* [dpdk-dev] [PATCH] mem: fix free segment when using huge-unlink option
@ 2021-02-22 10:41 Roy Shterman
2021-02-22 15:53 ` Burakov, Anatoly
0 siblings, 1 reply; 3+ messages in thread
From: Roy Shterman @ 2021-02-22 10:41 UTC (permalink / raw)
To: anatoly.burakov; +Cc: dev, yuval, aviv.bendavid, Roy Shterman
When using huge_unlink we unlink the segment right
after allocation. Although we unlink the file we keep
the fd in fd_list so file still exist just the path deleted.
When freeing the hugepage we need to close the fd and assign
it with (-1) in fd_list for the page to be released.
The current flow fails rte_malloc in the following flow when working
with --huge-unlink option:
1. alloc_seg() for segment A -
We allocate segment, unlink the path to the segment
and keep the file descriptor in fd_list.
2. free_seg() for segment A -
We clear the segment metadata and return - without closing fd
or assigning (-1) in fd list.
3. alloc_seg() for segment A again -
We find segment A as available, try to allocate it,
find the old fd in fd_list try to unlink it
as part of alloc_seg() but failed because path doesn't exist.
The impact of such error is falsly failing rte_malloc()
although we have hugepages available.
Fixes: d435aad37da7 ("mem: support --huge-unlink mode")
Signed-off-by: Roy Shterman <roy.shterman@vastdata.com>
---
lib/librte_eal/linux/eal_memalloc.c | 14 ++------------
1 file changed, 2 insertions(+), 12 deletions(-)
diff --git a/lib/librte_eal/linux/eal_memalloc.c b/lib/librte_eal/linux/eal_memalloc.c
index 6dc1b2bae..c590d6043 100644
--- a/lib/librte_eal/linux/eal_memalloc.c
+++ b/lib/librte_eal/linux/eal_memalloc.c
@@ -709,7 +709,6 @@ free_seg(struct rte_memseg *ms, struct hugepage_info *hi,
uint64_t map_offset;
char path[PATH_MAX];
int fd, ret = 0;
- bool exit_early;
const struct internal_config *internal_conf =
eal_get_internal_configuration();
@@ -725,17 +724,8 @@ free_seg(struct rte_memseg *ms, struct hugepage_info *hi,
eal_mem_set_dump(ms->addr, ms->len, false);
- exit_early = false;
-
/* if we're using anonymous hugepages, nothing to be done */
- if (internal_conf->in_memory && !memfd_create_supported)
- exit_early = true;
-
- /* if we've already unlinked the page, nothing needs to be done */
- if (!internal_conf->in_memory && internal_conf->hugepage_unlink)
- exit_early = true;
-
- if (exit_early) {
+ if (internal_conf->in_memory && !memfd_create_supported) {
memset(ms, 0, sizeof(*ms));
return 0;
}
@@ -761,7 +751,7 @@ free_seg(struct rte_memseg *ms, struct hugepage_info *hi,
/* if we're able to take out a write lock, we're the last one
* holding onto this page.
*/
- if (!internal_conf->in_memory) {
+ if (!internal_conf->in_memory && !internal_conf->hugepage_unlink) {
ret = lock(fd, LOCK_EX);
if (ret >= 0) {
/* no one else is using this page */
--
2.24.1
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [dpdk-dev] [PATCH] mem: fix free segment when using huge-unlink option
2021-02-22 10:41 [dpdk-dev] [PATCH] mem: fix free segment when using huge-unlink option Roy Shterman
@ 2021-02-22 15:53 ` Burakov, Anatoly
2021-02-28 13:21 ` Roy Shterman
0 siblings, 1 reply; 3+ messages in thread
From: Burakov, Anatoly @ 2021-02-22 15:53 UTC (permalink / raw)
To: Roy Shterman; +Cc: dev, yuval, aviv.bendavid
On 22-Feb-21 10:41 AM, Roy Shterman wrote:
> When using huge_unlink we unlink the segment right
> after allocation. Although we unlink the file we keep
> the fd in fd_list so file still exist just the path deleted.
> When freeing the hugepage we need to close the fd and assign
> it with (-1) in fd_list for the page to be released.
>
> The current flow fails rte_malloc in the following flow when working
> with --huge-unlink option:
> 1. alloc_seg() for segment A -
> We allocate segment, unlink the path to the segment
> and keep the file descriptor in fd_list.
> 2. free_seg() for segment A -
> We clear the segment metadata and return - without closing fd
> or assigning (-1) in fd list.
> 3. alloc_seg() for segment A again -
> We find segment A as available, try to allocate it,
> find the old fd in fd_list try to unlink it
> as part of alloc_seg() but failed because path doesn't exist.
>
> The impact of such error is falsly failing rte_malloc()
> although we have hugepages available.
>
> Fixes: d435aad37da7 ("mem: support --huge-unlink mode")
>
> Signed-off-by: Roy Shterman <roy.shterman@vastdata.com>
Cc: stable@dpdk.org
Provisionally, patch looks fine, but i'll have to have a closer look.
--
Thanks,
Anatoly
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [dpdk-dev] [PATCH] mem: fix free segment when using huge-unlink option
2021-02-22 15:53 ` Burakov, Anatoly
@ 2021-02-28 13:21 ` Roy Shterman
0 siblings, 0 replies; 3+ messages in thread
From: Roy Shterman @ 2021-02-28 13:21 UTC (permalink / raw)
To: Burakov, Anatoly; +Cc: dev, Yuval Mintz, Aviv Ben David
On Mon, Feb 22, 2021 at 5:53 PM Burakov, Anatoly <anatoly.burakov@intel.com>
wrote:
> On 22-Feb-21 10:41 AM, Roy Shterman wrote:
> > When using huge_unlink we unlink the segment right
> > after allocation. Although we unlink the file we keep
> > the fd in fd_list so file still exist just the path deleted.
> > When freeing the hugepage we need to close the fd and assign
> > it with (-1) in fd_list for the page to be released.
> >
> > The current flow fails rte_malloc in the following flow when working
> > with --huge-unlink option:
> > 1. alloc_seg() for segment A -
> > We allocate segment, unlink the path to the segment
> > and keep the file descriptor in fd_list.
> > 2. free_seg() for segment A -
> > We clear the segment metadata and return - without closing fd
> > or assigning (-1) in fd list.
> > 3. alloc_seg() for segment A again -
> > We find segment A as available, try to allocate it,
> > find the old fd in fd_list try to unlink it
> > as part of alloc_seg() but failed because path doesn't exist.
> >
> > The impact of such error is falsly failing rte_malloc()
> > although we have hugepages available.
> >
> > Fixes: d435aad37da7 ("mem: support --huge-unlink mode")
> >
> > Signed-off-by: Roy Shterman <roy.shterman@vastdata.com>
>
> Cc: stable@dpdk.org
>
> Provisionally, patch looks fine, but i'll have to have a closer look.
>
Hi Anatoly,
Do I need to send this patch also to stable or it will happen automatically
if the patch will reach the next release candidate?
Also I wonder if you had more time to review this one?
>
> --
> Thanks,
> Anatoly
>
Thanks,
Roy
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-02-28 14:38 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-02-22 10:41 [dpdk-dev] [PATCH] mem: fix free segment when using huge-unlink option Roy Shterman
2021-02-22 15:53 ` Burakov, Anatoly
2021-02-28 13:21 ` Roy Shterman
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