Signed-off-by: Brian Geffon <bgeffon@xxxxxxxxxx> --- man2/mremap.2 | 30 +++++++++++++++++++++++++++++- 1 file changed, 29 insertions(+), 1 deletion(-) diff --git a/man2/mremap.2 b/man2/mremap.2 index d73fb64fa..54ec67b20 100644 --- a/man2/mremap.2 +++ b/man2/mremap.2 @@ -26,7 +26,8 @@ .\" 1996-04-12 Tom Bjorkholm <tomb@xxxxxxxxx> .\" Update for Linux 1.3.87 and later .\" 2005-10-11 mtk: Added NOTES for MREMAP_FIXED; revised EINVAL text. -.\" +.\" 2020-02-05 Brian Geffon <bgeffon@xxxxxxxxxx> +.\" Update for MREMAP_DONTUNMAP. .TH MREMAP 2 2019-03-06 "Linux" "Linux Programmer's Manual" .SH NAME mremap \- remap a virtual memory address @@ -129,6 +130,13 @@ If is specified, then .B MREMAP_MAYMOVE must also be specified. +.TP +.BR MREMAP_DONTUNMAP " (since Linux 5.7)" +This flag which must be used in conjuction with +.B MREMAP_MAYMOVE +remaps a mapping to a new address and it does not unmap the mapping at \fIold_address\fP. This flag can only be used with private anonymous mappings. Any access to the range specified at \fIold_address\fP after completion will result in a page fault. If a +.BR userfaultfd (2) +was registered on the mapping specified by \fIold_address\fP it will continue to watch that mapping for faults. .PP If the memory segment specified by .I old_address @@ -176,6 +184,8 @@ a value other than .B MREMAP_MAYMOVE or .B MREMAP_FIXED +or +.B MREMAP_DONTUNMAP was specified in .IR flags ; .IP * @@ -197,9 +207,17 @@ and .IR old_size ; .IP * .B MREMAP_FIXED +or +.B MREMAP_DONTUNMAP was specified without also specifying .BR MREMAP_MAYMOVE ; .IP * +.B MREMAP_DONTUNMAP +was specified with an \fIold_address\fP that was not private anonymous; +.IP * +.B MREMAP_DONTUNMAP +was specified and \fIold_size\fP was not equal to \fInew_size\fP; +.IP * \fIold_size\fP was zero and \fIold_address\fP does not refer to a shareable mapping (but see BUGS); .IP * @@ -209,10 +227,20 @@ flag was not specified. .RE .TP .B ENOMEM +Not enough memory was available to complete the operation. +Possible causes are: +.RS +.IP * 3 The memory area cannot be expanded at the current virtual address, and the .B MREMAP_MAYMOVE flag is not set in \fIflags\fP. Or, there is not enough (virtual) memory available. +.IP * +.B MREMAP_DONTUNMAP +was used without +.B MREMAP_FIXED +causing a new mapping to be created that would exceed the virtual memory available or it would exceed the maximum number of allowed mappings. +.RE .SH CONFORMING TO This call is Linux-specific, and should not be used in programs intended to be portable. -- 2.25.0.265.gbab2e86ba0-goog
