* [PATCH v2] madvise: MADV_SOFT_OFFLINE requests can return -EBUSY @ 2024-11-26 16:12 tyberry 2024-11-28 11:35 ` Alejandro Colomar 0 siblings, 1 reply; 6+ messages in thread From: tyberry @ 2024-11-26 16:12 UTC (permalink / raw) To: Alejandro Colomar; +Cc: linux-man, lgoncalv If the page could not be offlined madvise will return -EBUSY. This might occur if the page is currently in use or locked. Signed-off-by: Tyonnchie Berry <tyberry@redhat.com> --- diff --git a/man/man2/madvise.2 b/man/man2/madvise.2 index 4f2210ee2..c10dcd599 100644 --- a/man/man2/madvise.2 +++ b/man/man2/madvise.2 @@ -702,6 +702,13 @@ The map exists, but the area maps something that isn't a file. .BR MADV_COLLAPSE ) Could not charge hugepage to cgroup: cgroup limit exceeded. .TP +.B EBUSY +(for +.B MADV_SOFT_OFFLINE ) +If any pages within the add+length range could not be offlined, +madvise will return -EBUSY. +This might occur if the page is currently in use or locked. +.TP .B EFAULT .I advice is ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH v2] madvise: MADV_SOFT_OFFLINE requests can return -EBUSY 2024-11-26 16:12 [PATCH v2] madvise: MADV_SOFT_OFFLINE requests can return -EBUSY tyberry @ 2024-11-28 11:35 ` Alejandro Colomar 2024-11-29 21:43 ` Luis Claudio R. Goncalves 0 siblings, 1 reply; 6+ messages in thread From: Alejandro Colomar @ 2024-11-28 11:35 UTC (permalink / raw) To: tyberry; +Cc: linux-man, lgoncalv [-- Attachment #1: Type: text/plain, Size: 1058 bytes --] Hi Tyonnchie, On Tue, Nov 26, 2024 at 11:12:03AM -0500, tyberry@redhat.com wrote: > If the page could not be offlined madvise will return -EBUSY. This might occur if the page is currently in use or locked. Could you show this in a small example program (if possible)? Like 30 lines or so. If not, it's okay. Have a lovely day! Alex > > Signed-off-by: Tyonnchie Berry <tyberry@redhat.com> > > --- > > diff --git a/man/man2/madvise.2 b/man/man2/madvise.2 > index 4f2210ee2..c10dcd599 100644 > --- a/man/man2/madvise.2 > +++ b/man/man2/madvise.2 > @@ -702,6 +702,13 @@ The map exists, but the area maps something that isn't a file. > .BR MADV_COLLAPSE ) > Could not charge hugepage to cgroup: cgroup limit exceeded. > .TP > +.B EBUSY > +(for > +.B MADV_SOFT_OFFLINE ) > +If any pages within the add+length range could not be offlined, > +madvise will return -EBUSY. > +This might occur if the page is currently in use or locked. > +.TP > .B EFAULT > .I advice > is > -- <https://www.alejandro-colomar.es/> [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 833 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] madvise: MADV_SOFT_OFFLINE requests can return -EBUSY 2024-11-28 11:35 ` Alejandro Colomar @ 2024-11-29 21:43 ` Luis Claudio R. Goncalves 2024-12-04 20:35 ` Alejandro Colomar 0 siblings, 1 reply; 6+ messages in thread From: Luis Claudio R. Goncalves @ 2024-11-29 21:43 UTC (permalink / raw) To: Alejandro Colomar; +Cc: tyberry, linux-man [-- Attachment #1: Type: text/plain, Size: 2932 bytes --] On Thu, Nov 28, 2024 at 12:35:48PM +0100, Alejandro Colomar wrote: > Hi Tyonnchie, > > On Tue, Nov 26, 2024 at 11:12:03AM -0500, tyberry@redhat.com wrote: > > If the page could not be offlined madvise will return -EBUSY. This might occur if the page is currently in use or locked. > > Could you show this in a small example program (if possible)? > Like 30 lines or so. If not, it's okay. Hi Alejandro! Given the ongoing holidays, let me take the liberty of giving some context in order to keep the conversation going. We received reports of failed LTP madvise11[1] tests. The errors looked like this: madvise11.c:409: TINFO: Spawning 4 threads, with a total of 640 memory pages madvise11.c:132: TFAIL: madvise failed: EBUSY (16) madvise11.c:163: TINFO: Thread [0] returned 16, failed. madvise11.c:191: TFAIL: thread [0] - exited with errors