Re: [libvirt] [PATCH 7/8] save: add virDirectFd wrapper type

O_DIRECT has stringent requirements - I/O must occur with buffers that have both alignment and size as multiples of the file system block size (used to be 512 bytes, but these days, 4k is safer, and 64k allows for better throughput). Rather than make lots of changes at each site that wants to use O_DIRECT, it is easier to offload the work through a helper process that mirrors the I/O between a pipe and the actual direct fd, so that the other end of the pipe no longer has to worry about constraints. * src/util/virdirect.h: New file. * src/util/virdirect.c: Likewise. * src/Makefile.am (UTIL_SOURCES): Build them. * src/libvirt_private.syms: Export new symbols. * cfg.mk (useless_free_options): Add to list. * po/POTFILES.in: Translate new file. --- cfg.mk | 1 + po/POTFILES.in | 1 + src/Makefile.am | 1 + src/libvirt_private.syms | 6 ++ src/util/virdirect.c | 149 ++++++++++++++++++++++++++++++++++++++++++++++ src/util/virdirect.h | 37 +++++++++++ 6 files changed, 195 insertions(+), 0 deletions(-) create mode 100644 src/util/virdirect.c create mode 100644 src/util/virdirect.h diff --git a/cfg.mk b/cfg.mk index 2873177..69d2b6a 100644 --- a/cfg.mk +++ b/cfg.mk @@ -97,6 +97,7 @@ useless_free_options = \ --name=virCommandFree \ --name=virConfFreeList \ --name=virConfFreeValue \ + --name=virDirectFdFree \ --name=virDomainChrDefFree \ --name=virDomainChrSourceDefFree \ --name=virDomainControllerDefFree \ diff --git a/po/POTFILES.in b/po/POTFILES.in index 5782cbf..ad031f3 100644 --- a/po/POTFILES.in +++ b/po/POTFILES.in @@ -122,6 +122,7 @@ src/util/storage_file.c src/util/sysinfo.c src/util/util.c src/util/viraudit.c +src/util/virdirect.c src/util/virterror.c src/util/xml.c src/vbox/vbox_MSCOMGlue.c diff --git a/src/Makefile.am b/src/Makefile.am index d19d1ca..ce041b4 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -80,6 +80,7 @@ UTIL_SOURCES = \ util/uuid.c util/uuid.h \ util/util.c util/util.h \ util/viraudit.c util/viraudit.h \ + util/virdirect.c util/virdirect.h \ util/xml.c util/xml.h \ util/virterror.c util/virterror_internal.h diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms index f95d341..c78485d 100644 --- a/src/libvirt_private.syms +++ b/src/libvirt_private.syms @@ -1085,6 +1085,12 @@ virAuditOpen; virAuditSend; +# virdirect.h +virDirectFdClose; +virDirectFdFree; +virDirectFdNew;