* Re: Avoid reading /sys/kernel/mm/transparent_hugepage/? [not found] <CAMe9rOrk20jCXO_Bun4LK6M3fd_8HzEtAu94FW+-xSkwNiOt7w@mail.gmail.com> @ 2026-04-10 7:27 ` Florian Weimer 2026-04-10 7:40 ` H.J. Lu 0 siblings, 1 reply; 4+ messages in thread From: Florian Weimer @ 2026-04-10 7:27 UTC (permalink / raw) To: H.J. Lu; +Cc: GNU C Library, Alexey Dobriyan, linux-kernel, linux-arch, linux-api * H. J. Lu: > To enable THP segment load, ld.so opens and reads 2 files under > /sys/kernel/mm/transparent_hugepage/. This requires mounting > /sys and is expensive. Is it possible to put such info in vDSO? Alexey Dobriyan proposed adding AT_PAGE_SHIFT_LIST to the auxiliary vector a while back, but I don't know the status of that. Thanks, Florian ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Avoid reading /sys/kernel/mm/transparent_hugepage/? 2026-04-10 7:27 ` Avoid reading /sys/kernel/mm/transparent_hugepage/? Florian Weimer @ 2026-04-10 7:40 ` H.J. Lu 2026-04-10 8:37 ` Alexey Dobriyan 0 siblings, 1 reply; 4+ messages in thread From: H.J. Lu @ 2026-04-10 7:40 UTC (permalink / raw) To: Florian Weimer Cc: GNU C Library, Alexey Dobriyan, linux-kernel, linux-arch, linux-api On Fri, Apr 10, 2026 at 3:28 PM Florian Weimer <fweimer@redhat.com> wrote: > > * H. J. Lu: > > > To enable THP segment load, ld.so opens and reads 2 files under > > /sys/kernel/mm/transparent_hugepage/. This requires mounting > > /sys and is expensive. Is it possible to put such info in vDSO? > > Alexey Dobriyan proposed adding AT_PAGE_SHIFT_LIST to the auxiliary Does it cover [hjl@gnu-tgl-3 linux]$ cat /sys/kernel/mm/transparent_hugepage/hpage_pmd_size 2097152 [hjl@gnu-tgl-3 linux]$ > vector a while back, but I don't know the status of that. > How can we get [hjl@gnu-tgl-3 linux]$ cat /sys/kernel/mm/transparent_hugepage/enabled always [madvise] never [hjl@gnu-tgl-3 linux]$ -- H.J. ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Avoid reading /sys/kernel/mm/transparent_hugepage/? 2026-04-10 7:40 ` H.J. Lu @ 2026-04-10 8:37 ` Alexey Dobriyan 2026-04-11 0:12 ` H.J. Lu 0 siblings, 1 reply; 4+ messages in thread From: Alexey Dobriyan @ 2026-04-10 8:37 UTC (permalink / raw) To: H.J. Lu; +Cc: Florian Weimer, GNU C Library, linux-kernel, linux-arch, linux-api On Fri, Apr 10, 2026 at 03:40:30PM +0800, H.J. Lu wrote: > On Fri, Apr 10, 2026 at 3:28 PM Florian Weimer <fweimer@redhat.com> wrote: > > > > * H. J. Lu: > > > > > To enable THP segment load, ld.so opens and reads 2 files under > > > /sys/kernel/mm/transparent_hugepage/. This requires mounting > > > /sys and is expensive. Is it possible to put such info in vDSO? > > > > Alexey Dobriyan proposed adding AT_PAGE_SHIFT_LIST to the auxiliary > > Does it cover > > [hjl@gnu-tgl-3 linux]$ cat /sys/kernel/mm/transparent_hugepage/hpage_pmd_size > 2097152 > [hjl@gnu-tgl-3 linux]$ > > > vector a while back, but I don't know the status of that. Status: nothing happened. > How can we get > > [hjl@gnu-tgl-3 linux]$ cat /sys/kernel/mm/transparent_hugepage/enabled > always [madvise] never > [hjl@gnu-tgl-3 linux]$ This is not covered, see the link: https://lore.kernel.org/lkml/ecb049aa-bcac-45c7-bbb1-4612d094935a@p183/ PAGE_SHIFT_MASK should be folded into system call probably. ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Avoid reading /sys/kernel/mm/transparent_hugepage/? 2026-04-10 8:37 ` Alexey Dobriyan @ 2026-04-11 0:12 ` H.J. Lu 0 siblings, 0 replies; 4+ messages in thread From: H.J. Lu @ 2026-04-11 0:12 UTC (permalink / raw) To: Alexey Dobriyan Cc: Florian Weimer, GNU C Library, linux-kernel, linux-arch, linux-api On Fri, Apr 10, 2026 at 4:35 PM Alexey Dobriyan <adobriyan@gmail.com> wrote: > > On Fri, Apr 10, 2026 at 03:40:30PM +0800, H.J. Lu wrote: > > On Fri, Apr 10, 2026 at 3:28 PM Florian Weimer <fweimer@redhat.com> wrote: > > > > > > * H. J. Lu: > > > > > > > To enable THP segment load, ld.so opens and reads 2 files under > > > > /sys/kernel/mm/transparent_hugepage/. This requires mounting > > > > /sys and is expensive. Is it possible to put such info in vDSO? > > > > > > Alexey Dobriyan proposed adding AT_PAGE_SHIFT_LIST to the auxiliary > > > > Does it cover > > > > [hjl@gnu-tgl-3 linux]$ cat /sys/kernel/mm/transparent_hugepage/hpage_pmd_size > > 2097152 > > [hjl@gnu-tgl-3 linux]$ > > > > > vector a while back, but I don't know the status of that. > > Status: nothing happened. > > > How can we get > > > > [hjl@gnu-tgl-3 linux]$ cat /sys/kernel/mm/transparent_hugepage/enabled > > always [madvise] never > > [hjl@gnu-tgl-3 linux]$ > > This is not covered, see the link: > https://lore.kernel.org/lkml/ecb049aa-bcac-45c7-bbb1-4612d094935a@p183/ > > PAGE_SHIFT_MASK should be folded into system call probably. We need a fast way to check THP status for THP segment load. A system call to return /sys/kernel/mm/transparent_hugepage/enabled and /sys/kernel/mm/transparent_hugepage/hpage_pmd_size should work. -- H.J. ^ permalink raw reply [flat|nested] 4+ messages in thread
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[not found] <CAMe9rOrk20jCXO_Bun4LK6M3fd_8HzEtAu94FW+-xSkwNiOt7w@mail.gmail.com>
2026-04-10 7:27 ` Avoid reading /sys/kernel/mm/transparent_hugepage/? Florian Weimer
2026-04-10 7:40 ` H.J. Lu
2026-04-10 8:37 ` Alexey Dobriyan
2026-04-11 0:12 ` H.J. Lu
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