}
> >>+
> >> /*
> >> * unmaps hugepages that are not going to be used. since we originally
> >>allocate
> >> * ALL hugepages (not just those we need), additional unmapping needs to
> >>be done.
> >>@@ -1289,6 +1311,14 @@ rte_eal_hugepage_init(void)
> >> goto fail;
> >> }
> >>+ /* free the hugepage backing files */
> >>+ if (internal_config.hugepage_unlink &&
> >>+ unlink_hugepage_files(tmp_hp,
> >>+ internal_config.num_hugepage_sizes) < 0) {
> >>+ RTE_LOG(ERR, EAL, "Unlinking hugepage backing files
> >>failed!\n");
> >>+ goto fail;
> >>+ }
> >>+
> >Sorry for the late comment, but...
> >
> >Rather than adding a whole new function to be called here, can the same
> >effect
> >not be got by adding in 2/3 lines like:
> > if (internal_config.hugepage_unlink)
> > unlink(hugetlb[i].filepath)
> >
> >at line 409 of eal_memory.c where were have done our final mmap of the file.
> >[You also need the same couple of lines for the 32-bit special case at line
> >351].
> >It would be a shorter diff.
> >
> >/Bruce
> If you wanted to avoid the extra function call, I might be cleaner to just
> unlink all files when
> doing unmap_all_hugepages_orig.
> My two cents: I think it would be easier to read/debug having a function
> that "unlinks files" instead
> of unlinking files at different points in map_all_hugepages.
>
> Unfortunately the proposed approach does not work for all cases:
> - If we have single file segment, map_all_hugepages does not get call a
> second time, instead we call
> remap_all_hugepages
> - If we use options -m or --socket-mem, because unmap_unneeded_hugepages
> does not expect files
> already unlinked, it will fail when trying to unlink unneeded hugepage
> files.
>
> The current patch would work as we only unlink after
> unmap_unneeded_hugepages.
>
> Sergio
>
I don't mind much where the functionality is done - I mostly care about reducing
the code diff. I'd prefer the unlink to be done either with the mmap of unmap,
but
I won't lose any sleep if everyone else prefers a separate function for it.
/Bruce
