The patch titled mm: restore KERNEL_DS optimisations has been added to the -mm tree. Its filename is mm-restore-kernel_ds-optimisations.patch *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this ------------------------------------------------------ Subject: mm: restore KERNEL_DS optimisations From: Nick Piggin <npiggin@xxxxxxx> Restore the KERNEL_DS optimisation, especially helpful to the 2copy write path. This may be a pretty questionable gain in most cases, especially after the legacy 2copy write path is removed, but it doesn't cost much. Signed-off-by: Nick Piggin <npiggin@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/filemap.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) diff -puN mm/filemap.c~mm-restore-kernel_ds-optimisations mm/filemap.c --- a/mm/filemap.c~mm-restore-kernel_ds-optimisations +++ a/mm/filemap.c @@ -2103,7 +2103,7 @@ static ssize_t generic_perform_write_2co * cannot take a pagefault with the destination page locked. * So pin the source page to copy it. */ - if (!PageUptodate(page)) { + if (!PageUptodate(page) && !segment_eq(get_fs(), KERNEL_DS)) { unlock_page(page); src_page = alloc_page(GFP_KERNEL); @@ -2228,6 +2228,13 @@ static ssize_t generic_perform_write(str const struct address_space_operations *a_ops = mapping->a_ops; long status = 0; ssize_t written = 0; + unsigned int flags = 0; + + /* + * Copies from kernel address space cannot fail (NFSD is a big user). + */ + if (segment_eq(get_fs(), KERNEL_DS)) + flags |= AOP_FLAG_UNINTERRUPTIBLE; do { struct page *page; @@ -2259,7 +2266,7 @@ again: break; } - status = a_ops->write_begin(file, mapping, pos, bytes, 0, + status = a_ops->write_begin(file, mapping, pos, bytes, flags, &page, &fsdata); if (unlikely(status)) break; _ Patches currently in -mm which might be from npiggin@xxxxxxx are mm-fix-fault-vs-invalidate-race-for-linear-mappings.patch mm-fix-fault-vs-invalidate-race-for-linear-mappings-fix.patch mm-merge-populate-and-nopage-into-fault-fixes-nonlinear.patch mm-merge-nopfn-into-fault.patch mm-remove-legacy-cruft.patch mm-debug-check-for-the-fault-vs-invalidate-race.patch mm-fix-clear_page_dirty_for_io-vs-fault-race.patch git-arm-master.patch slob-rework-freelist-handling.patch slob-remove-bigblock-tracking.patch slob-improved-alignment-handling.patch mm-revert-kernel_ds-buffered-write-optimisation.patch revert-81b0c8713385ce1b1b9058e916edcf9561ad76d6.patch revert-6527c2bdf1f833cc18e8f42bd97973d583e4aa83.patch mm-clean-up-buffered-write-code.patch mm-debug-write-deadlocks.patch mm-trim-more-holes.patch mm-buffered-write-cleanup.patch mm-write-iovec-cleanup.patch mm-fix-pagecache-write-deadlocks.patch mm-buffered-write-iterator.patch fs-fix-data-loss-on-error.patch fs-introduce-write_begin-write_end-and-perform_write-aops.patch mm-restore-kernel_ds-optimisations.patch implement-simple-fs-aops.patch block_dev-convert-to-new-aops.patch ext2-convert-to-new-aops.patch ext3-convert-to-new-aops.patch ext4-convert-to-new-aops.patch xfs-convert-to-new-aops.patch fs-new-cont-helpers.patch fat-convert-to-new-aops.patch hfs-convert-to-new-aops.patch hfsplus-convert-to-new-aops.patch hpfs-convert-to-new-aops.patch bfs-convert-to-new-aops.patch qnx4-convert-to-new-aops.patch reiserfs-use-generic-write.patch reiserfs-convert-to-new-aops.patch reiserfs-use-generic_cont_expand_simple.patch with-reiserfs-no-longer-using-the-weird-generic_cont_expand-remove-it-completely.patch nfs-convert-to-new-aops.patch smb-convert-to-new-aops.patch fuse-convert-to-new-aops.patch hostfs-convert-to-new-aops.patch jffs2-convert-to-new-aops.patch ufs-convert-to-new-aops.patch udf-convert-to-new-aops.patch sysv-convert-to-new-aops.patch minix-convert-to-new-aops.patch jfs-convert-to-new-aops.patch mm-document-fault_data-and-flags.patch fs-introduce-some-page-buffer-invariants.patch fs-introduce-write_begin-write_end-and-perform_write-aops-revoke.patch - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html