madvise11.c:163: TINFO: Thread [2] returned 0, succeeded. madvise11.c:163: TINFO: Thread [3] returned 0, succeeded. madvise11.c:163: TINFO: Thread [1] returned 0, succeeded. madvise11.c:361: TINFO: Restore 629 Soft-offlined pages madvise11.c:290: TWARN: write(3,0x7ffce114b8a0,8) failed: EBUSY (16) Clearly the problem had to do with -EBUSY being returned by a madvise() operation. The bug was initially reported on kernels with PREEMPT_RT enabled but we soon observed that the problem also happened with the stock kernel, though requiring more repetitions to trigger issue. After debug and investigation we observed that the -EBUSY return was a valid case in the kernel code and was not being handled by the test. A fix was sent to the LTP project by Li Wang[2], specifically for the madvise11 test. In this process, we noticed that the man pages did not mention -EBUSY as a possible result of a failed offlining operation, as described by Tyonnchie. I hope this helps! Best regards, Luis [1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/madvise/madvise11.c [2] https://lists.linux.it/pipermail/ltp/2024-May/038310.html > Have a lovely day! > Alex > > > > > Signed-off-by: Tyonnchie Berry <tyberry@redhat.com> > > > > --- > > > > diff --git a/man/man2/madvise.2 b/man/man2/madvise.2 > > index 4f2210ee2..c10dcd599 100644 > > --- a/man/man2/madvise.2 > > +++ b/man/man2/madvise.2 > > @@ -702,6 +702,13 @@ The map exists, but the area maps something that isn't a file. > > .BR MADV_COLLAPSE ) > > Could not charge hugepage to cgroup: cgroup limit exceeded. > > .TP > > +.B EBUSY > > +(for > > +.B MADV_SOFT_OFFLINE ) > > +If any pages within the add+length range could not be offlined, > > +madvise will return -EBUSY. > > +This might occur if the page is currently in use or locked. > > +.TP > > .B EFAULT > > .I advice > > is > > > > -- > <https://www.alejandro-colomar.es/> ---end quoted text--- [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 833 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] madvise: MADV_SOFT_OFFLINE requests can return -EBUSY 2024-11-29 21:43 ` Luis Claudio R. Goncalves @ 2024-12-04 20:35 ` Alejandro Colomar 2024-12-04 20:45 ` Luis Claudio R. Goncalves 0 siblings, 1 reply; 6+ messages in thread From: Alejandro Colomar @ 2024-12-04 20:35 UTC (permalink / raw) To: Luis Claudio R. Goncalves; +Cc: tyberry, linux-man [-- Attachment #1: Type: text/plain, Size: 3510 bytes --] Hi Luis, Tyonnchie, On Fri, Nov 29, 2024 at 06:43:39PM -0300, Luis Claudio R. Goncalves wrote: > On Thu, Nov 28, 2024 at 12:35:48PM +0100, Alejandro Colomar wrote: > > Hi Tyonnchie, > > > > On Tue, Nov 26, 2024 at 11:12:03AM -0500, tyberry@redhat.com wrote: > > > If the page could not be offlined madvise will return -EBUSY. This might occur if the page is currently in use or locked. > > > > Could you show this in a small example program (if possible)? > > Like 30 lines or so. If not, it's okay. > > Hi Alejandro! > > Given the ongoing holidays, let me take the liberty of giving some context > in order to keep the conversation going. > > We received reports of failed LTP madvise11[1] tests. The errors looked > like this: > > madvise11.c:409: TINFO: Spawning 4 threads, with a total of 640 memory pages > madvise11.c:132: TFAIL: madvise failed: EBUSY (16) > madvise11.c:163: TINFO: Thread [0] returned 16, failed. > madvise11.c:191: TFAIL: thread [0] - exited with errors > madvise11.c:163: TINFO: Thread [2] returned 0, succeeded. > madvise11.c:163: TINFO: Thread [3] returned 0, succeeded. > madvise11.c:163: TINFO: Thread [1] returned 0, succeeded. > madvise11.c:361: TINFO: Restore 629 Soft-offlined pages > madvise11.c:290: TWARN: write(3,0x7ffce114b8a0,8) failed: EBUSY (16) > > Clearly the problem had to do with -EBUSY being returned by a madvise() > operation. The bug was initially