Preview of MADV_POPULATE documentation, which is still under discussion: https://lkml.kernel.org/r/[email protected]
Once/if merged, there will be an official patch to man-page folks. Cc: Andrew Morton <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Oscar Salvador <[email protected]> Cc: Matthew Wilcox (Oracle) <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: Minchan Kim <[email protected]> Cc: Jann Horn <[email protected]> Cc: Jason Gunthorpe <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Rik van Riel <[email protected]> Cc: Michael S. Tsirkin <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Vlastimil Babka <[email protected]> Cc: Richard Henderson <[email protected]> Cc: Ivan Kokshaysky <[email protected]> Cc: Matt Turner <[email protected]> Cc: Thomas Bogendoerfer <[email protected]> Cc: "James E.J. Bottomley" <[email protected]> Cc: Helge Deller <[email protected]> Cc: Chris Zankel <[email protected]> Cc: Max Filippov <[email protected]> Cc: Mike Kravetz <[email protected]> Cc: Rolf Eike Beer <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: Linux API <[email protected]> Signed-off-by: David Hildenbrand <[email protected]> --- man2/madvise.2 | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) diff --git a/man2/madvise.2 b/man2/madvise.2 index 2af407212..ff08768a3 100644 --- a/man2/madvise.2 +++ b/man2/madvise.2 @@ -469,6 +469,48 @@ If a page is file-backed and dirty, it will be written back to the backing storage. The advice might be ignored for some pages in the range when it is not applicable. +.TP +.BR MADV_POPULATE " (since Linux 5.13) +Populate (prefault) page tables for the whole range. +Depending on the underlying mapping, preallocate memory or read the +underlying file. +Do not generate +.B SIGBUS +when populating fails, return an error instead. +The populate semantics match +.BR MAP_POPULATE +(see +.BR mmap (2)) +with the exception that +.B MADV_POPULATE +fails if there is a proplem populating page tables. +.B MADV_POPULATE +simulates user space access to all pages in the range without actually +reading/writing the pages. +For private, writable mappings, simulate a write access; for all other +mappings, simulate a read access. +.IP +If +.B MADV_POPULATE +succeeds, all page tables have been populated (prefaulted) once. +If +.B MADV_POPULATE +fails, some page tables might have been populated. +.IP +.B MADV_POPULATE +cannot be applied to +.B PROT_NONE +and special mappings marked with the kernel-internal +.B VM_PFNMAP +and +.BR VM_IO . +.IP +Note that +.B MADV_POPULATE +will ignore any poisoned pages in the range. +Similar to +.BR MAP_POPULATE , +it cannot protect from the OOM (Out Of Memory) handler killing the process. .SH RETURN VALUE On success, .BR madvise () @@ -533,6 +575,17 @@ or .BR VM_PFNMAP ranges. .TP +.B EINVAL +.I advice +is +.BR MADV_POPULATE , +but the specified address range includes +.BR PROT_NONE , +.B VM_IO +or +.B VM_PFNMAP +ranges. +.TP .B EIO (for .BR MADV_WILLNEED ) @@ -548,6 +601,12 @@ Not enough memory: paging in failed. Addresses in the specified range are not currently mapped, or are outside the address space of the process. .TP +.B ENOMEM +.I advice +is +.BR MADV_POPULATE , +but populating (prefaulting) page tables failed. +.TP .B EPERM .I advice is -- 2.29.2
