Sergio,
Your comment regarding remap_all_functions is correct and can be fixed
by unlinking in remap_all_hugepages() too. However, regarding you comment
that ?unmap_unneeded_hugepages? will fail ? in the
unmap_unneeded_hugepages() we do not unlink if final_va is equal to NULL
guarded by RTE_EAL_SINGLE_FILE_SEGMENTS. My testing did not catch as
RTE_EAL_SINGLE_FILE_SEGMENTS was set. Is there any reason why we should
not skip unlinking if final_va is null always (removing ifdef
RTE_EAL_SINGLE_FILE_SEGMENTS) ?
However, if you think having a separate function is better, I am all for
it.
--
- Thanks
char * (*shesha) (uint64_t cache, uint8_t F00D)
{ return 0x0000C0DE; }
-----Original Message-----
From: Sergio Gonzalez Monroy <sergio.gonzalez.mon...@intel.com>
Date: Thursday, October 22, 2015 at 1:51 AM
To: Cisco Employee <shesha at cisco.com>
Cc: "dev at dpdk.org" <dev at dpdk.org>, Bruce Richardson
<bruce.richardson at intel.com>
Subject: Re: [dpdk-dev] [PATCH v3] mem: command line option to delete
hugepage backing files
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