reported on kernels with PREEMPT_RT > enabled but we soon observed that the problem also happened with the stock > kernel, though requiring more repetitions to trigger issue. > > After debug and investigation we observed that the -EBUSY return was a valid > case in the kernel code and was not being handled by the test. A fix was > sent to the LTP project by Li Wang[2], specifically for the madvise11 test. > > In this process, we noticed that the man pages did not mention -EBUSY as a > possible result of a failed offlining operation, as described by Tyonnchie. > > I hope this helps! Thanks! I've applied the patch, with some tweaks: <https://www.alejandro-colomar.es/src/alx/linux/man-pages/man-pages.git/commit/?h=contrib&id=3205359a3a7079d9d40a50388e851874729a827a> I added an Acked-by on your behalf, Luis. Have a lovely night! Alex > > Best regards, > Luis > > [1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/madvise/madvise11.c > [2] https://lists.linux.it/pipermail/ltp/2024-May/038310.html > > > > Have a lovely day! > > Alex > > > > > > > > Signed-off-by: Tyonnchie Berry <tyberry@redhat.com> > > > > > > --- > > > > > > diff --git a/man/man2/madvise.2 b/man/man2/madvise.2 > > > index 4f2210ee2..c10dcd599 100644 > > > --- a/man/man2/madvise.2 > > > +++ b/man/man2/madvise.2 > > > @@ -702,6 +702,13 @@ The map exists, but the area maps something that isn't a file. > > > .BR MADV_COLLAPSE ) > > > Could not charge hugepage to cgroup: cgroup limit exceeded. > > > .TP > > > +.B EBUSY > > > +(for > > > +.B MADV_SOFT_OFFLINE ) > > > +If any pages within the add+length range could not be offlined, > > > +madvise will return -EBUSY. > > > +This might occur if the page is currently in use or locked. > > > +.TP > > > .B EFAULT > > > .I advice > > > is > > > > > > > -- > > <https://www.alejandro-colomar.es/> > > > ---end quoted text--- -- <https://www.alejandro-colomar.es/> [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 833 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] madvise: MADV_SOFT_OFFLINE requests can return -EBUSY 2024-12-04 20:35 ` Alejandro Colomar @ 2024-12-04 20:45 ` Luis Claudio R. Goncalves 2024-12-04 20:51 ` Alejandro Colomar 0 siblings, 1 reply; 6+ messages in thread From: Luis Claudio R. Goncalves @ 2024-12-04 20:45 UTC (permalink / raw) To: Alejandro Colomar; +Cc: tyberry, linux-man [-- Attachment #1: Type: text/plain, Size: 3909 bytes --] On Wed, Dec 04, 2024 at 09:35:20PM +0100, Alejandro Colomar wrote: > Hi Luis, Tyonnchie, > > On Fri, Nov 29, 2024 at 06:43:39PM -0300, Luis Claudio R. Goncalves wrote: > > On Thu, Nov 28, 2024 at 12:35:48PM +0100, Alejandro Colomar wrote: > > > Hi Tyonnchie, > > > > > > On Tue, Nov 26, 2024 at 11:12:03AM -0500, tyberry@redhat.com wrote: > > > > If the page could not be offlined madvise will return -EBUSY. This might occur if the page is currently in use or locked. > > > > > > Could you show this in a small example program (if possible)? > > > Like 30 lines or so. If not, it's okay. > > > > Hi Alejandro! > > > > Given the ongoing holidays, let me take the liberty of giving some context > > in order to keep the conversation going. > > > > We received reports of failed LTP madvise11[1] tests. The errors looked > > like this: > > > > madvise11.c:409: TINFO: Spawning 4 threads, with a total of 640 memory pages > > madvise11.c:132: TFAIL: madvise failed: EBUSY (16) > > madvise11.c:163: TINFO: Thread [0] returned 16, failed. > > madvise11.c:191: TFAIL: thread [0] - exited with errors > > madvise11.c:163: TINFO: Thread [2] returned 0, succeeded. > > madvise11.c:163: TINFO: Thread [3] returned 0, succeeded. > > madvise11.c:163: TINFO: Thread [1] returned 0, succeeded. > > madvise11.c:361: TINFO: Restore 629 Soft-offlined pages > > madvise11.c:290: TWARN: write(3,0x7ffce114b8a0,8) failed: EBUSY (16) > > > > Clearly