The patch titled random: remove some prefetch logic has been added to the -mm tree. Its filename is random-remove-some-prefetch-logic.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** 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 The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: random: remove some prefetch logic From: Matt Mackall <mpm@xxxxxxxxxxx> The urandom output pool (ie the fast path) fits in one cacheline, so this is pretty unnecessary. Further, the output path has already fetched the entire pool to hash it before calling in here. (This was the only user of prefetch_range in the kernel, and it passed in words rather than bytes!) Signed-off-by: Matt Mackall <mpm@xxxxxxxxxxx> Cc: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/char/random.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) diff -puN drivers/char/random.c~random-remove-some-prefetch-logic drivers/char/random.c --- a/drivers/char/random.c~random-remove-some-prefetch-logic +++ a/drivers/char/random.c @@ -457,7 +457,7 @@ static void __add_entropy_words(struct e unsigned long i, add_ptr, tap1, tap2, tap3, tap4, tap5; int input_rotate; int wordmask = r->poolinfo->poolwords - 1; - __u32 w, next_w; + __u32 w; unsigned long flags; /* Taps are constant, so we can load them without holding r->lock. */ @@ -466,17 +466,13 @@ static void __add_entropy_words(struct e tap3 = r->poolinfo->tap3; tap4 = r->poolinfo->tap4; tap5 = r->poolinfo->tap5; - next_w = *in++; spin_lock_irqsave(&r->lock, flags); - prefetch_range(r->pool, wordmask); input_rotate = r->input_rotate; add_ptr = r->add_ptr; while (nwords--) { - w = rol32(next_w, input_rotate & 31); - if (nwords > 0) - next_w = *in++; + w = rol32(*in++, input_rotate & 31); i = add_ptr = (add_ptr - 1) & wordmask; /* XOR in the various taps */ _ Patches currently in -mm which might be from mpm@xxxxxxxxxxx are git-x86.patch maps4-add-proportional-set-size-accounting-in-smaps.patch maps4-rework-task_size-macros.patch maps4-rework-task_size-macros-mips-fix.patch maps4-move-is_swap_pte.patch maps4-introduce-a-generic-page-walker.patch maps4-use-pagewalker-in-clear_refs-and-smaps.patch maps4-simplify-interdependence-of-maps-and-smaps.patch maps4-move-clear_refs-code-to-task_mmuc.patch maps4-regroup-task_mmu-by-interface.patch maps4-add-proc-pid-pagemap-interface.patch maps4-add-proc-pid-pagemap-interface-fix.patch maps4-add-proc-kpagecount-interface.patch maps4-add-proc-kpagecount-interface-fix.patch maps4-add-proc-kpageflags-interface.patch maps4-add-proc-kpageflags-interface-fix.patch maps4-add-proc-kpageflags-interface-fix-2.patch maps4-add-proc-kpageflags-interface-fix-2-fix.patch maps4-make-page-monitoring-proc-file-optional.patch maps4-make-page-monitoring-proc-file-optional-fix.patch remove-unused-code-from-mm-tiny-shmemc.patch drivers-char-randomcwrite_pool-cond_resched-needed.patch random-clean-up-checkpatch-complaints.patch random-consolidate-wakeup-logic.patch random-use-unlocked_ioctl.patch random-reuse-rand_initialize.patch random-improve-variable-naming-clear-extract-buffer.patch random-make-backtracking-attacks-harder.patch random-remove-cacheline-alignment-for-locks.patch random-eliminate-redundant-new_rotate-variable.patch random-remove-some-prefetch-logic.patch random-simplify-add_ptr-logic.patch random-make-mixing-interface-byte-oriented.patch random-simplify-and-rename-credit_entropy_store.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