[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4 03/15] xenctx: Add -m (--multiple_pages) option to output larger stack
On 03/19/14 11:34, George Dunlap wrote: On 03/18/2014 10:15 PM, Don Slutz wrote:From: Don Slutz <Don@xxxxxxxxxxxxxxx> Important: This is the stack size to display not the configured stack size. Using pictures (for a 3 page configured system): +------------------+ | | | | | | | | | | +------------------+ | | | | | | | | | | +------------------+ | | | | | | SP --> | | | | +------------------+Sorry, what is this a picture of? I can't make any sense out of it. Shouldn't this have only one box, the next have two, and the bottom one have three? This is various pictures of a 3 page stack, and where the SP currently is. Each box is a page. So here the "stack limit" is the end of 1 page. In the sense of how much stack is used, you are right it is 1, 2 and then 3. This tracks with the value passed for "-m" (see next line). Display using "-m 1" since the used stack pages is 1. +------------------+ | | | | | | | | | | +------------------+ | | SP --> | | | | | | | | +------------------+ | | | | | | | | | | +------------------+ Here the stack limit is end of page + 1 full page. Display using "-m 2" since the used stack pages is 2. +------------------+ | | | | | | | | SP --> | | +------------------+ | | | | | | | | | | +------------------+ | | | | | | | | | | +------------------+ Display using "-m 3" since the used stack pages is 3. Here the stack limit is end of page + 2 full pages. Signed-off-by: Don Slutz <Don@xxxxxxxxxxxxxxx> ---v4 Converted from xenctx: Add -2 (--two-pages) option to switch stack size to 8KiBtools/xentrace/xenctx.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/tools/xentrace/xenctx.c b/tools/xentrace/xenctx.c index 42a47f3..6da38cc 100644 --- a/tools/xentrace/xenctx.c +++ b/tools/xentrace/xenctx.c @@ -35,6 +35,7 @@ static struct xenctx { int frame_ptrs; int stack_trace; int disp_all; + int multiple_pages; int all_vcpus; int self_paused; xc_dominfo_t dominfo;@@ -664,6 +665,8 @@ static int print_stack(vcpu_guest_context_any_t *ctx, int vcpu, int width)stack_limit = ((stack_pointer(ctx) + XC_PAGE_SIZE) & ~((guest_word_t) XC_PAGE_SIZE - 1)); + if ( xenctx.multiple_pages > 1 ) + stack_limit += (xenctx.multiple_pages - 1) * XC_PAGE_SIZE; printf("\n"); printf("Stack:\n"); for (i=1; i<5 && stack < stack_limit; i++) { @@ -834,18 +837,21 @@ static void usage(void) kernel_start); printf(" -a, --all display more registers\n"); printf(" -C, --all-vcpus print info for all vcpus\n"); + printf(" -m PAGES, --multiple-pages=PAGES\n");+ printf(" assume the kernel was compiled with PAGES (default 1) of stacks.\n");} Opps, this needs fixing. int main(int argc, char **argv) { int ch; int ret; - static const char *sopts = "fs:hak:SC"; + static const char *sopts = "fs:hak:SCm:"; static const struct option lopts[] = { {"stack-trace", 0, NULL, 'S'}, {"symbol-table", 1, NULL, 's'}, {"frame-pointers", 0, NULL, 'f'}, {"kernel-start", 1, NULL, 'k'}, + {"multiple-pages", 0, NULL, 'm'},I think I would call the long option "kernel-stack-pages" or something like that. "Multiple pages" doesn't really convey much meaning. -m is probably a fine short option, but -n might be more memorable. The issue with "kernel-stack-pages" is that it leads to configured kernel stack pages (which for the pictures above is 3). 3 is most likely not the number to use here. A big part of this is that how a "kernel" knows where it is in the stack can be simple like for a 2 page stack, 1 page is odd, 2nd page is even. (3 pages is most likely more complex, but fence page(s) may help here.) Maybe stack-limit-in-pages is better? -Don Slutz -George _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
|
Lists.xenproject.org is hosted with RackSpace, monitoring our |