the problem had to do with -EBUSY being returned by a madvise() > > operation. The bug was initially reported on kernels with PREEMPT_RT > > enabled but we soon observed that the problem also happened with the stock > > kernel, though requiring more repetitions to trigger issue. > > > > After debug and investigation we observed that the -EBUSY return was a valid > > case in the kernel code and was not being handled by the test. A fix was > > sent to the LTP project by Li Wang[2], specifically for the madvise11 test. > > > > In this process, we noticed that the man pages did not mention -EBUSY as a > > possible result of a failed offlining operation, as described by Tyonnchie. > > > > I hope this helps! > > Thanks! I've applied the patch, with some tweaks: > <https://www.alejandro-colomar.es/src/alx/linux/man-pages/man-pages.git/commit/?h=contrib&id=3205359a3a7079d9d40a50388e851874729a827a> > > I added an Acked-by on your behalf, Luis. Thank you! You have all my respect for the great work you and many others do with the man pages! Luis > Have a lovely night! > Alex > > > > > Best regards, > > Luis > > > > [1] https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/madvise/madvise11.c > > [2] https://lists.linux.it/pipermail/ltp/2024-May/038310.html > > > > > > > Have a lovely day! > > > Alex > > > > > > > > > > > Signed-off-by: Tyonnchie Berry <tyberry@redhat.com> > > > > > > > > --- > > > > > > > > diff --git a/man/man2/madvise.2 b/man/man2/madvise.2 > > > > index 4f2210ee2..c10dcd599 100644 > > > > --- a/man/man2/madvise.2 > > > > +++ b/man/man2/madvise.2 > > > > @@ -702,6 +702,13 @@ The map exists, but the area maps something that isn't a file. > > > > .BR MADV_COLLAPSE ) > > > > Could not charge hugepage to cgroup: cgroup limit exceeded. > > > > .TP > > > > +.B EBUSY > > > > +(for > > > > +.B MADV_SOFT_OFFLINE ) > > > > +If any pages within the add+length range could not be offlined, > > > > +madvise will return -EBUSY. > > > > +This might occur if the page is currently in use or locked. > > > > +.TP > > > > .B EFAULT > > > > .I advice > > > > is > > > > > > > > > > -- > > > <https://www.alejandro-colomar.es/> > > > > > > ---end quoted text--- > > > > -- > <https://www.alejandro-colomar.es/> ---end quoted text--- [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 833 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v2] madvise: MADV_SOFT_OFFLINE requests can return -EBUSY 2024-12-04 20:45 ` Luis Claudio R. Goncalves @ 2024-12-04 20:51 ` Alejandro Colomar 0 siblings, 0 replies; 6+ messages in thread From: Alejandro Colomar @ 2024-12-04 20:51 UTC (permalink / raw) To: Luis Claudio R. Goncalves; +Cc: tyberry, linux-man [-- Attachment #1: Type: text/plain, Size: 586 bytes --] On Wed, Dec 04, 2024 at 05:45:20PM -0300, Luis Claudio R. Goncalves wrote: [...] > > > I hope this helps! > > > > Thanks! I've applied the patch, with some tweaks: > > <https://www.alejandro-colomar.es/src/alx/linux/man-pages/man-pages.git/commit/?h=contrib&id=3205359a3a7079d9d40a50388e851874729a827a> > > > > I added an Acked-by on your behalf, Luis. > > Thank you! > > You have all my respect for the great work you and many others do > with the man pages! Thank you very much! :-} Cheers, Alex > > Luis -- <https://www.alejandro-colomar.es/> [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 833 bytes --] ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2024-12-04 20:51 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2024-11-26 16:12 [PATCH v2] madvise: MADV_SOFT_OFFLINE requests can return -EBUSY tyberry 2024-11-28 11:35 ` Alejandro Colomar 2024-11-29 21:43 ` Luis Claudio R. Goncalves 2024-12-04 20:35 ` Alejandro Colomar 2024-12-04 20:45 ` Luis Claudio R. Goncalves 2024-12-04 20:51 ` Alejandro Colomar
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