Thanks,
Feng Li
Burakov, Anatoly <anatoly.bura...@intel.com> 于2020年4月24日周五 下午7:23写道：
>
> On 24-Apr-20 11:50 AM, Li Feng wrote:
> > Currently, even though memory is mapped with PROT_NONE, this does not
> > cause it to be excluded from core dumps. This is counter-productive,
> > because in a lot of cases, this memory will go unused (e.g. when the
> > memory subsystem preallocates VA space but hasn't yet mapped physical
> > pages into it).
> >
> > Use `madvise()` call with MADV_DONTDUMP parameter to exclude the
> > unmapped memory from being dumped.
> >
> > Signed-off-by: Li Feng <fen...@smartx.com>
> > ---
> > V2:
> > - add support for freebsd.
> > - when free_seg is called, mark the memory MADV_DONTDUMP.
> > - when alloc_seg is called, mark the memory MADV_DODUMP.
>
> Isn't this v3 now?
My mistake. I will using v4 for next version.
>
> >
> > lib/librte_eal/common/eal_common_memory.c | 26 ++++++++++++++++++++++++++
> > lib/librte_eal/linux/eal_memalloc.c | 6 ++++++
> > 2 files changed, 32 insertions(+)
> >
> > diff --git a/lib/librte_eal/common/eal_common_memory.c
> > b/lib/librte_eal/common/eal_common_memory.c
> > index cc7d54e0c..83be94a20 100644
> > --- a/lib/librte_eal/common/eal_common_memory.c
> > +++ b/lib/librte_eal/common/eal_common_memory.c
> > @@ -177,6 +177,32 @@ eal_get_virtual_area(void *requested_addr, size_t
> > *size,
> > after_len = RTE_PTR_DIFF(map_end, aligned_end);
> > if (after_len > 0)
> > munmap(aligned_end, after_len);
> > +
> > + /*
> > + * Exclude this pages from a core dump.
> > + */
> > +#ifdef RTE_EXEC_ENV_LINUX
> > + if (madvise(aligned_addr, *size, MADV_DONTDUMP) != 0)
> > + RTE_LOG(DEBUG, EAL, "madvise failed: %s\n",
> > + strerror(errno));
> > +#elif RTE_EXEC_ENV_FREEBSD
> > + if (madvise(aligned_addr, *size, MADV_NOCORE) != 0)
> > + RTE_LOG(DEBUG, EAL, "madvise failed: %s\n",
> > + strerror(errno));
> > +#endif
> > + } else {
> > + /*
> > + * Exclude this pages from a core dump.
> > + */
> > +#ifdef RTE_EXEC_ENV_LINUX
> > + if (madvise(mapped_addr, map_sz, MADV_DONTDUMP) != 0)
> > + RTE_LOG(DEBUG, EAL, "madvise failed: %s\n",
> > + strerror(errno));
> > +#elif RTE_EXEC_ENV_FREEBSD
> > + if (madvise(mapped_addr, map_sz, MADV_NOCORE) != 0)
> > + RTE_LOG(DEBUG, EAL, "madvise failed: %s\n",
> > + strerror(errno));
> > +#endif
> > }
>
> DRY (Don't Repeat Yourself) :) Probably easier to do "if (!unmap) ..."
> than putting this into two places.
OK. I put this into two places, because the size is more accurate in this place.
>
> >
> > return aligned_addr;
> > diff --git a/lib/librte_eal/linux/eal_memalloc.c
> > b/lib/librte_eal/linux/eal_memalloc.c
> > index af6d0d023..9d2a6fc6f 100644
> > --- a/lib/librte_eal/linux/eal_memalloc.c
> > +++ b/lib/librte_eal/linux/eal_memalloc.c
> > @@ -571,6 +571,9 @@ alloc_seg(struct rte_memseg *ms, void *addr, int
> > socket_id,
> > goto resized;
> > }
> >
> > + if (madvise(addr, alloc_sz, MADV_DODUMP) != 0)
> > + RTE_LOG(DEBUG, EAL, "madvise failed: %s\n", strerror(errno));
> > +
>
> See discussion for v2, i believe this is unnecessary.
>
> > /* In linux, hugetlb limitations, like cgroup, are
> > * enforced at fault time instead of mmap(), even
> > * with the option of MAP_POPULATE. Kernel will send
> > @@ -687,6 +690,9 @@ free_seg(struct rte_memseg *ms, struct hugepage_info
> > *hi,
> > return -1;
> > }
> >
> > + if (madvise(ms->addr, ms->len, MADV_DONTDUMP) != 0)
> > + RTE_LOG(DEBUG, EAL, "madvise failed: %s\n", strerror(errno));
> > +
> > exit_early = false;
> >
> > /* if we're using anonymous hugepages, nothing to be done */
> >
>
>
> --
> Thanks,
> Anatoly
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